MVC use concrete types for DiagnosticListener (#11730)

* MVC use concrete types for DiagnosticListener

* Use DiagnosticListener not DiagnosticSource

* Implement interface explicitly

* Code check

* Feedback

* Feedback

* IReadOnlyDictionary

* Remove InstrumentationContext

* DiagnosticSource in RazorPageActivator

* Code check

* Feedback

src/Hosting/Hosting/test/HostingApplicationTests.cs

@@ -88,13 +88,13 @@ namespace Microsoft.AspNetCore.Hosting.Tests
         public void ActivityStopDoesNotFireIfNoListenerAttachedForStart()
         {
             // Arrange
-            var diagnosticSource = new DiagnosticListener("DummySource");
+            var diagnosticListener = new DiagnosticListener("DummySource");
             var logger = new LoggerWithScopes(isEnabled: true);
-            var hostingApplication = CreateApplication(out var features, diagnosticSource: diagnosticSource, logger: logger);
+            var hostingApplication = CreateApplication(out var features, diagnosticListener: diagnosticListener, logger: logger);
             var startFired = false;
             var stopFired = false;
 
-            diagnosticSource.Subscribe(new CallbackDiagnosticListener(pair =>
+            diagnosticListener.Subscribe(new CallbackDiagnosticListener(pair =>
             {
                 // This should not fire
                 if (pair.Key == "Microsoft.AspNetCore.Hosting.HttpRequestIn.Start")
@@ -128,14 +128,14 @@ namespace Microsoft.AspNetCore.Hosting.Tests
         [Fact]
         public void ActivityIsNotCreatedWhenIsEnabledForActivityIsFalse()
         {
-            var diagnosticSource = new DiagnosticListener("DummySource");
+            var diagnosticListener = new DiagnosticListener("DummySource");
-            var hostingApplication = CreateApplication(out var features, diagnosticSource: diagnosticSource);
+            var hostingApplication = CreateApplication(out var features, diagnosticListener: diagnosticListener);
 
             bool eventsFired = false;
             bool isEnabledActivityFired = false;
             bool isEnabledStartFired = false;
 
-            diagnosticSource.Subscribe(new CallbackDiagnosticListener(pair =>
+            diagnosticListener.Subscribe(new CallbackDiagnosticListener(pair =>
             {
                 eventsFired |= pair.Key.StartsWith("Microsoft.AspNetCore.Hosting.HttpRequestIn");
             }), (s, o, arg3) =>
@@ -162,14 +162,14 @@ namespace Microsoft.AspNetCore.Hosting.Tests
         [Fact]
         public void ActivityIsCreatedButNotLoggedWhenIsEnabledForActivityStartIsFalse()
         {
-            var diagnosticSource = new DiagnosticListener("DummySource");
+            var diagnosticListener = new DiagnosticListener("DummySource");
-            var hostingApplication = CreateApplication(out var features, diagnosticSource: diagnosticSource);
+            var hostingApplication = CreateApplication(out var features, diagnosticListener: diagnosticListener);
 
             bool eventsFired = false;
             bool isEnabledStartFired = false;
             bool isEnabledActivityFired = false;
 
-            diagnosticSource.Subscribe(new CallbackDiagnosticListener(pair =>
+            diagnosticListener.Subscribe(new CallbackDiagnosticListener(pair =>
             {
                 eventsFired |= pair.Key.StartsWith("Microsoft.AspNetCore.Hosting.HttpRequestIn");
             }), (s, o, arg3) =>
@@ -199,12 +199,12 @@ namespace Microsoft.AspNetCore.Hosting.Tests
         [Fact]
         public void ActivityIsCreatedAndLogged()
         {
-            var diagnosticSource = new DiagnosticListener("DummySource");
+            var diagnosticListener = new DiagnosticListener("DummySource");
-            var hostingApplication = CreateApplication(out var features, diagnosticSource: diagnosticSource);
+            var hostingApplication = CreateApplication(out var features, diagnosticListener: diagnosticListener);
 
             bool startCalled = false;
 
-            diagnosticSource.Subscribe(new CallbackDiagnosticListener(pair =>
+            diagnosticListener.Subscribe(new CallbackDiagnosticListener(pair =>
             {
                 if (pair.Key == "Microsoft.AspNetCore.Hosting.HttpRequestIn.Start")
                 {
@@ -224,11 +224,11 @@ namespace Microsoft.AspNetCore.Hosting.Tests
         [Fact]
         public void ActivityIsStoppedDuringStopCall()
         {
-            var diagnosticSource = new DiagnosticListener("DummySource");
+            var diagnosticListener = new DiagnosticListener("DummySource");
-            var hostingApplication = CreateApplication(out var features, diagnosticSource: diagnosticSource);
+            var hostingApplication = CreateApplication(out var features, diagnosticListener: diagnosticListener);
 
             bool endCalled = false;
-            diagnosticSource.Subscribe(new CallbackDiagnosticListener(pair =>
+            diagnosticListener.Subscribe(new CallbackDiagnosticListener(pair =>
             {
                 if (pair.Key == "Microsoft.AspNetCore.Hosting.HttpRequestIn.Stop")
                 {
@@ -249,11 +249,11 @@ namespace Microsoft.AspNetCore.Hosting.Tests
         [Fact]
         public void ActivityIsStoppedDuringUnhandledExceptionCall()
         {
-            var diagnosticSource = new DiagnosticListener("DummySource");
+            var diagnosticListener = new DiagnosticListener("DummySource");
-            var hostingApplication = CreateApplication(out var features, diagnosticSource: diagnosticSource);
+            var hostingApplication = CreateApplication(out var features, diagnosticListener: diagnosticListener);
 
             bool endCalled = false;
-            diagnosticSource.Subscribe(new CallbackDiagnosticListener(pair =>
+            diagnosticListener.Subscribe(new CallbackDiagnosticListener(pair =>
             {
                 if (pair.Key == "Microsoft.AspNetCore.Hosting.HttpRequestIn.Stop")
                 {
@@ -273,11 +273,11 @@ namespace Microsoft.AspNetCore.Hosting.Tests
         [Fact]
         public void ActivityIsAvailableDuringUnhandledExceptionCall()
         {
-            var diagnosticSource = new DiagnosticListener("DummySource");
+            var diagnosticListener = new DiagnosticListener("DummySource");
-            var hostingApplication = CreateApplication(out var features, diagnosticSource: diagnosticSource);
+            var hostingApplication = CreateApplication(out var features, diagnosticListener: diagnosticListener);
 
             bool endCalled = false;
-            diagnosticSource.Subscribe(new CallbackDiagnosticListener(pair =>
+            diagnosticListener.Subscribe(new CallbackDiagnosticListener(pair =>
             {
                 if (pair.Key == "Microsoft.AspNetCore.Hosting.UnhandledException")
                 {
@@ -295,10 +295,10 @@ namespace Microsoft.AspNetCore.Hosting.Tests
         [Fact]
         public void ActivityIsAvailibleDuringRequest()
         {
-            var diagnosticSource = new DiagnosticListener("DummySource");
+            var diagnosticListener = new DiagnosticListener("DummySource");
-            var hostingApplication = CreateApplication(out var features, diagnosticSource: diagnosticSource);
+            var hostingApplication = CreateApplication(out var features, diagnosticListener: diagnosticListener);
 
-            diagnosticSource.Subscribe(new CallbackDiagnosticListener(pair => { }),
+            diagnosticListener.Subscribe(new CallbackDiagnosticListener(pair => { }),
                 s =>
                 {
                     if (s.StartsWith("Microsoft.AspNetCore.Hosting.HttpRequestIn"))
@@ -317,10 +317,10 @@ namespace Microsoft.AspNetCore.Hosting.Tests
         [Fact]
         public void ActivityParentIdAndBaggeReadFromHeaders()
         {
-            var diagnosticSource = new DiagnosticListener("DummySource");
+            var diagnosticListener = new DiagnosticListener("DummySource");
-            var hostingApplication = CreateApplication(out var features, diagnosticSource: diagnosticSource);
+            var hostingApplication = CreateApplication(out var features, diagnosticListener: diagnosticListener);
 
-            diagnosticSource.Subscribe(new CallbackDiagnosticListener(pair => { }),
+            diagnosticListener.Subscribe(new CallbackDiagnosticListener(pair => { }),
                 s =>
                 {
                     if (s.StartsWith("Microsoft.AspNetCore.Hosting.HttpRequestIn"))
@@ -349,10 +349,10 @@ namespace Microsoft.AspNetCore.Hosting.Tests
         [Fact]
         public void ActivityTraceParentAndTraceStateFromHeaders()
         {
-            var diagnosticSource = new DiagnosticListener("DummySource");
+            var diagnosticListener = new DiagnosticListener("DummySource");
-            var hostingApplication = CreateApplication(out var features, diagnosticSource: diagnosticSource);
+            var hostingApplication = CreateApplication(out var features, diagnosticListener: diagnosticListener);
 
-            diagnosticSource.Subscribe(new CallbackDiagnosticListener(pair => { }),
+            diagnosticListener.Subscribe(new CallbackDiagnosticListener(pair => { }),
                 s =>
                 {
                     if (s.StartsWith("Microsoft.AspNetCore.Hosting.HttpRequestIn"))
@@ -385,11 +385,11 @@ namespace Microsoft.AspNetCore.Hosting.Tests
         [Fact]
         public void ActivityOnExportHookIsCalled()
         {
-            var diagnosticSource = new DiagnosticListener("DummySource");
+            var diagnosticListener = new DiagnosticListener("DummySource");
-            var hostingApplication = CreateApplication(out var features, diagnosticSource: diagnosticSource);
+            var hostingApplication = CreateApplication(out var features, diagnosticListener: diagnosticListener);
 
             bool onActivityImportCalled = false;
-            diagnosticSource.Subscribe(
+            diagnosticListener.Subscribe(
                 observer: new CallbackDiagnosticListener(pair => { }),
                 isEnabled: (s, o, _) => true,
                 onActivityImport: (activity, context) =>
@@ -422,7 +422,7 @@ namespace Microsoft.AspNetCore.Hosting.Tests
         }
 
         private static HostingApplication CreateApplication(out FeatureCollection features,
-            DiagnosticListener diagnosticSource = null, ILogger logger = null, Action<DefaultHttpContext> configure = null)
+            DiagnosticListener diagnosticListener = null, ILogger logger = null, Action<DefaultHttpContext> configure = null)
         {
             var httpContextFactory = new Mock<IHttpContextFactory>();
 
@@ -436,7 +436,7 @@ namespace Microsoft.AspNetCore.Hosting.Tests
             var hostingApplication = new HostingApplication(
                 ctx => Task.CompletedTask,
                 logger ?? new NullScopeLogger(),
-                diagnosticSource ?? new NoopDiagnosticSource(),
+                diagnosticListener ?? new NoopDiagnosticListener(),
                 httpContextFactory.Object);
 
             return hostingApplication;
@@ -490,11 +490,11 @@ namespace Microsoft.AspNetCore.Hosting.Tests
             }
         }
 
-        private class NoopDiagnosticSource : DiagnosticListener
+        private class NoopDiagnosticListener : DiagnosticListener
         {
             private readonly bool _isEnabled;
 
-            public NoopDiagnosticSource(bool isEnabled = false) : base("DummyListener")
+            public NoopDiagnosticListener(bool isEnabled = false) : base("DummyListener")
             {
                 _isEnabled = isEnabled;
             }

src/Http/Http/src/DefaultHttpContext.cs

@@ -159,7 +159,7 @@ namespace Microsoft.AspNetCore.Http
 
         // This property exists because of backwards compatibility.
         // We send an anonymous object with an HttpContext property
-        // via DiagnosticSource in various events throughout the pipeline. Instead
+        // via DiagnosticListener in various events throughout the pipeline. Instead
         // we just send the HttpContext to avoid extra allocations
         [EditorBrowsable(EditorBrowsableState.Never)]
         public HttpContext HttpContext => this;

src/Mvc/Mvc.Core/ref/Microsoft.AspNetCore.Mvc.Core.netcoreapp3.0.cs

@@ -1726,6 +1726,310 @@ namespace Microsoft.AspNetCore.Mvc.Core.Infrastructure
     {
     }
 }
+namespace Microsoft.AspNetCore.Mvc.Diagnostics
+{
+    public sealed partial class AfterAction : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.AfterAction";
+        public AfterAction(Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor actionDescriptor, Microsoft.AspNetCore.Http.HttpContext httpContext, Microsoft.AspNetCore.Routing.RouteData routeData) { }
+        public Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Http.HttpContext HttpContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+        public Microsoft.AspNetCore.Routing.RouteData RouteData { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+    }
+    public sealed partial class AfterActionMethod : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.AfterActionMethod";
+        public AfterActionMethod(Microsoft.AspNetCore.Mvc.ActionContext actionContext, System.Collections.Generic.IReadOnlyDictionary<string, object> arguments, object controller, Microsoft.AspNetCore.Mvc.IActionResult result) { }
+        public Microsoft.AspNetCore.Mvc.ActionContext ActionContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public System.Collections.Generic.IReadOnlyDictionary<string, object> Arguments { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public object Controller { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.IActionResult Result { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+    }
+    public sealed partial class AfterActionResult : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.AfterActionResult";
+        public AfterActionResult(Microsoft.AspNetCore.Mvc.ActionContext actionContext, Microsoft.AspNetCore.Mvc.IActionResult result) { }
+        public Microsoft.AspNetCore.Mvc.ActionContext ActionContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.IActionResult Result { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+    }
+    public sealed partial class AfterOnActionExecuted : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.AfterOnActionExecuted";
+        public AfterOnActionExecuted(Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor actionDescriptor, Microsoft.AspNetCore.Mvc.Filters.ActionExecutedContext actionExecutedContext, Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata filter) { }
+        public Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.ActionExecutedContext ActionExecutedContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata Filter { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+    }
+    public sealed partial class AfterOnActionExecuting : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.AfterOnActionExecuting";
+        public AfterOnActionExecuting(Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor actionDescriptor, Microsoft.AspNetCore.Mvc.Filters.ActionExecutingContext actionExecutingContext, Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata filter) { }
+        public Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.ActionExecutingContext ActionExecutingContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata Filter { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+    }
+    public sealed partial class AfterOnActionExecution : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.AfterOnActionExecution";
+        public AfterOnActionExecution(Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor actionDescriptor, Microsoft.AspNetCore.Mvc.Filters.ActionExecutedContext actionExecutedContext, Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata filter) { }
+        public Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.ActionExecutedContext ActionExecutedContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata Filter { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+    }
+    public sealed partial class AfterOnAuthorization : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.AfterOnAuthorization";
+        public AfterOnAuthorization(Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor actionDescriptor, Microsoft.AspNetCore.Mvc.Filters.AuthorizationFilterContext authorizationContext, Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata filter) { }
+        public Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.AuthorizationFilterContext AuthorizationContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata Filter { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+    }
+    public sealed partial class AfterOnException : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.AfterOnException";
+        public AfterOnException(Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor actionDescriptor, Microsoft.AspNetCore.Mvc.Filters.ExceptionContext exceptionContext, Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata filter) { }
+        public Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.ExceptionContext ExceptionContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata Filter { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+    }
+    public sealed partial class AfterOnResourceExecuted : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.AfterOnResourceExecuted";
+        public AfterOnResourceExecuted(Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor actionDescriptor, Microsoft.AspNetCore.Mvc.Filters.ResourceExecutedContext resourceExecutedContext, Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata filter) { }
+        public Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata Filter { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.ResourceExecutedContext ResourceExecutedContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+    }
+    public sealed partial class AfterOnResourceExecuting : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.AfterOnResourceExecuting";
+        public AfterOnResourceExecuting(Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor actionDescriptor, Microsoft.AspNetCore.Mvc.Filters.ResourceExecutingContext resourceExecutingContext, Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata filter) { }
+        public Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata Filter { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.ResourceExecutingContext ResourceExecutingContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+    }
+    public sealed partial class AfterOnResourceExecution : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.AfterOnResourceExecution";
+        public AfterOnResourceExecution(Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor actionDescriptor, Microsoft.AspNetCore.Mvc.Filters.ResourceExecutedContext resourceExecutedContext, Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata filter) { }
+        public Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata Filter { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.ResourceExecutedContext ResourceExecutedContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+    }
+    public sealed partial class AfterOnResultExecuted : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.AfterOnResultExecuted";
+        public AfterOnResultExecuted(Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor actionDescriptor, Microsoft.AspNetCore.Mvc.Filters.ResultExecutedContext resultExecutedContext, Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata filter) { }
+        public Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata Filter { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.ResultExecutedContext ResultExecutedContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+    }
+    public sealed partial class AfterOnResultExecuting : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.AfterOnResultExecuting";
+        public AfterOnResultExecuting(Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor actionDescriptor, Microsoft.AspNetCore.Mvc.Filters.ResultExecutingContext resultExecutingContext, Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata filter) { }
+        public Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata Filter { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.ResultExecutingContext ResultExecutingContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+    }
+    public sealed partial class AfterOnResultExecution : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.AfterOnResultExecution";
+        public AfterOnResultExecution(Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor actionDescriptor, Microsoft.AspNetCore.Mvc.Filters.ResultExecutedContext resultExecutedContext, Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata filter) { }
+        public Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata Filter { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.ResultExecutedContext ResultExecutedContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+    }
+    public sealed partial class BeforeAction : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.BeforeAction";
+        public BeforeAction(Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor actionDescriptor, Microsoft.AspNetCore.Http.HttpContext httpContext, Microsoft.AspNetCore.Routing.RouteData routeData) { }
+        public Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Http.HttpContext HttpContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+        public Microsoft.AspNetCore.Routing.RouteData RouteData { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+    }
+    public sealed partial class BeforeActionMethod : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.BeforeActionMethod";
+        public BeforeActionMethod(Microsoft.AspNetCore.Mvc.ActionContext actionContext, System.Collections.Generic.IReadOnlyDictionary<string, object> arguments, object controller) { }
+        public Microsoft.AspNetCore.Mvc.ActionContext ActionContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public System.Collections.Generic.IReadOnlyDictionary<string, object> Arguments { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public object Controller { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+    }
+    public sealed partial class BeforeActionResult : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.BeforeActionResult";
+        public BeforeActionResult(Microsoft.AspNetCore.Mvc.ActionContext actionContext, Microsoft.AspNetCore.Mvc.IActionResult result) { }
+        public Microsoft.AspNetCore.Mvc.ActionContext ActionContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.IActionResult Result { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+    }
+    public sealed partial class BeforeOnActionExecuted : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.BeforeOnActionExecuted";
+        public BeforeOnActionExecuted(Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor actionDescriptor, Microsoft.AspNetCore.Mvc.Filters.ActionExecutedContext actionExecutedContext, Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata filter) { }
+        public Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.ActionExecutedContext ActionExecutedContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata Filter { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+    }
+    public sealed partial class BeforeOnActionExecuting : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.BeforeOnActionExecuting";
+        public BeforeOnActionExecuting(Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor actionDescriptor, Microsoft.AspNetCore.Mvc.Filters.ActionExecutingContext actionExecutingContext, Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata filter) { }
+        public Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.ActionExecutingContext ActionExecutingContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata Filter { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+    }
+    public sealed partial class BeforeOnActionExecution : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.BeforeOnActionExecution";
+        public BeforeOnActionExecution(Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor actionDescriptor, Microsoft.AspNetCore.Mvc.Filters.ActionExecutingContext actionExecutingContext, Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata filter) { }
+        public Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.ActionExecutingContext ActionExecutingContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata Filter { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+    }
+    public sealed partial class BeforeOnAuthorization : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.BeforeOnAuthorization";
+        public BeforeOnAuthorization(Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor actionDescriptor, Microsoft.AspNetCore.Mvc.Filters.AuthorizationFilterContext authorizationContext, Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata filter) { }
+        public Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.AuthorizationFilterContext AuthorizationContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata Filter { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+    }
+    public sealed partial class BeforeOnException : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.BeforeOnException";
+        public BeforeOnException(Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor actionDescriptor, Microsoft.AspNetCore.Mvc.Filters.ExceptionContext exceptionContext, Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata filter) { }
+        public Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.ExceptionContext ExceptionContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata Filter { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+    }
+    public sealed partial class BeforeOnResourceExecuted : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.BeforeOnResourceExecuted";
+        public BeforeOnResourceExecuted(Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor actionDescriptor, Microsoft.AspNetCore.Mvc.Filters.ResourceExecutedContext resourceExecutedContext, Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata filter) { }
+        public Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata Filter { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.ResourceExecutedContext ResourceExecutedContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+    }
+    public sealed partial class BeforeOnResourceExecuting : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.BeforeOnResourceExecuting";
+        public BeforeOnResourceExecuting(Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor actionDescriptor, Microsoft.AspNetCore.Mvc.Filters.ResourceExecutingContext resourceExecutingContext, Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata filter) { }
+        public Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata Filter { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.ResourceExecutingContext ResourceExecutingContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+    }
+    public sealed partial class BeforeOnResourceExecution : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.BeforeOnResourceExecution";
+        public BeforeOnResourceExecution(Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor actionDescriptor, Microsoft.AspNetCore.Mvc.Filters.ResourceExecutingContext resourceExecutingContext, Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata filter) { }
+        public Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata Filter { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.ResourceExecutingContext ResourceExecutingContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+    }
+    public sealed partial class BeforeOnResultExecuted : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.BeforeOnResultExecuted";
+        public BeforeOnResultExecuted(Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor actionDescriptor, Microsoft.AspNetCore.Mvc.Filters.ResultExecutedContext resultExecutedContext, Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata filter) { }
+        public Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata Filter { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.ResultExecutedContext ResultExecutedContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+    }
+    public sealed partial class BeforeOnResultExecuting : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.BeforeOnResultExecuting";
+        public BeforeOnResultExecuting(Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor actionDescriptor, Microsoft.AspNetCore.Mvc.Filters.ResultExecutingContext resultExecutingContext, Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata filter) { }
+        public Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata Filter { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.ResultExecutingContext ResultExecutingContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+    }
+    public sealed partial class BeforeOnResultExecution : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.BeforeOnResultExecution";
+        public BeforeOnResultExecution(Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor actionDescriptor, Microsoft.AspNetCore.Mvc.Filters.ResultExecutingContext resultExecutingContext, Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata filter) { }
+        public Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata Filter { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.ResultExecutingContext ResultExecutingContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+    }
+    public abstract partial class EventData : System.Collections.Generic.IEnumerable<System.Collections.Generic.KeyValuePair<string, object>>, System.Collections.Generic.IReadOnlyCollection<System.Collections.Generic.KeyValuePair<string, object>>, System.Collections.Generic.IReadOnlyList<System.Collections.Generic.KeyValuePair<string, object>>, System.Collections.IEnumerable
+    {
+        protected const string EventNamespace = "Microsoft.AspNetCore.Mvc.";
+        protected EventData() { }
+        protected abstract int Count { get; }
+        protected abstract System.Collections.Generic.KeyValuePair<string, object> this[int index] { get; }
+        int System.Collections.Generic.IReadOnlyCollection<System.Collections.Generic.KeyValuePair<System.String,System.Object>>.Count { get { throw null; } }
+        System.Collections.Generic.KeyValuePair<string, object> System.Collections.Generic.IReadOnlyList<System.Collections.Generic.KeyValuePair<System.String,System.Object>>.this[int index] { get { throw null; } }
+        System.Collections.Generic.IEnumerator<System.Collections.Generic.KeyValuePair<string, object>> System.Collections.Generic.IEnumerable<System.Collections.Generic.KeyValuePair<System.String,System.Object>>.GetEnumerator() { throw null; }
+        System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator() { throw null; }
+        [System.Runtime.InteropServices.StructLayoutAttribute(System.Runtime.InteropServices.LayoutKind.Sequential)]
+        public partial struct Enumerator : System.Collections.Generic.IEnumerator<System.Collections.Generic.KeyValuePair<string, object>>, System.Collections.IEnumerator, System.IDisposable
+        {
+            private object _dummy;
+            private int _dummyPrimitive;
+            public System.Collections.Generic.KeyValuePair<string, object> Current { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+            object System.Collections.IEnumerator.Current { get { throw null; } }
+            public void Dispose() { }
+            public bool MoveNext() { throw null; }
+            void System.Collections.IEnumerator.Reset() { }
+        }
+    }
+}
 namespace Microsoft.AspNetCore.Mvc.Filters
 {
     [System.AttributeUsageAttribute(System.AttributeTargets.Class | System.AttributeTargets.Method, AllowMultiple=true, Inherited=true)]

src/Mvc/Mvc.Core/src/Diagnostics/EventData.cs

@@ -0,0 +1,64 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Collections;
+using System.Collections.Generic;
+
+namespace Microsoft.AspNetCore.Mvc.Diagnostics
+{
+    public abstract class EventData : IReadOnlyList<KeyValuePair<string, object>>
+    {
+        protected const string EventNamespace = "Microsoft.AspNetCore.Mvc.";
+
+        protected abstract int Count { get; }
+        protected abstract KeyValuePair<string, object> this[int index] { get; }
+
+        int IReadOnlyCollection<KeyValuePair<string, object>>.Count => Count;
+        KeyValuePair<string, object> IReadOnlyList<KeyValuePair<string, object>>.this[int index] => this[index];
+
+        Enumerator GetEnumerator() => new Enumerator(this);
+
+        IEnumerator<KeyValuePair<string, object>> IEnumerable<KeyValuePair<string, object>>.GetEnumerator()
+            => GetEnumerator();
+
+        IEnumerator IEnumerable.GetEnumerator()
+            => GetEnumerator();
+
+        public struct Enumerator : IEnumerator<KeyValuePair<string, object>>
+        {
+            private readonly EventData _eventData;
+            private readonly int _count;
+
+            private int _index;
+
+            public KeyValuePair<string, object> Current { get; private set; }
+
+            internal Enumerator(EventData eventData)
+            {
+                _eventData = eventData;
+                _count = eventData.Count;
+                _index = -1;
+                Current = default;
+            }
+
+            public bool MoveNext()
+            {
+                var index = _index + 1;
+                if (index >= _count)
+                {
+                    return false;
+                }
+
+                _index = index;
+
+                Current = _eventData[index];
+                return true;
+            }
+
+            public void Dispose() { }
+            object IEnumerator.Current => Current;
+            void IEnumerator.Reset() => throw new NotSupportedException();
+        }
+    }
+}

src/Mvc/Mvc.Core/src/Diagnostics/MvcDiagnostics.cs

@@ -0,0 +1,736 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Mvc.Abstractions;
+using Microsoft.AspNetCore.Mvc.Filters;
+using Microsoft.AspNetCore.Routing;
+
+namespace Microsoft.AspNetCore.Mvc.Diagnostics
+{
+    public sealed class BeforeAction : EventData
+    {
+        public const string EventName = EventNamespace + nameof(BeforeAction);
+        public BeforeAction(ActionDescriptor actionDescriptor, HttpContext httpContext, RouteData routeData)
+        {
+            ActionDescriptor = actionDescriptor;
+            HttpContext = httpContext;
+            RouteData = routeData;
+        }
+
+        public ActionDescriptor ActionDescriptor { get; }
+        public HttpContext HttpContext { get; }
+        public RouteData RouteData { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(HttpContext), HttpContext),
+            2 => new KeyValuePair<string, object>(nameof(RouteData), RouteData),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class AfterAction : EventData
+    {
+        public const string EventName = EventNamespace + nameof(AfterAction);
+
+        public AfterAction(ActionDescriptor actionDescriptor, HttpContext httpContext, RouteData routeData)
+        {
+            ActionDescriptor = actionDescriptor;
+            HttpContext = httpContext;
+            RouteData = routeData;
+        }
+
+        public ActionDescriptor ActionDescriptor { get; }
+        public HttpContext HttpContext { get; }
+        public RouteData RouteData { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(HttpContext), HttpContext),
+            2 => new KeyValuePair<string, object>(nameof(RouteData), RouteData),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class BeforeOnAuthorization : EventData
+    {
+        public const string EventName = EventNamespace + nameof(BeforeOnAuthorization);
+
+        public BeforeOnAuthorization(ActionDescriptor actionDescriptor, AuthorizationFilterContext authorizationContext, IFilterMetadata filter)
+        {
+            ActionDescriptor = actionDescriptor;
+            AuthorizationContext = authorizationContext;
+            Filter = filter;
+        }
+
+        public ActionDescriptor ActionDescriptor { get; }
+        public AuthorizationFilterContext AuthorizationContext { get; }
+        public IFilterMetadata Filter { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(AuthorizationContext), AuthorizationContext),
+            2 => new KeyValuePair<string, object>(nameof(Filter), Filter),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class AfterOnAuthorization : EventData
+    {
+        public const string EventName = EventNamespace + nameof(AfterOnAuthorization);
+
+        public AfterOnAuthorization(ActionDescriptor actionDescriptor, AuthorizationFilterContext authorizationContext, IFilterMetadata filter)
+        {
+            ActionDescriptor = actionDescriptor;
+            AuthorizationContext = authorizationContext;
+            Filter = filter;
+        }
+
+        public ActionDescriptor ActionDescriptor { get; }
+        public AuthorizationFilterContext AuthorizationContext { get; }
+        public IFilterMetadata Filter { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(AuthorizationContext), AuthorizationContext),
+            2 => new KeyValuePair<string, object>(nameof(Filter), Filter),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class BeforeOnResourceExecution : EventData
+    {
+        public const string EventName = EventNamespace + nameof(BeforeOnResourceExecution);
+
+        public BeforeOnResourceExecution(ActionDescriptor actionDescriptor, ResourceExecutingContext resourceExecutingContext, IFilterMetadata filter)
+        {
+            ActionDescriptor = actionDescriptor;
+            ResourceExecutingContext = resourceExecutingContext;
+            Filter = filter;
+        }
+
+        public ActionDescriptor ActionDescriptor { get; }
+        public ResourceExecutingContext ResourceExecutingContext { get; }
+        public IFilterMetadata Filter { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(ResourceExecutingContext), ResourceExecutingContext),
+            2 => new KeyValuePair<string, object>(nameof(Filter), Filter),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class AfterOnResourceExecution : EventData
+    {
+        public const string EventName = EventNamespace + nameof(AfterOnResourceExecution);
+
+        public AfterOnResourceExecution(ActionDescriptor actionDescriptor, ResourceExecutedContext resourceExecutedContext, IFilterMetadata filter)
+        {
+            ActionDescriptor = actionDescriptor;
+            ResourceExecutedContext = resourceExecutedContext;
+            Filter = filter;
+        }
+
+        public ActionDescriptor ActionDescriptor { get; }
+        public ResourceExecutedContext ResourceExecutedContext { get; }
+        public IFilterMetadata Filter { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(ResourceExecutedContext), ResourceExecutedContext),
+            2 => new KeyValuePair<string, object>(nameof(Filter), Filter),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class BeforeOnResourceExecuting : EventData
+    {
+        public const string EventName = EventNamespace + nameof(BeforeOnResourceExecuting);
+
+        public BeforeOnResourceExecuting(ActionDescriptor actionDescriptor, ResourceExecutingContext resourceExecutingContext, IFilterMetadata filter)
+        {
+            ActionDescriptor = actionDescriptor;
+            ResourceExecutingContext = resourceExecutingContext;
+            Filter = filter;
+        }
+
+        public ActionDescriptor ActionDescriptor { get; }
+        public ResourceExecutingContext ResourceExecutingContext { get; }
+        public IFilterMetadata Filter { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(ResourceExecutingContext), ResourceExecutingContext),
+            2 => new KeyValuePair<string, object>(nameof(Filter), Filter),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class AfterOnResourceExecuting : EventData
+    {
+        public const string EventName = EventNamespace + nameof(AfterOnResourceExecuting);
+
+        public AfterOnResourceExecuting(ActionDescriptor actionDescriptor, ResourceExecutingContext resourceExecutingContext, IFilterMetadata filter)
+        {
+            ActionDescriptor = actionDescriptor;
+            ResourceExecutingContext = resourceExecutingContext;
+            Filter = filter;
+        }
+
+        public ActionDescriptor ActionDescriptor { get; }
+        public ResourceExecutingContext ResourceExecutingContext { get; }
+        public IFilterMetadata Filter { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(ResourceExecutingContext), ResourceExecutingContext),
+            2 => new KeyValuePair<string, object>(nameof(Filter), Filter),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class BeforeOnResourceExecuted : EventData
+    {
+        public const string EventName = EventNamespace + nameof(BeforeOnResourceExecuted);
+
+        public BeforeOnResourceExecuted(ActionDescriptor actionDescriptor, ResourceExecutedContext resourceExecutedContext, IFilterMetadata filter)
+        {
+            ActionDescriptor = actionDescriptor;
+            ResourceExecutedContext = resourceExecutedContext;
+            Filter = filter;
+        }
+
+        public ActionDescriptor ActionDescriptor { get; }
+        public ResourceExecutedContext ResourceExecutedContext { get; }
+        public IFilterMetadata Filter { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(ResourceExecutedContext), ResourceExecutedContext),
+            2 => new KeyValuePair<string, object>(nameof(Filter), Filter),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class AfterOnResourceExecuted : EventData
+    {
+        public const string EventName = EventNamespace + nameof(AfterOnResourceExecuted);
+
+        public AfterOnResourceExecuted(ActionDescriptor actionDescriptor, ResourceExecutedContext resourceExecutedContext, IFilterMetadata filter)
+        {
+            ActionDescriptor = actionDescriptor;
+            ResourceExecutedContext = resourceExecutedContext;
+            Filter = filter;
+        }
+
+        public ActionDescriptor ActionDescriptor { get; }
+        public ResourceExecutedContext ResourceExecutedContext { get; }
+        public IFilterMetadata Filter { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(ResourceExecutedContext), ResourceExecutedContext),
+            2 => new KeyValuePair<string, object>(nameof(Filter), Filter),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class BeforeOnException : EventData
+    {
+        public const string EventName = EventNamespace + nameof(BeforeOnException);
+
+        public BeforeOnException(ActionDescriptor actionDescriptor, ExceptionContext exceptionContext, IFilterMetadata filter)
+        {
+            ActionDescriptor = actionDescriptor;
+            ExceptionContext = exceptionContext;
+            Filter = filter;
+        }
+
+        public ActionDescriptor ActionDescriptor { get; }
+        public ExceptionContext ExceptionContext { get; }
+        public IFilterMetadata Filter { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(ExceptionContext), ExceptionContext),
+            2 => new KeyValuePair<string, object>(nameof(Filter), Filter),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class AfterOnException : EventData
+    {
+        public const string EventName = EventNamespace + nameof(AfterOnException);
+
+        public AfterOnException(ActionDescriptor actionDescriptor, ExceptionContext exceptionContext, IFilterMetadata filter)
+        {
+            ActionDescriptor = actionDescriptor;
+            ExceptionContext = exceptionContext;
+            Filter = filter;
+        }
+
+        public ActionDescriptor ActionDescriptor { get; }
+        public ExceptionContext ExceptionContext { get; }
+        public IFilterMetadata Filter { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(ExceptionContext), ExceptionContext),
+            2 => new KeyValuePair<string, object>(nameof(Filter), Filter),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class BeforeOnActionExecution : EventData
+    {
+        public const string EventName = EventNamespace + nameof(BeforeOnActionExecution);
+
+        public BeforeOnActionExecution(ActionDescriptor actionDescriptor, ActionExecutingContext actionExecutingContext, IFilterMetadata filter)
+        {
+            ActionDescriptor = actionDescriptor;
+            ActionExecutingContext = actionExecutingContext;
+            Filter = filter;
+        }
+
+        public ActionDescriptor ActionDescriptor { get; }
+        public ActionExecutingContext ActionExecutingContext { get; }
+        public IFilterMetadata Filter { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(ActionExecutingContext), ActionExecutingContext),
+            2 => new KeyValuePair<string, object>(nameof(Filter), Filter),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class AfterOnActionExecution : EventData
+    {
+        public const string EventName = EventNamespace + nameof(AfterOnActionExecution);
+
+        public AfterOnActionExecution(ActionDescriptor actionDescriptor, ActionExecutedContext actionExecutedContext, IFilterMetadata filter)
+        {
+            ActionDescriptor = actionDescriptor;
+            ActionExecutedContext = actionExecutedContext;
+            Filter = filter;
+        }
+
+        public ActionDescriptor ActionDescriptor { get; }
+        public ActionExecutedContext ActionExecutedContext { get; }
+        public IFilterMetadata Filter { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(ActionExecutedContext), ActionExecutedContext),
+            2 => new KeyValuePair<string, object>(nameof(Filter), Filter),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class BeforeOnActionExecuting : EventData
+    {
+        public const string EventName = EventNamespace + nameof(BeforeOnActionExecuting);
+
+        public BeforeOnActionExecuting(ActionDescriptor actionDescriptor, ActionExecutingContext actionExecutingContext, IFilterMetadata filter)
+        {
+            ActionDescriptor = actionDescriptor;
+            ActionExecutingContext = actionExecutingContext;
+            Filter = filter;
+        }
+
+        public ActionDescriptor ActionDescriptor { get; }
+        public ActionExecutingContext ActionExecutingContext { get; }
+        public IFilterMetadata Filter { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(ActionExecutingContext), ActionExecutingContext),
+            2 => new KeyValuePair<string, object>(nameof(Filter), Filter),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class AfterOnActionExecuting : EventData
+    {
+        public const string EventName = EventNamespace + nameof(AfterOnActionExecuting);
+
+        public AfterOnActionExecuting(ActionDescriptor actionDescriptor, ActionExecutingContext actionExecutingContext, IFilterMetadata filter)
+        {
+            ActionDescriptor = actionDescriptor;
+            ActionExecutingContext = actionExecutingContext;
+            Filter = filter;
+        }
+
+        public ActionDescriptor ActionDescriptor { get; }
+        public ActionExecutingContext ActionExecutingContext { get; }
+        public IFilterMetadata Filter { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(ActionExecutingContext), ActionExecutingContext),
+            2 => new KeyValuePair<string, object>(nameof(Filter), Filter),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class BeforeOnActionExecuted : EventData
+    {
+        public const string EventName = EventNamespace + nameof(BeforeOnActionExecuted);
+
+        public BeforeOnActionExecuted(ActionDescriptor actionDescriptor, ActionExecutedContext actionExecutedContext, IFilterMetadata filter)
+        {
+            ActionDescriptor = actionDescriptor;
+            ActionExecutedContext = actionExecutedContext;
+            Filter = filter;
+        }
+
+        public ActionDescriptor ActionDescriptor { get; }
+        public ActionExecutedContext ActionExecutedContext { get; }
+        public IFilterMetadata Filter { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(ActionExecutedContext), ActionExecutedContext),
+            2 => new KeyValuePair<string, object>(nameof(Filter), Filter),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class AfterOnActionExecuted : EventData
+    {
+        public const string EventName = EventNamespace + nameof(AfterOnActionExecuted);
+
+        public AfterOnActionExecuted(ActionDescriptor actionDescriptor, ActionExecutedContext actionExecutedContext, IFilterMetadata filter)
+        {
+            ActionDescriptor = actionDescriptor;
+            ActionExecutedContext = actionExecutedContext;
+            Filter = filter;
+        }
+
+        public ActionDescriptor ActionDescriptor { get; }
+        public ActionExecutedContext ActionExecutedContext { get; }
+        public IFilterMetadata Filter { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(ActionExecutedContext), ActionExecutedContext),
+            2 => new KeyValuePair<string, object>(nameof(Filter), Filter),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class BeforeActionMethod : EventData
+    {
+        public const string EventName = EventNamespace + nameof(BeforeActionMethod);
+
+        public BeforeActionMethod(ActionContext actionContext, IReadOnlyDictionary<string, object> arguments, object controller)
+        {
+            ActionContext = actionContext;
+            Arguments = arguments;
+            Controller = controller;
+        }
+
+        public ActionContext ActionContext { get; }
+        public IReadOnlyDictionary<string, object> Arguments { get; }
+        public object Controller { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionContext), ActionContext),
+            1 => new KeyValuePair<string, object>(nameof(Arguments), Arguments),
+            2 => new KeyValuePair<string, object>(nameof(Controller), Controller),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class AfterActionMethod : EventData
+    {
+        public const string EventName = EventNamespace + nameof(AfterActionMethod);
+
+        public AfterActionMethod(ActionContext actionContext, IReadOnlyDictionary<string, object> arguments, object controller, IActionResult result)
+        {
+            ActionContext = actionContext;
+            Arguments = arguments;
+            Controller = controller;
+            Result = result;
+        }
+
+        public ActionContext ActionContext { get; }
+        public IReadOnlyDictionary<string, object> Arguments { get; }
+        public object Controller { get; }
+        public IActionResult Result { get; }
+
+        protected override int Count => 4;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionContext), ActionContext),
+            1 => new KeyValuePair<string, object>(nameof(Controller), Controller),
+            2 => new KeyValuePair<string, object>(nameof(Controller), Controller),
+            3 => new KeyValuePair<string, object>(nameof(Result), Result),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class BeforeOnResultExecution : EventData
+    {
+        public const string EventName = EventNamespace + nameof(BeforeOnResultExecution);
+
+        public BeforeOnResultExecution(ActionDescriptor actionDescriptor, ResultExecutingContext resultExecutingContext, IFilterMetadata filter)
+        {
+            ActionDescriptor = actionDescriptor;
+            ResultExecutingContext = resultExecutingContext;
+            Filter = filter;
+        }
+
+        public ActionDescriptor ActionDescriptor { get; }
+        public ResultExecutingContext ResultExecutingContext { get; }
+        public IFilterMetadata Filter { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(ResultExecutingContext), ResultExecutingContext),
+            2 => new KeyValuePair<string, object>(nameof(Filter), Filter),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class AfterOnResultExecution : EventData
+    {
+        public const string EventName = EventNamespace + nameof(AfterOnResultExecution);
+
+        public AfterOnResultExecution(ActionDescriptor actionDescriptor, ResultExecutedContext resultExecutedContext, IFilterMetadata filter)
+        {
+            ActionDescriptor = actionDescriptor;
+            ResultExecutedContext = resultExecutedContext;
+            Filter = filter;
+        }
+
+        public ActionDescriptor ActionDescriptor { get; }
+        public ResultExecutedContext ResultExecutedContext { get; }
+        public IFilterMetadata Filter { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(ResultExecutedContext), ResultExecutedContext),
+            2 => new KeyValuePair<string, object>(nameof(Filter), Filter),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class BeforeOnResultExecuting : EventData
+    {
+        public const string EventName = EventNamespace + nameof(BeforeOnResultExecuting);
+
+        public BeforeOnResultExecuting(ActionDescriptor actionDescriptor, ResultExecutingContext resultExecutingContext, IFilterMetadata filter)
+        {
+            ActionDescriptor = actionDescriptor;
+            ResultExecutingContext = resultExecutingContext;
+            Filter = filter;
+        }
+
+        public ActionDescriptor ActionDescriptor { get; }
+        public ResultExecutingContext ResultExecutingContext { get; }
+        public IFilterMetadata Filter { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(ResultExecutingContext), ResultExecutingContext),
+            2 => new KeyValuePair<string, object>(nameof(Filter), Filter),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class AfterOnResultExecuting : EventData
+    {
+        public const string EventName = EventNamespace + nameof(AfterOnResultExecuting);
+
+        public AfterOnResultExecuting(ActionDescriptor actionDescriptor, ResultExecutingContext resultExecutingContext, IFilterMetadata filter)
+        {
+            ActionDescriptor = actionDescriptor;
+            ResultExecutingContext = resultExecutingContext;
+            Filter = filter;
+        }
+
+        public ActionDescriptor ActionDescriptor { get; }
+        public ResultExecutingContext ResultExecutingContext { get; }
+        public IFilterMetadata Filter { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(ResultExecutingContext), ResultExecutingContext),
+            2 => new KeyValuePair<string, object>(nameof(Filter), Filter),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class BeforeOnResultExecuted : EventData
+    {
+        public const string EventName = EventNamespace + nameof(BeforeOnResultExecuted);
+
+        public BeforeOnResultExecuted(ActionDescriptor actionDescriptor, ResultExecutedContext resultExecutedContext, IFilterMetadata filter)
+        {
+            ActionDescriptor = actionDescriptor;
+            ResultExecutedContext = resultExecutedContext;
+            Filter = filter;
+        }
+
+        public ActionDescriptor ActionDescriptor { get; }
+        public ResultExecutedContext ResultExecutedContext { get; }
+        public IFilterMetadata Filter { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(ResultExecutedContext), ResultExecutedContext),
+            2 => new KeyValuePair<string, object>(nameof(Filter), Filter),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class AfterOnResultExecuted : EventData
+    {
+        public const string EventName = EventNamespace + nameof(AfterOnResultExecuted);
+
+        public AfterOnResultExecuted(ActionDescriptor actionDescriptor, ResultExecutedContext resultExecutedContext, IFilterMetadata filter)
+        {
+            ActionDescriptor = actionDescriptor;
+            ResultExecutedContext = resultExecutedContext;
+            Filter = filter;
+        }
+
+        public ActionDescriptor ActionDescriptor { get; }
+        public ResultExecutedContext ResultExecutedContext { get; }
+        public IFilterMetadata Filter { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(ResultExecutedContext), ResultExecutedContext),
+            2 => new KeyValuePair<string, object>(nameof(Filter), Filter),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class BeforeActionResult : EventData
+    {
+        public const string EventName = EventNamespace + nameof(BeforeActionResult);
+
+        public BeforeActionResult(ActionContext actionContext, IActionResult result)
+        {
+            ActionContext = actionContext;
+            Result = result;
+        }
+
+        public ActionContext ActionContext { get; }
+        public IActionResult Result { get; }
+
+        protected override int Count => 2;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionContext), ActionContext),
+            1 => new KeyValuePair<string, object>(nameof(Result), Result),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class AfterActionResult : EventData
+    {
+        public const string EventName = EventNamespace + nameof(AfterActionResult);
+
+        public AfterActionResult(ActionContext actionContext, IActionResult result)
+        {
+            ActionContext = actionContext;
+            Result = result;
+        }
+
+        public ActionContext ActionContext { get; }
+        public IActionResult Result { get; }
+
+        protected override int Count => 2;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionContext), ActionContext),
+            1 => new KeyValuePair<string, object>(nameof(Result), Result),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+}

src/Mvc/Mvc.Core/src/MvcCoreDiagnosticListenerExtensions.cs

@@ -5,6 +5,7 @@ using System.Collections.Generic;
 using System.Diagnostics;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc.Abstractions;
+using Microsoft.AspNetCore.Mvc.Diagnostics;
 using Microsoft.AspNetCore.Mvc.Filters;
 using Microsoft.AspNetCore.Routing;
 
@@ -13,7 +14,7 @@ namespace Microsoft.AspNetCore.Mvc
     // We're doing a lot of asserts here because these methods are really tedious to test and
     // highly dependent on the details of the invoker's state machine. Basically if we wrote the
     // obvious unit tests that would generate a lot of boilerplate and wouldn't cover the hard parts.
-    internal static class MvcCoreDiagnosticSourceExtensions
+    internal static class MvcCoreDiagnosticListenerExtensions
     {
         public static void BeforeAction(
             this DiagnosticListener diagnosticListener,
@@ -35,11 +36,11 @@ namespace Microsoft.AspNetCore.Mvc
 
         private static void BeforeActionImpl(DiagnosticListener diagnosticListener, ActionDescriptor actionDescriptor, HttpContext httpContext, RouteData routeData)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.BeforeAction"))
+            if (diagnosticListener.IsEnabled(Diagnostics.BeforeAction.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.BeforeAction",
+                    Diagnostics.BeforeAction.EventName,
-                    new { actionDescriptor, httpContext = httpContext, routeData = routeData });
+                    new BeforeAction(actionDescriptor, httpContext, routeData));
             }
         }
 
@@ -63,11 +64,11 @@ namespace Microsoft.AspNetCore.Mvc
 
         private static void AfterActionImpl(DiagnosticListener diagnosticListener, ActionDescriptor actionDescriptor, HttpContext httpContext, RouteData routeData)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.AfterAction"))
+            if (diagnosticListener.IsEnabled(Diagnostics.AfterAction.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.AfterAction",
+                    Diagnostics.AfterAction.EventName,
-                    new { actionDescriptor, httpContext = httpContext, routeData = routeData });
+                    new AfterAction(actionDescriptor, httpContext, routeData));
             }
         }
 
@@ -89,16 +90,15 @@ namespace Microsoft.AspNetCore.Mvc
 
         private static void BeforeOnAuthorizationAsyncImpl(DiagnosticListener diagnosticListener, AuthorizationFilterContext authorizationContext, IAsyncAuthorizationFilter filter)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.BeforeOnAuthorization"))
+            if (diagnosticListener.IsEnabled(Diagnostics.BeforeOnAuthorization.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.BeforeOnAuthorization",
+                    Diagnostics.BeforeOnAuthorization.EventName,
-                    new
+                    new BeforeOnAuthorization(
-                    {
+                        authorizationContext.ActionDescriptor,
-                        actionDescriptor = authorizationContext.ActionDescriptor,
+                        authorizationContext,
-                        authorizationContext = authorizationContext,
+                        filter
-                        filter = filter
+                    ));
-                    });
             }
         }
 
@@ -120,16 +120,15 @@ namespace Microsoft.AspNetCore.Mvc
 
         private static void AfterOnAuthorizationAsyncImpl(DiagnosticListener diagnosticListener, AuthorizationFilterContext authorizationContext, IAsyncAuthorizationFilter filter)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.AfterOnAuthorization"))
+            if (diagnosticListener.IsEnabled(Diagnostics.AfterOnAuthorization.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.AfterOnAuthorization",
+                    Diagnostics.AfterOnAuthorization.EventName,
-                    new
+                    new AfterOnAuthorization(
-                    {
+                        authorizationContext.ActionDescriptor,
-                        actionDescriptor = authorizationContext.ActionDescriptor,
+                        authorizationContext,
-                        authorizationContext = authorizationContext,
+                        filter
-                        filter = filter
+                    ));
-                    });
             }
         }
 
@@ -151,16 +150,15 @@ namespace Microsoft.AspNetCore.Mvc
 
         private static void BeforeOnAuthorizationImpl(DiagnosticListener diagnosticListener, AuthorizationFilterContext authorizationContext, IAuthorizationFilter filter)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.BeforeOnAuthorization"))
+            if (diagnosticListener.IsEnabled(Diagnostics.BeforeOnAuthorization.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.BeforeOnAuthorization",
+                    Diagnostics.BeforeOnAuthorization.EventName,
-                    new
+                    new BeforeOnAuthorization(
-                    {
+                        authorizationContext.ActionDescriptor,
-                        actionDescriptor = authorizationContext.ActionDescriptor,
+                        authorizationContext,
-                        authorizationContext = authorizationContext,
+                        filter
-                        filter = filter
+                    ));
-                    });
             }
         }
 
@@ -182,16 +180,15 @@ namespace Microsoft.AspNetCore.Mvc
 
         private static void AfterOnAuthorizationImpl(DiagnosticListener diagnosticListener, AuthorizationFilterContext authorizationContext, IAuthorizationFilter filter)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.AfterOnAuthorization"))
+            if (diagnosticListener.IsEnabled(Diagnostics.AfterOnAuthorization.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.AfterOnAuthorization",
+                    Diagnostics.AfterOnAuthorization.EventName,
-                    new
+                    new AfterOnAuthorization(
-                    {
+                        authorizationContext.ActionDescriptor,
-                        actionDescriptor = authorizationContext.ActionDescriptor,
+                        authorizationContext,
-                        authorizationContext = authorizationContext,
+                        filter
-                        filter = filter
+                    ));
-                    });
             }
         }
 
@@ -213,16 +210,15 @@ namespace Microsoft.AspNetCore.Mvc
 
         private static void BeforeOnResourceExecutionImpl(DiagnosticListener diagnosticListener, ResourceExecutingContext resourceExecutingContext, IAsyncResourceFilter filter)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.BeforeOnResourceExecution"))
+            if (diagnosticListener.IsEnabled(Diagnostics.BeforeOnResourceExecution.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.BeforeOnResourceExecution",
+                    Diagnostics.BeforeOnResourceExecution.EventName,
-                    new
+                    new BeforeOnResourceExecution(
-                    {
+                        resourceExecutingContext.ActionDescriptor,
-                        actionDescriptor = resourceExecutingContext.ActionDescriptor,
+                        resourceExecutingContext,
-                        resourceExecutingContext = resourceExecutingContext,
+                        filter
-                        filter = filter
+                    ));
-                    });
             }
         }
 
@@ -244,16 +240,15 @@ namespace Microsoft.AspNetCore.Mvc
 
         private static void AfterOnResourceExecutionImpl(DiagnosticListener diagnosticListener, ResourceExecutedContext resourceExecutedContext, IAsyncResourceFilter filter)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.AfterOnResourceExecution"))
+            if (diagnosticListener.IsEnabled(Diagnostics.AfterOnResourceExecution.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.AfterOnResourceExecution",
+                    Diagnostics.AfterOnResourceExecution.EventName,
-                    new
+                    new AfterOnResourceExecution(
-                    {
+                        resourceExecutedContext.ActionDescriptor,
-                        actionDescriptor = resourceExecutedContext.ActionDescriptor,
+                        resourceExecutedContext,
-                        resourceExecutedContext = resourceExecutedContext,
+                        filter
-                        filter = filter
+                    ));
-                    });
             }
         }
 
@@ -275,16 +270,15 @@ namespace Microsoft.AspNetCore.Mvc
 
         private static void BeforeOnResourceExecutingImpl(DiagnosticListener diagnosticListener, ResourceExecutingContext resourceExecutingContext, IResourceFilter filter)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.BeforeOnResourceExecuting"))
+            if (diagnosticListener.IsEnabled(Diagnostics.BeforeOnResourceExecuting.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.BeforeOnResourceExecuting",
+                    Diagnostics.BeforeOnResourceExecuting.EventName,
-                    new
+                    new BeforeOnResourceExecuting(
-                    {
+                        resourceExecutingContext.ActionDescriptor,
-                        actionDescriptor = resourceExecutingContext.ActionDescriptor,
+                        resourceExecutingContext,
-                        resourceExecutingContext = resourceExecutingContext,
+                        filter
-                        filter = filter
+                    ));
-                    });
             }
         }
 
@@ -306,16 +300,15 @@ namespace Microsoft.AspNetCore.Mvc
 
         private static void AfterOnResourceExecutingImpl(DiagnosticListener diagnosticListener, ResourceExecutingContext resourceExecutingContext, IResourceFilter filter)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.AfterOnResourceExecuting"))
+            if (diagnosticListener.IsEnabled(Diagnostics.AfterOnResourceExecuting.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.AfterOnResourceExecuting",
+                    Diagnostics.AfterOnResourceExecuting.EventName,
-                    new
+                    new AfterOnResourceExecuting(
-                    {
+                        resourceExecutingContext.ActionDescriptor,
-                        actionDescriptor = resourceExecutingContext.ActionDescriptor,
+                        resourceExecutingContext,
-                        resourceExecutingContext = resourceExecutingContext,
+                        filter
-                        filter = filter
+                    ));
-                    });
             }
         }
 
@@ -337,16 +330,15 @@ namespace Microsoft.AspNetCore.Mvc
 
         private static void BeforeOnResourceExecutedImpl(DiagnosticListener diagnosticListener, ResourceExecutedContext resourceExecutedContext, IResourceFilter filter)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.BeforeOnResourceExecuted"))
+            if (diagnosticListener.IsEnabled(Diagnostics.BeforeOnResourceExecuted.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.BeforeOnResourceExecuted",
+                    Diagnostics.BeforeOnResourceExecuted.EventName,
-                    new
+                    new BeforeOnResourceExecuted(
-                    {
+                        resourceExecutedContext.ActionDescriptor,
-                        actionDescriptor = resourceExecutedContext.ActionDescriptor,
+                        resourceExecutedContext,
-                        resourceExecutedContext = resourceExecutedContext,
+                        filter
-                        filter = filter
+                    ));
-                    });
             }
         }
 
@@ -368,16 +360,15 @@ namespace Microsoft.AspNetCore.Mvc
 
         private static void AfterOnResourceExecutedImpl(DiagnosticListener diagnosticListener, ResourceExecutedContext resourceExecutedContext, IResourceFilter filter)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.AfterOnResourceExecuted"))
+            if (diagnosticListener.IsEnabled(Diagnostics.AfterOnResourceExecuted.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.AfterOnResourceExecuted",
+                    Diagnostics.AfterOnResourceExecuted.EventName,
-                    new
+                    new AfterOnResourceExecuted(
-                    {
+                        resourceExecutedContext.ActionDescriptor,
-                        actionDescriptor = resourceExecutedContext.ActionDescriptor,
+                        resourceExecutedContext,
-                        resourceExecutedContext = resourceExecutedContext,
+                        filter
-                        filter = filter
+                    ));
-                    });
             }
         }
 
@@ -399,16 +390,15 @@ namespace Microsoft.AspNetCore.Mvc
 
         private static void BeforeOnExceptionAsyncImpl(DiagnosticListener diagnosticListener, ExceptionContext exceptionContext, IAsyncExceptionFilter filter)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.BeforeOnException"))
+            if (diagnosticListener.IsEnabled(Diagnostics.BeforeOnException.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.BeforeOnException",
+                    Diagnostics.BeforeOnException.EventName,
-                    new
+                    new BeforeOnException(
-                    {
+                        exceptionContext.ActionDescriptor,
-                        actionDescriptor = exceptionContext.ActionDescriptor,
+                        exceptionContext,
-                        exceptionContext = exceptionContext,
+                        filter
-                        filter = filter
+                    ));
-                    });
             }
         }
 
@@ -430,16 +420,15 @@ namespace Microsoft.AspNetCore.Mvc
 
         private static void AfterOnExceptionAsyncImpl(DiagnosticListener diagnosticListener, ExceptionContext exceptionContext, IAsyncExceptionFilter filter)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.AfterOnException"))
+            if (diagnosticListener.IsEnabled(Diagnostics.AfterOnException.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.AfterOnException",
+                    Diagnostics.AfterOnException.EventName,
-                    new
+                    new AfterOnException(
-                    {
+                        exceptionContext.ActionDescriptor,
-                        actionDescriptor = exceptionContext.ActionDescriptor,
+                        exceptionContext,
-                        exceptionContext = exceptionContext,
+                        filter
-                        filter = filter
+                    ));
-                    });
             }
         }
 
@@ -461,16 +450,15 @@ namespace Microsoft.AspNetCore.Mvc
 
         private static void BeforeOnExceptionImpl(DiagnosticListener diagnosticListener, ExceptionContext exceptionContext, IExceptionFilter filter)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.BeforeOnException"))
+            if (diagnosticListener.IsEnabled(Diagnostics.BeforeOnException.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.BeforeOnException",
+                    Diagnostics.BeforeOnException.EventName,
-                    new
+                    new BeforeOnException(
-                    {
+                        exceptionContext.ActionDescriptor,
-                        actionDescriptor = exceptionContext.ActionDescriptor,
+                        exceptionContext,
-                        exceptionContext = exceptionContext,
+                        filter
-                        filter = filter
+                    ));
-                    });
             }
         }
 
@@ -492,16 +480,15 @@ namespace Microsoft.AspNetCore.Mvc
 
         private static void AfterOnExceptionImpl(DiagnosticListener diagnosticListener, ExceptionContext exceptionContext, IExceptionFilter filter)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.AfterOnException"))
+            if (diagnosticListener.IsEnabled(Diagnostics.AfterOnException.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.AfterOnException",
+                    Diagnostics.AfterOnException.EventName,
-                    new
+                    new AfterOnException(
-                    {
+                        exceptionContext.ActionDescriptor,
-                        actionDescriptor = exceptionContext.ActionDescriptor,
+                        exceptionContext,
-                        exceptionContext = exceptionContext,
+                        filter
-                        filter = filter
+                    ));
-                    });
             }
         }
 
@@ -523,16 +510,15 @@ namespace Microsoft.AspNetCore.Mvc
 
         private static void BeforeOnActionExecutionImpl(DiagnosticListener diagnosticListener, ActionExecutingContext actionExecutingContext, IAsyncActionFilter filter)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.BeforeOnActionExecution"))
+            if (diagnosticListener.IsEnabled(Diagnostics.BeforeOnActionExecution.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.BeforeOnActionExecution",
+                    Diagnostics.BeforeOnActionExecution.EventName,
-                    new
+                    new BeforeOnActionExecution(
-                    {
+                        actionExecutingContext.ActionDescriptor,
-                        actionDescriptor = actionExecutingContext.ActionDescriptor,
+                        actionExecutingContext,
-                        actionExecutingContext = actionExecutingContext,
+                        filter
-                        filter = filter
+                    ));
-                    });
             }
         }
 
@@ -554,16 +540,15 @@ namespace Microsoft.AspNetCore.Mvc
 
         private static void AfterOnActionExecutionImpl(DiagnosticListener diagnosticListener, ActionExecutedContext actionExecutedContext, IAsyncActionFilter filter)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.AfterOnActionExecution"))
+            if (diagnosticListener.IsEnabled(Diagnostics.AfterOnActionExecution.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.AfterOnActionExecution",
+                    Diagnostics.AfterOnActionExecution.EventName,
-                    new
+                    new AfterOnActionExecution(
-                    {
+                        actionExecutedContext.ActionDescriptor,
-                        actionDescriptor = actionExecutedContext.ActionDescriptor,
+                        actionExecutedContext,
-                        actionExecutedContext = actionExecutedContext,
+                        filter
-                        filter = filter
+                    ));
-                    });
             }
         }
 
@@ -585,16 +570,15 @@ namespace Microsoft.AspNetCore.Mvc
 
         private static void BeforeOnActionExecutingImpl(DiagnosticListener diagnosticListener, ActionExecutingContext actionExecutingContext, IActionFilter filter)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.BeforeOnActionExecuting"))
+            if (diagnosticListener.IsEnabled(Diagnostics.BeforeOnActionExecuting.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.BeforeOnActionExecuting",
+                    Diagnostics.BeforeOnActionExecuting.EventName,
-                    new
+                    new BeforeOnActionExecuting(
-                    {
+                        actionExecutingContext.ActionDescriptor,
-                        actionDescriptor = actionExecutingContext.ActionDescriptor,
+                        actionExecutingContext,
-                        actionExecutingContext = actionExecutingContext,
+                        filter
-                        filter = filter
+                    ));
-                    });
             }
         }
 
@@ -616,16 +600,15 @@ namespace Microsoft.AspNetCore.Mvc
 
         private static void AfterOnActionExecutingImpl(DiagnosticListener diagnosticListener, ActionExecutingContext actionExecutingContext, IActionFilter filter)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.AfterOnActionExecuting"))
+            if (diagnosticListener.IsEnabled(Diagnostics.AfterOnActionExecuting.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.AfterOnActionExecuting",
+                    Diagnostics.AfterOnActionExecuting.EventName,
-                    new
+                    new AfterOnActionExecuting(
-                    {
+                        actionExecutingContext.ActionDescriptor,
-                        actionDescriptor = actionExecutingContext.ActionDescriptor,
+                        actionExecutingContext,
-                        actionExecutingContext = actionExecutingContext,
+                        filter
-                        filter = filter
+                    ));
-                    });
             }
         }
 
@@ -647,16 +630,15 @@ namespace Microsoft.AspNetCore.Mvc
 
         private static void BeforeOnActionExecutedImpl(DiagnosticListener diagnosticListener, ActionExecutedContext actionExecutedContext, IActionFilter filter)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.BeforeOnActionExecuted"))
+            if (diagnosticListener.IsEnabled(Diagnostics.BeforeOnActionExecuted.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.BeforeOnActionExecuted",
+                    Diagnostics.BeforeOnActionExecuted.EventName,
-                    new
+                    new BeforeOnActionExecuted(
-                    {
+                        actionExecutedContext.ActionDescriptor,
-                        actionDescriptor = actionExecutedContext.ActionDescriptor,
+                        actionExecutedContext,
-                        actionExecutedContext = actionExecutedContext,
+                        filter
-                        filter = filter
+                    ));
-                    });
             }
         }
 
@@ -678,23 +660,22 @@ namespace Microsoft.AspNetCore.Mvc
 
         private static void AfterOnActionExecutedImpl(DiagnosticListener diagnosticListener, ActionExecutedContext actionExecutedContext, IActionFilter filter)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.AfterOnActionExecuted"))
+            if (diagnosticListener.IsEnabled(Diagnostics.AfterOnActionExecuted.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.AfterOnActionExecuted",
+                    Diagnostics.AfterOnActionExecuted.EventName,
-                    new
+                    new AfterOnActionExecuted(
-                    {
+                        actionExecutedContext.ActionDescriptor,
-                        actionDescriptor = actionExecutedContext.ActionDescriptor,
+                        actionExecutedContext,
-                        actionExecutedContext = actionExecutedContext,
+                        filter
-                        filter = filter
+                    ));
-                    });
             }
         }
 
         public static void BeforeActionMethod(
             this DiagnosticListener diagnosticListener,
             ActionContext actionContext,
-            IDictionary<string, object> actionArguments,
+            IReadOnlyDictionary<string, object> actionArguments,
             object controller)
         {
             Debug.Assert(diagnosticListener != null);
@@ -709,25 +690,24 @@ namespace Microsoft.AspNetCore.Mvc
             }
         }
 
-        private static void BeforeActionMethodImpl(DiagnosticListener diagnosticListener, ActionContext actionContext, IDictionary<string, object> actionArguments, object controller)
+        private static void BeforeActionMethodImpl(DiagnosticListener diagnosticListener, ActionContext actionContext, IReadOnlyDictionary<string, object> actionArguments, object controller)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.BeforeActionMethod"))
+            if (diagnosticListener.IsEnabled(Diagnostics.BeforeActionMethod.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.BeforeActionMethod",
+                    Diagnostics.BeforeActionMethod.EventName,
-                    new
+                    new BeforeActionMethod(
-                    {
+                        actionContext,
-                        actionContext = actionContext,
+                        actionArguments,
-                        arguments = actionArguments,
+                        controller
-                        controller = controller
+                    ));
-                    });
             }
         }
 
         public static void AfterActionMethod(
             this DiagnosticListener diagnosticListener,
             ActionContext actionContext,
-            IDictionary<string, object> actionArguments,
+            IReadOnlyDictionary<string, object> actionArguments,
             object controller,
             IActionResult result)
         {
@@ -743,19 +723,18 @@ namespace Microsoft.AspNetCore.Mvc
             }
         }
 
-        private static void AfterActionMethodImpl(DiagnosticListener diagnosticListener, ActionContext actionContext, IDictionary<string, object> actionArguments, object controller, IActionResult result)
+        private static void AfterActionMethodImpl(DiagnosticListener diagnosticListener, ActionContext actionContext, IReadOnlyDictionary<string, object> actionArguments, object controller, IActionResult result)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.AfterActionMethod"))
+            if (diagnosticListener.IsEnabled(Diagnostics.AfterActionMethod.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.AfterActionMethod",
+                    Diagnostics.AfterActionMethod.EventName,
-                    new
+                    new AfterActionMethod(
-                    {
+                        actionContext,
-                        actionContext = actionContext,
+                        actionArguments,
-                        arguments = actionArguments,
+                        controller,
-                        controller = controller,
+                        result
-                        result = result
+                    ));
-                    });
             }
         }
 
@@ -777,16 +756,15 @@ namespace Microsoft.AspNetCore.Mvc
 
         private static void BeforeOnResultExecutionImpl(DiagnosticListener diagnosticListener, ResultExecutingContext resultExecutingContext, IAsyncResultFilter filter)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.BeforeOnResultExecution"))
+            if (diagnosticListener.IsEnabled(Diagnostics.BeforeOnResultExecution.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.BeforeOnResultExecution",
+                    Diagnostics.BeforeOnResultExecution.EventName,
-                    new
+                    new BeforeOnResultExecution(
-                    {
+                        resultExecutingContext.ActionDescriptor,
-                        actionDescriptor = resultExecutingContext.ActionDescriptor,
+                        resultExecutingContext,
-                        resultExecutingContext = resultExecutingContext,
+                        filter
-                        filter = filter
+                    ));
-                    });
             }
         }
 
@@ -808,16 +786,15 @@ namespace Microsoft.AspNetCore.Mvc
 
         private static void AfterOnResultExecutionImpl(DiagnosticListener diagnosticListener, ResultExecutedContext resultExecutedContext, IAsyncResultFilter filter)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.AfterOnResultExecution"))
+            if (diagnosticListener.IsEnabled(Diagnostics.AfterOnResultExecution.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.AfterOnResultExecution",
+                    Diagnostics.AfterOnResultExecution.EventName,
-                    new
+                    new AfterOnResultExecution(
-                    {
+                        resultExecutedContext.ActionDescriptor,
-                        actionDescriptor = resultExecutedContext.ActionDescriptor,
+                        resultExecutedContext,
-                        resultExecutedContext = resultExecutedContext,
+                        filter
-                        filter = filter
+                    ));
-                    });
             }
         }
 
@@ -839,16 +816,15 @@ namespace Microsoft.AspNetCore.Mvc
 
         private static void BeforeOnResultExecutingImpl(DiagnosticListener diagnosticListener, ResultExecutingContext resultExecutingContext, IResultFilter filter)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.BeforeOnResultExecuting"))
+            if (diagnosticListener.IsEnabled(Diagnostics.BeforeOnResultExecuting.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.BeforeOnResultExecuting",
+                    Diagnostics.BeforeOnResultExecuting.EventName,
-                    new
+                    new BeforeOnResultExecuting(
-                    {
+                        resultExecutingContext.ActionDescriptor,
-                        actionDescriptor = resultExecutingContext.ActionDescriptor,
+                        resultExecutingContext,
-                        resultExecutingContext = resultExecutingContext,
+                        filter
-                        filter = filter
+                    ));
-                    });
             }
         }
 
@@ -870,16 +846,15 @@ namespace Microsoft.AspNetCore.Mvc
 
         private static void AfterOnResultExecutingImpl(DiagnosticListener diagnosticListener, ResultExecutingContext resultExecutingContext, IResultFilter filter)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.AfterOnResultExecuting"))
+            if (diagnosticListener.IsEnabled(Diagnostics.AfterOnResultExecuting.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.AfterOnResultExecuting",
+                    Diagnostics.AfterOnResultExecuting.EventName,
-                    new
+                    new AfterOnResultExecuting(
-                    {
+                        resultExecutingContext.ActionDescriptor,
-                        actionDescriptor = resultExecutingContext.ActionDescriptor,
+                        resultExecutingContext,
-                        resultExecutingContext = resultExecutingContext,
+                        filter
-                        filter = filter
+                    ));
-                    });
             }
         }
 
@@ -901,16 +876,15 @@ namespace Microsoft.AspNetCore.Mvc
 
         private static void BeforeOnResultExecutedImpl(DiagnosticListener diagnosticListener, ResultExecutedContext resultExecutedContext, IResultFilter filter)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.BeforeOnResultExecuted"))
+            if (diagnosticListener.IsEnabled(Diagnostics.BeforeOnResultExecuted.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.BeforeOnResultExecuted",
+                    Diagnostics.BeforeOnResultExecuted.EventName,
-                    new
+                    new BeforeOnResultExecuted(
-                    {
+                        resultExecutedContext.ActionDescriptor,
-                        actionDescriptor = resultExecutedContext.ActionDescriptor,
+                        resultExecutedContext,
-                        resultExecutedContext = resultExecutedContext,
+                        filter
-                        filter = filter
+                    ));
-                    });
             }
         }
 
@@ -932,16 +906,15 @@ namespace Microsoft.AspNetCore.Mvc
 
         private static void AfterOnResultExecutedImpl(DiagnosticListener diagnosticListener, ResultExecutedContext resultExecutedContext, IResultFilter filter)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.AfterOnResultExecuted"))
+            if (diagnosticListener.IsEnabled(Diagnostics.AfterOnResultExecuted.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.AfterOnResultExecuted",
+                    Diagnostics.AfterOnResultExecuted.EventName,
-                    new
+                    new AfterOnResultExecuted(
-                    {
+                        resultExecutedContext.ActionDescriptor,
-                        actionDescriptor = resultExecutedContext.ActionDescriptor,
+                        resultExecutedContext,
-                        resultExecutedContext = resultExecutedContext,
+                        filter
-                        filter = filter
+                    ));
-                    });
             }
         }
 
@@ -963,11 +936,11 @@ namespace Microsoft.AspNetCore.Mvc
 
         private static void BeforeActionResultImpl(DiagnosticListener diagnosticListener, ActionContext actionContext, IActionResult result)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.BeforeActionResult"))
+            if (diagnosticListener.IsEnabled(Diagnostics.BeforeActionResult.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.BeforeActionResult",
+                    Diagnostics.BeforeActionResult.EventName,
-                    new { actionContext = actionContext, result = result });
+                    new BeforeActionResult(actionContext, result));
             }
         }
 
@@ -989,11 +962,11 @@ namespace Microsoft.AspNetCore.Mvc
 
         private static void AfterActionResultImpl(DiagnosticListener diagnosticListener, ActionContext actionContext, IActionResult result)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.AfterActionResult"))
+            if (diagnosticListener.IsEnabled(Diagnostics.AfterActionResult.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.AfterActionResult",
+                    Diagnostics.AfterActionResult.EventName,
-                    new { actionContext = actionContext, result = result });
+                    new AfterActionResult(actionContext, result));
             }
         }
     }

src/Mvc/Mvc.Razor/ref/Microsoft.AspNetCore.Mvc.Razor.netcoreapp3.0.cs

@@ -21,6 +21,31 @@ namespace Microsoft.AspNetCore.Mvc.ApplicationParts
         System.Collections.Generic.IEnumerable<Microsoft.AspNetCore.Razor.Hosting.RazorCompiledItem> CompiledItems { get; }
     }
 }
+namespace Microsoft.AspNetCore.Mvc.Diagnostics
+{
+    public sealed partial class AfterViewPage : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.Razor.AfterViewPage";
+        public AfterViewPage(Microsoft.AspNetCore.Mvc.Razor.IRazorPage page, Microsoft.AspNetCore.Mvc.Rendering.ViewContext viewContext, Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor actionDescriptor, Microsoft.AspNetCore.Http.HttpContext httpContext) { }
+        public Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Http.HttpContext HttpContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Razor.IRazorPage Page { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Rendering.ViewContext ViewContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+    }
+    public sealed partial class BeforeViewPage : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.Razor.BeforeViewPage";
+        public BeforeViewPage(Microsoft.AspNetCore.Mvc.Razor.IRazorPage page, Microsoft.AspNetCore.Mvc.Rendering.ViewContext viewContext, Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor actionDescriptor, Microsoft.AspNetCore.Http.HttpContext httpContext) { }
+        public Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Http.HttpContext HttpContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Razor.IRazorPage Page { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Rendering.ViewContext ViewContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+    }
+}
 namespace Microsoft.AspNetCore.Mvc.Razor
 {
     public partial class HelperResult : Microsoft.AspNetCore.Html.IHtmlContent

src/Mvc/Mvc.Razor/src/Diagnostics/MvcDiagnostics.cs

@@ -0,0 +1,74 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Mvc.Abstractions;
+using Microsoft.AspNetCore.Mvc.Razor;
+using Microsoft.AspNetCore.Mvc.Rendering;
+
+namespace Microsoft.AspNetCore.Mvc.Diagnostics
+{
+    public sealed class BeforeViewPage : EventData
+    {
+        public const string EventName = EventNamespace + 
+            "Razor." +
+            nameof(BeforeViewPage);
+
+        public BeforeViewPage(IRazorPage page, ViewContext viewContext, ActionDescriptor actionDescriptor, HttpContext httpContext)
+        {
+            Page = page;
+            ViewContext = viewContext;
+            ActionDescriptor = actionDescriptor;
+            HttpContext = httpContext;
+        }
+
+        public IRazorPage Page { get; }
+        public ViewContext ViewContext { get; }
+        public ActionDescriptor ActionDescriptor { get; }
+        public HttpContext HttpContext { get; }
+
+        protected override int Count => 4;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(Page), Page),
+            1 => new KeyValuePair<string, object>(nameof(ViewContext), ViewContext),
+            2 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            3 => new KeyValuePair<string, object>(nameof(HttpContext), HttpContext),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class AfterViewPage : EventData
+    {
+        public const string EventName = EventNamespace +
+            "Razor." +
+            nameof(AfterViewPage);
+
+        public AfterViewPage(IRazorPage page, ViewContext viewContext, ActionDescriptor actionDescriptor, HttpContext httpContext)
+        {
+            Page = page;
+            ViewContext = viewContext;
+            ActionDescriptor = actionDescriptor;
+            HttpContext = httpContext;
+        }
+
+        public IRazorPage Page { get; }
+        public ViewContext ViewContext { get; }
+        public ActionDescriptor ActionDescriptor { get; }
+        public HttpContext HttpContext { get; }
+
+        protected override int Count => 4;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(Page), Page),
+            1 => new KeyValuePair<string, object>(nameof(ViewContext), ViewContext),
+            2 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            3 => new KeyValuePair<string, object>(nameof(HttpContext), HttpContext),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+}

src/Mvc/Mvc.Razor/src/MvcRazorDiagnosticListenerExtensions.cs

@@ -3,10 +3,12 @@
 
 using System.Diagnostics;
 using Microsoft.AspNetCore.Mvc.Rendering;
+using Microsoft.AspNetCore.Mvc.Diagnostics;
+using Microsoft.AspNetCore.Http;
 
 namespace Microsoft.AspNetCore.Mvc.Razor
 {
-    internal static class MvcRazorDiagnosticSourceExtensions
+    internal static class MvcRazorDiagnosticListenerExtensions
     {
         public static void BeforeViewPage(
             this DiagnosticListener diagnosticListener,
@@ -25,17 +27,16 @@ namespace Microsoft.AspNetCore.Mvc.Razor
             IRazorPage page,
             ViewContext viewContext)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.Razor.BeforeViewPage"))
+            if (diagnosticListener.IsEnabled(Diagnostics.BeforeViewPage.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.Razor.BeforeViewPage",
+                    Diagnostics.BeforeViewPage.EventName,
-                    new
+                    new BeforeViewPage(
-                    {
+                        page,
-                        page = page,
+                        viewContext,
-                        viewContext = viewContext,
+                        viewContext.ActionDescriptor,
-                        actionDescriptor = viewContext.ActionDescriptor,
+                        viewContext.HttpContext
-                        httpContext = viewContext.HttpContext,
+                    ));
-                    });
             }
         }
 
@@ -56,17 +57,16 @@ namespace Microsoft.AspNetCore.Mvc.Razor
             IRazorPage page,
             ViewContext viewContext)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.Razor.AfterViewPage"))
+            if (diagnosticListener.IsEnabled(Diagnostics.AfterViewPage.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.Razor.AfterViewPage",
+                    Diagnostics.AfterViewPage.EventName,
-                    new
+                    new AfterViewPage(
-                    {
+                        page,
-                        page = page,
+                        viewContext,
-                        viewContext = viewContext,
+                        viewContext.ActionDescriptor,
-                        actionDescriptor = viewContext.ActionDescriptor,
+                        viewContext.HttpContext
-                        httpContext = viewContext.HttpContext,
+                    ));
-                    });
             }
         }
     }

src/Mvc/Mvc.Razor/src/RazorPage.cs

@@ -276,37 +276,12 @@ namespace Microsoft.AspNetCore.Mvc.Razor
 
         public override void BeginContext(int position, int length, bool isLiteral)
         {
-            const string BeginContextEvent = "Microsoft.AspNetCore.Mvc.Razor.BeginInstrumentationContext";
+            // noop
-
-            if (DiagnosticSource?.IsEnabled(BeginContextEvent) == true)
-            {
-                DiagnosticSource.Write(
-                    BeginContextEvent,
-                    new
-                    {
-                        httpContext = Context,
-                        path = Path,
-                        position = position,
-                        length = length,
-                        isLiteral = isLiteral,
-                    });
-            }
         }
 
         public override void EndContext()
         {
-            const string EndContextEvent = "Microsoft.AspNetCore.Mvc.Razor.EndInstrumentationContext";
+            // noop
-
-            if (DiagnosticSource?.IsEnabled(EndContextEvent) == true)
-            {
-                DiagnosticSource.Write(
-                    EndContextEvent,
-                    new
-                    {
-                        httpContext = Context,
-                        path = Path,
-                    });
-            }
         }
 
         private void EnsureMethodCanBeInvoked(string methodName)

src/Mvc/Mvc.Razor/test/RazorPageActivatorTest.cs

@@ -26,7 +26,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor
     {
         public RazorPageActivatorTest()
         {
-            DiagnosticSource = new DiagnosticListener("Microsoft.AspNetCore");
+            DiagnosticListener = new DiagnosticListener("Microsoft.AspNetCore");
             HtmlEncoder = new HtmlTestEncoder();
             JsonHelper = Mock.Of<IJsonHelper>();
             MetadataProvider = new EmptyModelMetadataProvider();
@@ -34,7 +34,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor
             UrlHelperFactory = new UrlHelperFactory();
         }
 
-        private DiagnosticSource DiagnosticSource { get; }
+        private DiagnosticListener DiagnosticListener { get; }
 
         private HtmlEncoder HtmlEncoder { get; }
 
@@ -62,7 +62,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor
             activator.Activate(instance, viewContext);
 
             // Assert
-            Assert.Same(DiagnosticSource, instance.DiagnosticSource);
+            Assert.Same(DiagnosticListener, instance.DiagnosticSource);
             Assert.Same(HtmlEncoder, instance.HtmlEncoder);
             Assert.Same(JsonHelper, instance.Json);
             Assert.Same(urlHelper, instance.Url);
@@ -97,7 +97,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor
             activator.Activate(instance, viewContext);
 
             // Assert
-            Assert.Same(DiagnosticSource, instance.DiagnosticSource);
+            Assert.Same(DiagnosticListener, instance.DiagnosticSource);
             Assert.Same(HtmlEncoder, instance.HtmlEncoder);
 
             // When we don't have a model property, the activator will just leave ViewData alone.
@@ -124,7 +124,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor
             activator.Activate(instance, viewContext);
 
             // Assert
-            Assert.Same(DiagnosticSource, instance.DiagnosticSource);
+            Assert.Same(DiagnosticListener, instance.DiagnosticSource);
             Assert.Same(HtmlEncoder, instance.HtmlEncoder);
             Assert.Same(JsonHelper, instance.Json);
             Assert.Same(urlHelper, instance.Url);
@@ -229,7 +229,7 @@ namespace Microsoft.AspNetCore.Mvc.Razor
 
         private RazorPageActivator CreateActivator()
         {
-            return new RazorPageActivator(MetadataProvider, UrlHelperFactory, JsonHelper, DiagnosticSource, HtmlEncoder, ModelExpressionProvider);
+            return new RazorPageActivator(MetadataProvider, UrlHelperFactory, JsonHelper, DiagnosticListener, HtmlEncoder, ModelExpressionProvider);
         }
 
         private ViewContext CreateViewContext(ViewDataDictionary viewData = null)

src/Mvc/Mvc.Razor/test/RazorPageTest.cs

@@ -948,216 +948,6 @@ namespace Microsoft.AspNetCore.Mvc.Razor
             Assert.Same(HtmlString.Empty, actual);
         }
 
-        [Fact]
-        public async Task WriteAttribute_WritesBeginAndEndEvents_ToDiagnosticSource()
-        {
-            // Arrange
-            var path = "path-to-page";
-            var page = CreatePage(p =>
-            {
-                p.HtmlEncoder = new HtmlTestEncoder();
-                p.BeginWriteAttribute("href", "prefix", 0, "suffix", 34, 2);
-                p.WriteAttributeValue("prefix", 0, "attr1-value", 8, 14, true);
-                p.WriteAttributeValue("prefix2", 22, "attr2", 29, 5, false);
-                p.EndWriteAttribute();
-            });
-            page.Path = path;
-            var adapter = new TestDiagnosticListener();
-            var diagnosticListener = new DiagnosticListener("Microsoft.AspNetCore.Mvc.Razor");
-            diagnosticListener.SubscribeWithAdapter(adapter);
-            page.DiagnosticSource = diagnosticListener;
-
-            // Act
-            await page.ExecuteAsync();
-
-            // Assert
-            Func<object, TestDiagnosticListener.BeginPageInstrumentationData> assertStartEvent = data =>
-            {
-                var beginEvent = Assert.IsType<TestDiagnosticListener.BeginPageInstrumentationData>(data);
-                Assert.NotNull(beginEvent.HttpContext);
-                Assert.Equal(path, beginEvent.Path);
-
-                return beginEvent;
-            };
-
-            Action<object> assertEndEvent = data =>
-            {
-                var endEvent = Assert.IsType<TestDiagnosticListener.EndPageInstrumentationData>(data);
-                Assert.NotNull(endEvent.HttpContext);
-                Assert.Equal(path, endEvent.Path);
-            };
-
-            Assert.Collection(adapter.PageInstrumentationData,
-                data =>
-                {
-                    var beginEvent = assertStartEvent(data);
-                    Assert.Equal(0, beginEvent.Position);
-                    Assert.Equal(6, beginEvent.Length);
-                    Assert.True(beginEvent.IsLiteral);
-                },
-                assertEndEvent,
-                data =>
-                {
-                    var beginEvent = assertStartEvent(data);
-                    Assert.Equal(0, beginEvent.Position);
-                    Assert.Equal(6, beginEvent.Length);
-                    Assert.True(beginEvent.IsLiteral);
-                },
-                assertEndEvent,
-                data =>
-                {
-                    var beginEvent = assertStartEvent(data);
-                    Assert.Equal(8, beginEvent.Position);
-                    Assert.Equal(14, beginEvent.Length);
-                    Assert.True(beginEvent.IsLiteral);
-                },
-                assertEndEvent,
-                data =>
-                {
-                    var beginEvent = assertStartEvent(data);
-                    Assert.Equal(22, beginEvent.Position);
-                    Assert.Equal(7, beginEvent.Length);
-                    Assert.True(beginEvent.IsLiteral);
-                },
-                assertEndEvent,
-                data =>
-                {
-                    var beginEvent = assertStartEvent(data);
-                    Assert.Equal(29, beginEvent.Position);
-                    Assert.Equal(5, beginEvent.Length);
-                    Assert.False(beginEvent.IsLiteral);
-                },
-                assertEndEvent,
-                data =>
-                {
-                    var beginEvent = assertStartEvent(data);
-                    Assert.Equal(34, beginEvent.Position);
-                    Assert.Equal(6, beginEvent.Length);
-                    Assert.True(beginEvent.IsLiteral);
-                },
-                assertEndEvent);
-        }
-
-        [Fact]
-        public async Task WriteAttribute_WithBoolValue_WritesBeginAndEndEvents_ToDiagnosticSource()
-        {
-            // Arrange
-            var path = "some-path";
-            var page = CreatePage(p =>
-            {
-                p.HtmlEncoder = new HtmlTestEncoder();
-                p.BeginWriteAttribute("href", "prefix", 0, "suffix", 10, 1);
-                p.WriteAttributeValue("", 6, "true", 6, 4, false);
-                p.EndWriteAttribute();
-            });
-            page.Path = path;
-            var adapter = new TestDiagnosticListener();
-            var diagnosticListener = new DiagnosticListener("Microsoft.AspNetCore.Mvc.Razor");
-            diagnosticListener.SubscribeWithAdapter(adapter);
-            page.DiagnosticSource = diagnosticListener;
-
-            // Act
-            await page.ExecuteAsync();
-
-            // Assert
-            Func<object, TestDiagnosticListener.BeginPageInstrumentationData> assertStartEvent = data =>
-            {
-                var beginEvent = Assert.IsType<TestDiagnosticListener.BeginPageInstrumentationData>(data);
-                Assert.NotNull(beginEvent.HttpContext);
-                Assert.Equal(path, beginEvent.Path);
-
-                return beginEvent;
-            };
-
-            Action<object> assertEndEvent = data =>
-            {
-                var endEvent = Assert.IsType<TestDiagnosticListener.EndPageInstrumentationData>(data);
-                Assert.NotNull(endEvent.HttpContext);
-                Assert.Equal(path, endEvent.Path);
-            };
-
-            Assert.Collection(adapter.PageInstrumentationData,
-                data =>
-                {
-                    var beginEvent = assertStartEvent(data);
-                    Assert.Equal(0, beginEvent.Position);
-                    Assert.Equal(6, beginEvent.Length);
-                    Assert.True(beginEvent.IsLiteral);
-                },
-                assertEndEvent,
-                data =>
-                {
-                    var beginEvent = assertStartEvent(data);
-                    Assert.Equal(6, beginEvent.Position);
-                    Assert.Equal(4, beginEvent.Length);
-                    Assert.False(beginEvent.IsLiteral);
-                },
-                assertEndEvent,
-                data =>
-                {
-                    var beginEvent = assertStartEvent(data);
-                    Assert.Equal(10, beginEvent.Position);
-                    Assert.Equal(6, beginEvent.Length);
-                    Assert.True(beginEvent.IsLiteral);
-                },
-                assertEndEvent);
-        }
-
-        [Fact]
-        public async Task WriteAttribute_WritesBeginAndEndEvents_ToDiagnosticSource_OnPrefixAndSuffixValues()
-        {
-            // Arrange
-            var path = "some-path";
-            var page = CreatePage(p =>
-            {
-                p.BeginWriteAttribute("href", "prefix", 0, "tail", 7, 0);
-                p.EndWriteAttribute();
-            });
-            page.Path = path;
-            var adapter = new TestDiagnosticListener();
-            var diagnosticListener = new DiagnosticListener("Microsoft.AspNetCore.Mvc.Razor");
-            diagnosticListener.SubscribeWithAdapter(adapter);
-            page.DiagnosticSource = diagnosticListener;
-
-            // Act
-            await page.ExecuteAsync();
-
-            // Assert
-            Func<object, TestDiagnosticListener.BeginPageInstrumentationData> assertStartEvent = data =>
-            {
-                var beginEvent = Assert.IsType<TestDiagnosticListener.BeginPageInstrumentationData>(data);
-                Assert.NotNull(beginEvent.HttpContext);
-                Assert.Equal(path, beginEvent.Path);
-
-                return beginEvent;
-            };
-
-            Action<object> assertEndEvent = data =>
-            {
-                var endEvent = Assert.IsType<TestDiagnosticListener.EndPageInstrumentationData>(data);
-                Assert.NotNull(endEvent.HttpContext);
-                Assert.Equal(path, endEvent.Path);
-            };
-
-            Assert.Collection(adapter.PageInstrumentationData,
-                data =>
-                {
-                    var beginEvent = assertStartEvent(data);
-                    Assert.Equal(0, beginEvent.Position);
-                    Assert.Equal(6, beginEvent.Length);
-                    Assert.True(beginEvent.IsLiteral);
-                },
-                assertEndEvent,
-                data =>
-                {
-                    var beginEvent = assertStartEvent(data);
-                    Assert.Equal(7, beginEvent.Position);
-                    Assert.Equal(4, beginEvent.Length);
-                    Assert.True(beginEvent.IsLiteral);
-                },
-                assertEndEvent);
-        }
-
         public static TheoryData AddHtmlAttributeValues_ValueData
         {
             get

src/Mvc/Mvc.RazorPages/ref/Microsoft.AspNetCore.Mvc.RazorPages.netcoreapp3.0.cs

@@ -143,6 +143,132 @@ namespace Microsoft.AspNetCore.Mvc.ApplicationModels
         protected virtual bool ShouldApply(Microsoft.AspNetCore.Mvc.ApplicationModels.PageRouteModel action) { throw null; }
     }
 }
+namespace Microsoft.AspNetCore.Mvc.Diagnostics
+{
+    public sealed partial class AfterHandlerMethod : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.AfterHandlerMethod";
+        public AfterHandlerMethod(Microsoft.AspNetCore.Mvc.ActionContext actionContext, System.Collections.Generic.IReadOnlyDictionary<string, object> arguments, Microsoft.AspNetCore.Mvc.RazorPages.Infrastructure.HandlerMethodDescriptor handlerMethodDescriptor, object instance, Microsoft.AspNetCore.Mvc.IActionResult result) { }
+        public Microsoft.AspNetCore.Mvc.ActionContext ActionContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public System.Collections.Generic.IReadOnlyDictionary<string, object> Arguments { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.RazorPages.Infrastructure.HandlerMethodDescriptor HandlerMethodDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public object Instance { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.IActionResult Result { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+    }
+    public sealed partial class AfterOnPageHandlerExecuted : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.AfterOnPageHandlerExecuted";
+        public AfterOnPageHandlerExecuted(Microsoft.AspNetCore.Mvc.RazorPages.CompiledPageActionDescriptor actionDescriptor, Microsoft.AspNetCore.Mvc.Filters.PageHandlerExecutedContext handlerExecutedContext, Microsoft.AspNetCore.Mvc.Filters.IPageFilter filter) { }
+        public Microsoft.AspNetCore.Mvc.RazorPages.CompiledPageActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.IPageFilter Filter { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.PageHandlerExecutedContext HandlerExecutedContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+    }
+    public sealed partial class AfterOnPageHandlerExecuting : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.AfterOnPageHandlerExecuting";
+        public AfterOnPageHandlerExecuting(Microsoft.AspNetCore.Mvc.RazorPages.CompiledPageActionDescriptor actionDescriptor, Microsoft.AspNetCore.Mvc.Filters.PageHandlerExecutingContext handlerExecutingContext, Microsoft.AspNetCore.Mvc.Filters.IPageFilter filter) { }
+        public Microsoft.AspNetCore.Mvc.RazorPages.CompiledPageActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.IPageFilter Filter { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.PageHandlerExecutingContext HandlerExecutingContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+    }
+    public sealed partial class AfterOnPageHandlerExecution : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.AfterOnPageHandlerExecution";
+        public AfterOnPageHandlerExecution(Microsoft.AspNetCore.Mvc.RazorPages.CompiledPageActionDescriptor actionDescriptor, Microsoft.AspNetCore.Mvc.Filters.PageHandlerExecutedContext handlerExecutedContext, Microsoft.AspNetCore.Mvc.Filters.IAsyncPageFilter filter) { }
+        public Microsoft.AspNetCore.Mvc.RazorPages.CompiledPageActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.IAsyncPageFilter Filter { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.PageHandlerExecutedContext HandlerExecutedContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+    }
+    public sealed partial class AfterOnPageHandlerSelected : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.AfterOnPageHandlerSelected";
+        public AfterOnPageHandlerSelected(Microsoft.AspNetCore.Mvc.RazorPages.CompiledPageActionDescriptor actionDescriptor, Microsoft.AspNetCore.Mvc.Filters.PageHandlerSelectedContext handlerSelectedContext, Microsoft.AspNetCore.Mvc.Filters.IPageFilter filter) { }
+        public Microsoft.AspNetCore.Mvc.RazorPages.CompiledPageActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.IPageFilter Filter { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.PageHandlerSelectedContext HandlerSelectedContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+    }
+    public sealed partial class AfterOnPageHandlerSelection : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.AfterOnPageHandlerSelection";
+        public AfterOnPageHandlerSelection(Microsoft.AspNetCore.Mvc.RazorPages.CompiledPageActionDescriptor actionDescriptor, Microsoft.AspNetCore.Mvc.Filters.PageHandlerSelectedContext handlerSelectedContext, Microsoft.AspNetCore.Mvc.Filters.IAsyncPageFilter filter) { }
+        public Microsoft.AspNetCore.Mvc.RazorPages.CompiledPageActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.IAsyncPageFilter Filter { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.PageHandlerSelectedContext HandlerSelectedContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+    }
+    public sealed partial class BeforeHandlerMethod : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.BeforeHandlerMethod";
+        public BeforeHandlerMethod(Microsoft.AspNetCore.Mvc.ActionContext actionContext, System.Collections.Generic.IReadOnlyDictionary<string, object> arguments, Microsoft.AspNetCore.Mvc.RazorPages.Infrastructure.HandlerMethodDescriptor handlerMethodDescriptor, object instance) { }
+        public Microsoft.AspNetCore.Mvc.ActionContext ActionContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public System.Collections.Generic.IReadOnlyDictionary<string, object> Arguments { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.RazorPages.Infrastructure.HandlerMethodDescriptor HandlerMethodDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public object Instance { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+    }
+    public sealed partial class BeforeOnPageHandlerExecuted : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.BeforeOnPageHandlerExecuted";
+        public BeforeOnPageHandlerExecuted(Microsoft.AspNetCore.Mvc.RazorPages.CompiledPageActionDescriptor actionDescriptor, Microsoft.AspNetCore.Mvc.Filters.PageHandlerExecutedContext handlerExecutedContext, Microsoft.AspNetCore.Mvc.Filters.IPageFilter filter) { }
+        public Microsoft.AspNetCore.Mvc.RazorPages.CompiledPageActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.IPageFilter Filter { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.PageHandlerExecutedContext HandlerExecutedContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+    }
+    public sealed partial class BeforeOnPageHandlerExecuting : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.BeforeOnPageHandlerExecuting";
+        public BeforeOnPageHandlerExecuting(Microsoft.AspNetCore.Mvc.RazorPages.CompiledPageActionDescriptor actionDescriptor, Microsoft.AspNetCore.Mvc.Filters.PageHandlerExecutingContext handlerExecutingContext, Microsoft.AspNetCore.Mvc.Filters.IPageFilter filter) { }
+        public Microsoft.AspNetCore.Mvc.RazorPages.CompiledPageActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.IPageFilter Filter { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.PageHandlerExecutingContext HandlerExecutingContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+    }
+    public sealed partial class BeforeOnPageHandlerExecution : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.BeforeOnPageHandlerExecution";
+        public BeforeOnPageHandlerExecution(Microsoft.AspNetCore.Mvc.RazorPages.CompiledPageActionDescriptor actionDescriptor, Microsoft.AspNetCore.Mvc.Filters.PageHandlerExecutingContext handlerExecutionContext, Microsoft.AspNetCore.Mvc.Filters.IAsyncPageFilter filter) { }
+        public Microsoft.AspNetCore.Mvc.RazorPages.CompiledPageActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.IAsyncPageFilter Filter { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.PageHandlerExecutingContext HandlerExecutionContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+    }
+    public sealed partial class BeforeOnPageHandlerSelected : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.BeforeOnPageHandlerSelected";
+        public BeforeOnPageHandlerSelected(Microsoft.AspNetCore.Mvc.RazorPages.CompiledPageActionDescriptor actionDescriptor, Microsoft.AspNetCore.Mvc.Filters.PageHandlerSelectedContext handlerSelectedContext, Microsoft.AspNetCore.Mvc.Filters.IPageFilter filter) { }
+        public Microsoft.AspNetCore.Mvc.RazorPages.CompiledPageActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.IPageFilter Filter { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.PageHandlerSelectedContext HandlerSelectedContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+    }
+    public sealed partial class BeforeOnPageHandlerSelection : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.BeforeOnPageHandlerSelection";
+        public BeforeOnPageHandlerSelection(Microsoft.AspNetCore.Mvc.RazorPages.CompiledPageActionDescriptor actionDescriptor, Microsoft.AspNetCore.Mvc.Filters.PageHandlerSelectedContext handlerSelectedContext, Microsoft.AspNetCore.Mvc.Filters.IAsyncPageFilter filter) { }
+        public Microsoft.AspNetCore.Mvc.RazorPages.CompiledPageActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.IAsyncPageFilter Filter { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Filters.PageHandlerSelectedContext HandlerSelectedContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+    }
+}
 namespace Microsoft.AspNetCore.Mvc.Filters
 {
     public partial interface IAsyncPageFilter : Microsoft.AspNetCore.Mvc.Filters.IFilterMetadata

src/Mvc/Mvc.RazorPages/src/Diagnostics/MvcDiagnostics.cs

@@ -0,0 +1,333 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using Microsoft.AspNetCore.Mvc.Filters;
+using Microsoft.AspNetCore.Mvc.RazorPages.Infrastructure;
+using Microsoft.AspNetCore.Mvc.RazorPages;
+using Microsoft.AspNetCore.Http;
+
+namespace Microsoft.AspNetCore.Mvc.Diagnostics
+{
+    public sealed class BeforeHandlerMethod : EventData
+    {
+        public const string EventName = EventNamespace + nameof(BeforeHandlerMethod);
+
+        public BeforeHandlerMethod(ActionContext actionContext, IReadOnlyDictionary<string, object> arguments, HandlerMethodDescriptor handlerMethodDescriptor, object instance)
+        {
+            ActionContext = actionContext;
+            Arguments = arguments;
+            HandlerMethodDescriptor = handlerMethodDescriptor;
+            Instance = instance;
+        }
+
+        public ActionContext ActionContext { get; }
+        public IReadOnlyDictionary<string, object> Arguments { get; }
+        public HandlerMethodDescriptor HandlerMethodDescriptor { get; }
+        public object Instance { get; }
+
+        protected override int Count => 4;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionContext), ActionContext),
+            1 => new KeyValuePair<string, object>(nameof(Arguments), Arguments),
+            2 => new KeyValuePair<string, object>(nameof(HandlerMethodDescriptor), HandlerMethodDescriptor),
+            3 => new KeyValuePair<string, object>(nameof(Instance), Instance),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class AfterHandlerMethod : EventData
+    {
+        public const string EventName = EventNamespace + nameof(AfterHandlerMethod);
+
+        public AfterHandlerMethod(ActionContext actionContext, IReadOnlyDictionary<string, object> arguments, HandlerMethodDescriptor handlerMethodDescriptor, object instance, IActionResult result)
+        {
+            ActionContext = actionContext;
+            Arguments = arguments;
+            HandlerMethodDescriptor = handlerMethodDescriptor;
+            Instance = instance;
+            Result = result;
+        }
+
+        public ActionContext ActionContext { get; }
+        public IReadOnlyDictionary<string, object> Arguments { get; }
+        public HandlerMethodDescriptor HandlerMethodDescriptor { get; }
+        public object Instance { get; }
+        public IActionResult Result { get; }
+
+        protected override int Count => 5;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionContext), ActionContext),
+            1 => new KeyValuePair<string, object>(nameof(Arguments), Arguments),
+            2 => new KeyValuePair<string, object>(nameof(HandlerMethodDescriptor), HandlerMethodDescriptor),
+            3 => new KeyValuePair<string, object>(nameof(Instance), Instance),
+            4 => new KeyValuePair<string, object>(nameof(Result), Result),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class BeforeOnPageHandlerExecution : EventData
+    {
+        public const string EventName = EventNamespace + nameof(BeforeOnPageHandlerExecution);
+
+        public BeforeOnPageHandlerExecution(CompiledPageActionDescriptor actionDescriptor, PageHandlerExecutingContext handlerExecutionContext, IAsyncPageFilter filter)
+        {
+            ActionDescriptor = actionDescriptor;
+            HandlerExecutionContext = handlerExecutionContext;
+            Filter = filter;
+        }
+
+        public CompiledPageActionDescriptor ActionDescriptor { get; }
+        public PageHandlerExecutingContext HandlerExecutionContext { get; }
+        public IAsyncPageFilter Filter { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(HandlerExecutionContext), HandlerExecutionContext),
+            2 => new KeyValuePair<string, object>(nameof(Filter), Filter),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class AfterOnPageHandlerExecution : EventData
+    {
+        public const string EventName = EventNamespace + nameof(AfterOnPageHandlerExecution);
+
+        public AfterOnPageHandlerExecution(CompiledPageActionDescriptor actionDescriptor, PageHandlerExecutedContext handlerExecutedContext, IAsyncPageFilter filter)
+        {
+            ActionDescriptor = actionDescriptor;
+            HandlerExecutedContext = handlerExecutedContext;
+            Filter = filter;
+        }
+
+        public CompiledPageActionDescriptor ActionDescriptor { get; }
+        public PageHandlerExecutedContext HandlerExecutedContext { get; }
+        public IAsyncPageFilter Filter { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(HandlerExecutedContext), HandlerExecutedContext),
+            2 => new KeyValuePair<string, object>(nameof(Filter), Filter),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class BeforeOnPageHandlerExecuting : EventData
+    {
+        public const string EventName = EventNamespace + nameof(BeforeOnPageHandlerExecuting);
+
+        public BeforeOnPageHandlerExecuting(CompiledPageActionDescriptor actionDescriptor, PageHandlerExecutingContext handlerExecutingContext, IPageFilter filter)
+        {
+            ActionDescriptor = actionDescriptor;
+            HandlerExecutingContext = handlerExecutingContext;
+            Filter = filter;
+        }
+
+        public CompiledPageActionDescriptor ActionDescriptor { get; }
+        public PageHandlerExecutingContext HandlerExecutingContext { get; }
+        public IPageFilter Filter { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(HandlerExecutingContext), HandlerExecutingContext),
+            2 => new KeyValuePair<string, object>(nameof(Filter), Filter),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class AfterOnPageHandlerExecuting : EventData
+    {
+        public const string EventName = EventNamespace + nameof(AfterOnPageHandlerExecuting);
+
+        public AfterOnPageHandlerExecuting(CompiledPageActionDescriptor actionDescriptor, PageHandlerExecutingContext handlerExecutingContext, IPageFilter filter)
+        {
+            ActionDescriptor = actionDescriptor;
+            HandlerExecutingContext = handlerExecutingContext;
+            Filter = filter;
+        }
+
+        public CompiledPageActionDescriptor ActionDescriptor { get; }
+        public PageHandlerExecutingContext HandlerExecutingContext { get; }
+        public IPageFilter Filter { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(HandlerExecutingContext), HandlerExecutingContext),
+            2 => new KeyValuePair<string, object>(nameof(Filter), Filter),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class BeforeOnPageHandlerExecuted : EventData
+    {
+        public const string EventName = EventNamespace + nameof(BeforeOnPageHandlerExecuted);
+
+        public BeforeOnPageHandlerExecuted(CompiledPageActionDescriptor actionDescriptor, PageHandlerExecutedContext handlerExecutedContext, IPageFilter filter)
+        {
+            ActionDescriptor = actionDescriptor;
+            HandlerExecutedContext = handlerExecutedContext;
+            Filter = filter;
+        }
+
+        public CompiledPageActionDescriptor ActionDescriptor { get; }
+        public PageHandlerExecutedContext HandlerExecutedContext { get; }
+        public IPageFilter Filter { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(HandlerExecutedContext), HandlerExecutedContext),
+            2 => new KeyValuePair<string, object>(nameof(Filter), Filter),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class AfterOnPageHandlerExecuted : EventData
+    {
+        public const string EventName = EventNamespace + nameof(AfterOnPageHandlerExecuted);
+
+        public AfterOnPageHandlerExecuted(CompiledPageActionDescriptor actionDescriptor, PageHandlerExecutedContext handlerExecutedContext, IPageFilter filter)
+        {
+            ActionDescriptor = actionDescriptor;
+            HandlerExecutedContext = handlerExecutedContext;
+            Filter = filter;
+        }
+
+        public CompiledPageActionDescriptor ActionDescriptor { get; }
+        public PageHandlerExecutedContext HandlerExecutedContext { get; }
+        public IPageFilter Filter { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(HandlerExecutedContext), HandlerExecutedContext),
+            2 => new KeyValuePair<string, object>(nameof(Filter), Filter),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class BeforeOnPageHandlerSelection : EventData
+    {
+        public const string EventName = EventNamespace + nameof(BeforeOnPageHandlerSelection);
+
+        public BeforeOnPageHandlerSelection(CompiledPageActionDescriptor actionDescriptor, PageHandlerSelectedContext handlerSelectedContext, IAsyncPageFilter filter)
+        {
+            ActionDescriptor = actionDescriptor;
+            HandlerSelectedContext = handlerSelectedContext;
+            Filter = filter;
+        }
+
+        public CompiledPageActionDescriptor ActionDescriptor { get; }
+        public PageHandlerSelectedContext HandlerSelectedContext { get; }
+        public IAsyncPageFilter Filter { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(HandlerSelectedContext), HandlerSelectedContext),
+            2 => new KeyValuePair<string, object>(nameof(Filter), Filter),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class AfterOnPageHandlerSelection : EventData
+    {
+        public const string EventName = EventNamespace + nameof(AfterOnPageHandlerSelection);
+
+        public AfterOnPageHandlerSelection(CompiledPageActionDescriptor actionDescriptor, PageHandlerSelectedContext handlerSelectedContext, IAsyncPageFilter filter)
+        {
+            ActionDescriptor = actionDescriptor;
+            HandlerSelectedContext = handlerSelectedContext;
+            Filter = filter;
+        }
+
+        public CompiledPageActionDescriptor ActionDescriptor { get; }
+        public PageHandlerSelectedContext HandlerSelectedContext { get; }
+        public IAsyncPageFilter Filter { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(HandlerSelectedContext), HandlerSelectedContext),
+            2 => new KeyValuePair<string, object>(nameof(Filter), Filter),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class BeforeOnPageHandlerSelected : EventData
+    {
+        public const string EventName = EventNamespace + nameof(BeforeOnPageHandlerSelected);
+
+        public BeforeOnPageHandlerSelected(CompiledPageActionDescriptor actionDescriptor, PageHandlerSelectedContext handlerSelectedContext, IPageFilter filter)
+        {
+            ActionDescriptor = actionDescriptor;
+            HandlerSelectedContext = handlerSelectedContext;
+            Filter = filter;
+        }
+
+        public CompiledPageActionDescriptor ActionDescriptor { get; }
+        public PageHandlerSelectedContext HandlerSelectedContext { get; }
+        public IPageFilter Filter { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(HandlerSelectedContext), HandlerSelectedContext),
+            2 => new KeyValuePair<string, object>(nameof(Filter), Filter),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class AfterOnPageHandlerSelected : EventData
+    {
+        public const string EventName = EventNamespace + nameof(AfterOnPageHandlerSelected);
+
+        public AfterOnPageHandlerSelected(CompiledPageActionDescriptor actionDescriptor, PageHandlerSelectedContext handlerSelectedContext, IPageFilter filter)
+        {
+            ActionDescriptor = actionDescriptor;
+            HandlerSelectedContext = handlerSelectedContext;
+            Filter = filter;
+        }
+
+        public CompiledPageActionDescriptor ActionDescriptor { get; }
+        public PageHandlerSelectedContext HandlerSelectedContext { get; }
+        public IPageFilter Filter { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(HandlerSelectedContext), HandlerSelectedContext),
+            2 => new KeyValuePair<string, object>(nameof(Filter), Filter),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+}

src/Mvc/Mvc.RazorPages/src/MvcRazorPagesDiagnosticListenerExtensions.cs

@@ -5,16 +5,17 @@ using System.Collections.Generic;
 using System.Diagnostics;
 using Microsoft.AspNetCore.Mvc.Filters;
 using Microsoft.AspNetCore.Mvc.RazorPages.Infrastructure;
+using Microsoft.AspNetCore.Mvc.Diagnostics;
 
 namespace Microsoft.AspNetCore.Mvc.RazorPages
 {
-    internal static class MvcRazorPagesDiagnosticSourceExtensions
+    internal static class MvcRazorPagesDiagnosticListenerExtensions
     {
         public static void BeforeHandlerMethod(
             this DiagnosticListener diagnosticListener,
             ActionContext actionContext,
             HandlerMethodDescriptor handlerMethodDescriptor,
-            IDictionary<string, object> arguments,
+            IReadOnlyDictionary<string, object> arguments,
             object instance)
         {
             Debug.Assert(diagnosticListener != null);
@@ -30,19 +31,18 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages
             }
         }
 
-        private static void BeforeHandlerMethodImpl(DiagnosticListener diagnosticListener, ActionContext actionContext, HandlerMethodDescriptor handlerMethodDescriptor, IDictionary<string, object> arguments, object instance)
+        private static void BeforeHandlerMethodImpl(DiagnosticListener diagnosticListener, ActionContext actionContext, HandlerMethodDescriptor handlerMethodDescriptor, IReadOnlyDictionary<string, object> arguments, object instance)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.BeforeHandlerMethod"))
+            if (diagnosticListener.IsEnabled(Diagnostics.BeforeHandlerMethod.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.BeforeHandlerMethod",
+                    Diagnostics.BeforeHandlerMethod.EventName,
-                    new
+                    new BeforeHandlerMethod(
-                    {
+                        actionContext,
-                        actionContext = actionContext,
+                        arguments,
-                        arguments = arguments,
+                        handlerMethodDescriptor,
-                        handlerMethodDescriptor = handlerMethodDescriptor,
+                        instance
-                        instance = instance,
+                    ));
-                    });
             }
         }
 
@@ -50,7 +50,7 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages
             this DiagnosticListener diagnosticListener,
             ActionContext actionContext,
             HandlerMethodDescriptor handlerMethodDescriptor,
-            IDictionary<string, object> arguments,
+            IReadOnlyDictionary<string, object> arguments,
             object instance,
             IActionResult result)
         {
@@ -67,20 +67,19 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages
             }
         }
 
-        private static void AfterHandlerMethodImpl(DiagnosticListener diagnosticListener, ActionContext actionContext, HandlerMethodDescriptor handlerMethodDescriptor, IDictionary<string, object> arguments, object instance, IActionResult result)
+        private static void AfterHandlerMethodImpl(DiagnosticListener diagnosticListener, ActionContext actionContext, HandlerMethodDescriptor handlerMethodDescriptor, IReadOnlyDictionary<string, object> arguments, object instance, IActionResult result)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.AfterHandlerMethod"))
+            if (diagnosticListener.IsEnabled(Diagnostics.AfterHandlerMethod.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.AfterHandlerMethod",
+                    Diagnostics.AfterHandlerMethod.EventName,
-                    new
+                    new AfterHandlerMethod(
-                    {
+                        actionContext,
-                        actionContext = actionContext,
+                        arguments,
-                        arguments = arguments,
+                        handlerMethodDescriptor,
-                        handlerMethodDescriptor = handlerMethodDescriptor,
+                        instance,
-                        instance = instance,
+                        result
-                        result = result
+                    ));
-                    });
             }
         }
 
@@ -102,16 +101,15 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages
 
         private static void BeforeOnPageHandlerExecutionImpl(DiagnosticListener diagnosticListener, PageHandlerExecutingContext handlerExecutionContext, IAsyncPageFilter filter)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.BeforeOnPageHandlerExecution"))
+            if (diagnosticListener.IsEnabled(Diagnostics.BeforeOnPageHandlerExecution.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.BeforeOnPageHandlerExecution",
+                    Diagnostics.BeforeOnPageHandlerExecution.EventName,
-                    new
+                    new BeforeOnPageHandlerExecution(
-                    {
+                        handlerExecutionContext.ActionDescriptor,
-                        actionDescriptor = handlerExecutionContext.ActionDescriptor,
+                        handlerExecutionContext,
-                        handlerExecutionContext = handlerExecutionContext,
+                        filter
-                        filter = filter
+                    ));
-                    });
             }
         }
 
@@ -133,16 +131,15 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages
 
         private static void AfterOnPageHandlerExecutionImpl(DiagnosticListener diagnosticListener, PageHandlerExecutedContext handlerExecutedContext, IAsyncPageFilter filter)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.AfterOnPageHandlerExecution"))
+            if (diagnosticListener.IsEnabled(Diagnostics.AfterOnPageHandlerExecution.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.AfterOnPageHandlerExecution",
+                    Diagnostics.AfterOnPageHandlerExecution.EventName,
-                    new
+                    new AfterOnPageHandlerExecution(
-                    {
+                        handlerExecutedContext.ActionDescriptor,
-                        actionDescriptor = handlerExecutedContext.ActionDescriptor,
+                        handlerExecutedContext,
-                        handlerExecutedContext = handlerExecutedContext,
+                        filter
-                        filter = filter
+                    ));
-                    });
             }
         }
 
@@ -164,16 +161,15 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages
 
         private static void BeforeOnPageHandlerExecutingImpl(DiagnosticListener diagnosticListener, PageHandlerExecutingContext handlerExecutingContext, IPageFilter filter)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.BeforeOnPageHandlerExecuting"))
+            if (diagnosticListener.IsEnabled(Diagnostics.BeforeOnPageHandlerExecuting.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.BeforeOnPageHandlerExecuting",
+                    Diagnostics.BeforeOnPageHandlerExecuting.EventName,
-                    new
+                    new BeforeOnPageHandlerExecuting(
-                    {
+                        handlerExecutingContext.ActionDescriptor,
-                        actionDescriptor = handlerExecutingContext.ActionDescriptor,
+                        handlerExecutingContext,
-                        handlerExecutingContext = handlerExecutingContext,
+                        filter
-                        filter = filter
+                    ));
-                    });
             }
         }
 
@@ -195,16 +191,15 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages
 
         private static void AfterOnPageHandlerExecutingImpl(DiagnosticListener diagnosticListener, PageHandlerExecutingContext handlerExecutingContext, IPageFilter filter)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.AfterOnPageHandlerExecuting"))
+            if (diagnosticListener.IsEnabled(Diagnostics.AfterOnPageHandlerExecuting.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.AfterOnPageHandlerExecuting",
+                    Diagnostics.AfterOnPageHandlerExecuting.EventName,
-                    new
+                    new AfterOnPageHandlerExecuting(
-                    {
+                        handlerExecutingContext.ActionDescriptor,
-                        actionDescriptor = handlerExecutingContext.ActionDescriptor,
+                        handlerExecutingContext,
-                        handlerExecutingContext = handlerExecutingContext,
+                        filter
-                        filter = filter
+                    ));
-                    });
             }
         }
 
@@ -226,16 +221,15 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages
 
         private static void BeforeOnPageHandlerExecutedImpl(DiagnosticListener diagnosticListener, PageHandlerExecutedContext handlerExecutedContext, IPageFilter filter)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.BeforeOnPageHandlerExecuted"))
+            if (diagnosticListener.IsEnabled(Diagnostics.BeforeOnPageHandlerExecuted.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.BeforeOnPageHandlerExecuted",
+                    Diagnostics.BeforeOnPageHandlerExecuted.EventName,
-                    new
+                    new BeforeOnPageHandlerExecuted(
-                    {
+                        handlerExecutedContext.ActionDescriptor,
-                        actionDescriptor = handlerExecutedContext.ActionDescriptor,
+                        handlerExecutedContext,
-                        handlerExecutedContext = handlerExecutedContext,
+                        filter
-                        filter = filter
+                    ));
-                    });
             }
         }
 
@@ -257,16 +251,15 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages
 
         private static void AfterOnPageHandlerExecutedImpl(DiagnosticListener diagnosticListener, PageHandlerExecutedContext handlerExecutedContext, IPageFilter filter)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.AfterOnPageHandlerExecuted"))
+            if (diagnosticListener.IsEnabled(Diagnostics.AfterOnPageHandlerExecuted.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.AfterOnPageHandlerExecuted",
+                    Diagnostics.AfterOnPageHandlerExecuted.EventName,
-                    new
+                    new AfterOnPageHandlerExecuted(
-                    {
+                        handlerExecutedContext.ActionDescriptor,
-                        actionDescriptor = handlerExecutedContext.ActionDescriptor,
+                        handlerExecutedContext,
-                        handlerExecutedContext = handlerExecutedContext,
+                        filter
-                        filter = filter
+                    ));
-                    });
             }
         }
 
@@ -288,16 +281,15 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages
 
         private static void BeforeOnPageHandlerSelectionImpl(DiagnosticListener diagnosticListener, PageHandlerSelectedContext handlerSelectedContext, IAsyncPageFilter filter)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.BeforeOnPageHandlerSelection"))
+            if (diagnosticListener.IsEnabled(Diagnostics.BeforeOnPageHandlerSelection.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.BeforeOnPageHandlerSelection",
+                    Diagnostics.BeforeOnPageHandlerSelection.EventName,
-                    new
+                    new BeforeOnPageHandlerSelection(
-                    {
+                        handlerSelectedContext.ActionDescriptor,
-                        actionDescriptor = handlerSelectedContext.ActionDescriptor,
+                        handlerSelectedContext,
-                        handlerSelectedContext = handlerSelectedContext,
+                        filter
-                        filter = filter
+                    ));
-                    });
             }
         }
 
@@ -319,16 +311,15 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages
 
         private static void AfterOnPageHandlerSelectionImpl(DiagnosticListener diagnosticListener, PageHandlerSelectedContext handlerSelectedContext, IAsyncPageFilter filter)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.AfterOnPageHandlerSelection"))
+            if (diagnosticListener.IsEnabled(Diagnostics.AfterOnPageHandlerSelection.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.AfterOnPageHandlerSelection",
+                    Diagnostics.AfterOnPageHandlerSelection.EventName,
-                    new
+                    new AfterOnPageHandlerSelection(
-                    {
+                        handlerSelectedContext.ActionDescriptor,
-                        actionDescriptor = handlerSelectedContext.ActionDescriptor,
+                        handlerSelectedContext,
-                        handlerSelectedContext = handlerSelectedContext,
+                        filter
-                        filter = filter
+                    ));
-                    });
             }
         }
 
@@ -350,16 +341,15 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages
 
         private static void BeforeOnPageHandlerSelectedImpl(DiagnosticListener diagnosticListener, PageHandlerSelectedContext handlerSelectedContext, IPageFilter filter)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.BeforeOnPageHandlerSelected"))
+            if (diagnosticListener.IsEnabled(Diagnostics.BeforeOnPageHandlerSelected.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.BeforeOnPageHandlerSelected",
+                    Diagnostics.BeforeOnPageHandlerSelected.EventName,
-                    new
+                    new BeforeOnPageHandlerSelected(
-                    {
+                        handlerSelectedContext.ActionDescriptor,
-                        actionDescriptor = handlerSelectedContext.ActionDescriptor,
+                        handlerSelectedContext,
-                        handlerSelectedContext = handlerSelectedContext,
+                        filter
-                        filter = filter
+                    ));
-                    });
             }
         }
 
@@ -381,16 +371,15 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages
 
         private static void AfterOnPageHandlerSelectedImpl(DiagnosticListener diagnosticListener, PageHandlerSelectedContext handlerSelectedContext, IPageFilter filter)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.AfterOnPageHandlerSelected"))
+            if (diagnosticListener.IsEnabled(Diagnostics.AfterOnPageHandlerSelected.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.AfterOnPageHandlerSelected",
+                    Diagnostics.AfterOnPageHandlerSelected.EventName,
-                    new
+                    new AfterOnPageHandlerSelected(
-                    {
+                        handlerSelectedContext.ActionDescriptor,
-                        actionDescriptor = handlerSelectedContext.ActionDescriptor,
+                        handlerSelectedContext,
-                        handlerSelectedContext = handlerSelectedContext,
+                        filter
-                        filter = filter
+                    ));
-                    });
             }
         }
     }

src/Mvc/Mvc.RazorPages/src/PageBase.cs

@@ -110,38 +110,13 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages
         /// <inheritdoc />
         public override void BeginContext(int position, int length, bool isLiteral)
         {
-            const string BeginContextEvent = "Microsoft.AspNetCore.Mvc.Razor.BeginInstrumentationContext";
+            // noop
-
-            if (DiagnosticSource?.IsEnabled(BeginContextEvent) == true)
-            {
-                DiagnosticSource.Write(
-                    BeginContextEvent,
-                    new
-                    {
-                        httpContext = ViewContext,
-                        path = Path,
-                        position = position,
-                        length = length,
-                        isLiteral = isLiteral,
-                    });
-            }
         }
 
         /// <inheritdoc />
         public override void EndContext()
         {
-            const string EndContextEvent = "Microsoft.AspNetCore.Mvc.Razor.EndInstrumentationContext";
+            // noop
-
-            if (DiagnosticSource?.IsEnabled(EndContextEvent) == true)
-            {
-                DiagnosticSource.Write(
-                    EndContextEvent,
-                    new
-                    {
-                        httpContext = ViewContext,
-                        path = Path,
-                    });
-            }
         }
 
         /// <summary>

src/Mvc/Mvc.ViewFeatures/ref/Microsoft.AspNetCore.Mvc.ViewFeatures.netcoreapp3.0.cs

@@ -213,6 +213,92 @@ namespace Microsoft.AspNetCore.Mvc
         public override System.Threading.Tasks.Task ExecuteResultAsync(Microsoft.AspNetCore.Mvc.ActionContext context) { throw null; }
     }
 }
+namespace Microsoft.AspNetCore.Mvc.Diagnostics
+{
+    public sealed partial class AfterView : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.AfterView";
+        public AfterView(Microsoft.AspNetCore.Mvc.ViewEngines.IView view, Microsoft.AspNetCore.Mvc.Rendering.ViewContext viewContext) { }
+        protected override int Count { get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.ViewEngines.IView View { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Rendering.ViewContext ViewContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+    }
+    public sealed partial class AfterViewComponent : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.AfterViewComponent";
+        public AfterViewComponent(Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor actionDescriptor, Microsoft.AspNetCore.Mvc.ViewComponents.ViewComponentContext viewComponentContext, Microsoft.AspNetCore.Mvc.IViewComponentResult viewComponentResult, object viewComponent) { }
+        public Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+        public object ViewComponent { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.ViewComponents.ViewComponentContext ViewComponentContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.IViewComponentResult ViewComponentResult { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+    }
+    public sealed partial class BeforeView : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.BeforeView";
+        public BeforeView(Microsoft.AspNetCore.Mvc.ViewEngines.IView view, Microsoft.AspNetCore.Mvc.Rendering.ViewContext viewContext) { }
+        protected override int Count { get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.ViewEngines.IView View { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.Rendering.ViewContext ViewContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+    }
+    public sealed partial class BeforeViewComponent : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.BeforeViewComponent";
+        public BeforeViewComponent(Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor actionDescriptor, Microsoft.AspNetCore.Mvc.ViewComponents.ViewComponentContext viewComponentContext, object viewComponent) { }
+        public Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+        public object ViewComponent { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.ViewComponents.ViewComponentContext ViewComponentContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+    }
+    public sealed partial class ViewComponentAfterViewExecute : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.ViewComponentAfterViewExecute";
+        public ViewComponentAfterViewExecute(Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor actionDescriptor, Microsoft.AspNetCore.Mvc.ViewComponents.ViewComponentContext viewComponentContext, Microsoft.AspNetCore.Mvc.ViewEngines.IView view) { }
+        public Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.ViewEngines.IView View { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.ViewComponents.ViewComponentContext ViewComponentContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+    }
+    public sealed partial class ViewComponentBeforeViewExecute : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.ViewComponentBeforeViewExecute";
+        public ViewComponentBeforeViewExecute(Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor actionDescriptor, Microsoft.AspNetCore.Mvc.ViewComponents.ViewComponentContext viewComponentContext, Microsoft.AspNetCore.Mvc.ViewEngines.IView view) { }
+        public Microsoft.AspNetCore.Mvc.Abstractions.ActionDescriptor ActionDescriptor { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.ViewEngines.IView View { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.ViewComponents.ViewComponentContext ViewComponentContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+    }
+    public sealed partial class ViewFound : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.ViewFound";
+        public ViewFound(Microsoft.AspNetCore.Mvc.ActionContext actionContext, bool isMainPage, Microsoft.AspNetCore.Mvc.ActionResult result, string viewName, Microsoft.AspNetCore.Mvc.ViewEngines.IView view) { }
+        public Microsoft.AspNetCore.Mvc.ActionContext ActionContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public bool IsMainPage { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.ActionResult Result { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.ViewEngines.IView View { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public string ViewName { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+    }
+    public sealed partial class ViewNotFound : Microsoft.AspNetCore.Mvc.Diagnostics.EventData
+    {
+        public const string EventName = "Microsoft.AspNetCore.Mvc.ViewNotFound";
+        public ViewNotFound(Microsoft.AspNetCore.Mvc.ActionContext actionContext, bool isMainPage, Microsoft.AspNetCore.Mvc.ActionResult result, string viewName, System.Collections.Generic.IEnumerable<string> searchedLocations) { }
+        public Microsoft.AspNetCore.Mvc.ActionContext ActionContext { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override int Count { get { throw null; } }
+        public bool IsMainPage { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected override System.Collections.Generic.KeyValuePair<string, object> this[int index] { get { throw null; } }
+        public Microsoft.AspNetCore.Mvc.ActionResult Result { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public System.Collections.Generic.IEnumerable<string> SearchedLocations { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        public string ViewName { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+    }
+}
 namespace Microsoft.AspNetCore.Mvc.ModelBinding
 {
     public static partial class ModelStateDictionaryExtensions
@@ -1286,7 +1372,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
         public static readonly string DefaultContentType;
         protected ViewExecutor(Microsoft.AspNetCore.Mvc.Infrastructure.IHttpResponseStreamWriterFactory writerFactory, Microsoft.AspNetCore.Mvc.ViewEngines.ICompositeViewEngine viewEngine, System.Diagnostics.DiagnosticListener diagnosticListener) { }
         public ViewExecutor(Microsoft.Extensions.Options.IOptions<Microsoft.AspNetCore.Mvc.MvcViewOptions> viewOptions, Microsoft.AspNetCore.Mvc.Infrastructure.IHttpResponseStreamWriterFactory writerFactory, Microsoft.AspNetCore.Mvc.ViewEngines.ICompositeViewEngine viewEngine, Microsoft.AspNetCore.Mvc.ViewFeatures.ITempDataDictionaryFactory tempDataFactory, System.Diagnostics.DiagnosticListener diagnosticListener, Microsoft.AspNetCore.Mvc.ModelBinding.IModelMetadataProvider modelMetadataProvider) { }
-        protected System.Diagnostics.DiagnosticListener DiagnosticSource { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
+        protected System.Diagnostics.DiagnosticListener DiagnosticListener { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
         protected Microsoft.AspNetCore.Mvc.ModelBinding.IModelMetadataProvider ModelMetadataProvider { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
         protected Microsoft.AspNetCore.Mvc.ViewFeatures.ITempDataDictionaryFactory TempDataFactory { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }
         protected Microsoft.AspNetCore.Mvc.ViewEngines.IViewEngine ViewEngine { [System.Runtime.CompilerServices.CompilerGeneratedAttribute]get { throw null; } }

src/Mvc/Mvc.ViewFeatures/src/Diagnostics/MvcDiagnostics.cs

@@ -0,0 +1,228 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using Microsoft.AspNetCore.Mvc.Abstractions;
+using Microsoft.AspNetCore.Mvc.Rendering;
+using Microsoft.AspNetCore.Mvc.ViewComponents;
+using Microsoft.AspNetCore.Mvc.ViewEngines;
+
+namespace Microsoft.AspNetCore.Mvc.Diagnostics
+{
+    public sealed class BeforeViewComponent : EventData
+    {
+        public const string EventName = EventNamespace + nameof(BeforeViewComponent);
+
+        public BeforeViewComponent(ActionDescriptor actionDescriptor, ViewComponentContext viewComponentContext, object viewComponent)
+        {
+            ActionDescriptor = actionDescriptor;
+            ViewComponentContext = viewComponentContext;
+            ViewComponent = viewComponent;
+        }
+
+        public ActionDescriptor ActionDescriptor { get; }
+        public ViewComponentContext ViewComponentContext { get; }
+        public object ViewComponent { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(ViewComponentContext), ViewComponentContext),
+            2 => new KeyValuePair<string, object>(nameof(ViewComponent), ViewComponent),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class AfterViewComponent : EventData
+    {
+        public const string EventName = EventNamespace + nameof(AfterViewComponent);
+
+        public AfterViewComponent(ActionDescriptor actionDescriptor, ViewComponentContext viewComponentContext, IViewComponentResult viewComponentResult, object viewComponent)
+        {
+            ActionDescriptor = actionDescriptor;
+            ViewComponentContext = viewComponentContext;
+            ViewComponentResult = viewComponentResult;
+            ViewComponent = viewComponent;
+        }
+
+        public ActionDescriptor ActionDescriptor { get; }
+        public ViewComponentContext ViewComponentContext { get; }
+        public IViewComponentResult ViewComponentResult { get; }
+        public object ViewComponent { get; }
+
+        protected override int Count => 4;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(ViewComponentContext), ViewComponentContext),
+            2 => new KeyValuePair<string, object>(nameof(ViewComponent), ViewComponent),
+            3 => new KeyValuePair<string, object>(nameof(ViewComponentResult), ViewComponentResult),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class ViewComponentBeforeViewExecute : EventData
+    {
+        public const string EventName = EventNamespace + nameof(ViewComponentBeforeViewExecute);
+
+        public ViewComponentBeforeViewExecute(ActionDescriptor actionDescriptor, ViewComponentContext viewComponentContext, IView view)
+        {
+            ActionDescriptor = actionDescriptor;
+            ViewComponentContext = viewComponentContext;
+            View = view;
+        }
+        public ActionDescriptor ActionDescriptor { get; }
+        public ViewComponentContext ViewComponentContext { get; }
+        public IView View { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(ViewComponentContext), ViewComponentContext),
+            2 => new KeyValuePair<string, object>(nameof(View), View),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class ViewComponentAfterViewExecute : EventData
+    {
+        public const string EventName = EventNamespace + nameof(ViewComponentAfterViewExecute);
+
+        public ViewComponentAfterViewExecute(ActionDescriptor actionDescriptor, ViewComponentContext viewComponentContext, IView view)
+        {
+            ActionDescriptor = actionDescriptor;
+            ViewComponentContext = viewComponentContext;
+            View = view;
+        }
+
+        public ActionDescriptor ActionDescriptor { get; }
+        public ViewComponentContext ViewComponentContext { get; }
+        public IView View { get; }
+
+        protected override int Count => 3;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionDescriptor), ActionDescriptor),
+            1 => new KeyValuePair<string, object>(nameof(ViewComponentContext), ViewComponentContext),
+            2 => new KeyValuePair<string, object>(nameof(View), View),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class BeforeView : EventData
+    {
+        public const string EventName = EventNamespace + nameof(BeforeView);
+
+        public BeforeView(IView view, ViewContext viewContext)
+        {
+            View = view;
+            ViewContext = viewContext;
+        }
+
+        public IView View { get; }
+        public ViewContext ViewContext { get; }
+
+        protected override int Count => 2;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(View), View),
+            1 => new KeyValuePair<string, object>(nameof(ViewContext), ViewContext),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class AfterView : EventData
+    {
+        public const string EventName = EventNamespace + nameof(AfterView);
+
+        public AfterView(IView view, ViewContext viewContext)
+        {
+            View = view;
+            ViewContext = viewContext;
+        }
+
+        public IView View { get; }
+        public ViewContext ViewContext { get; }
+
+        protected override int Count => 2;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(View), View),
+            1 => new KeyValuePair<string, object>(nameof(ViewContext), ViewContext),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class ViewFound : EventData
+    {
+        public const string EventName = EventNamespace + nameof(ViewFound);
+
+        public ViewFound(ActionContext actionContext, bool isMainPage, ActionResult result, string viewName, IView view)
+        {
+            ActionContext = actionContext;
+            IsMainPage = isMainPage;
+            Result = result;
+            ViewName = viewName;
+            View = view;
+        }
+
+        public ActionContext ActionContext { get; }
+        public bool IsMainPage { get; }
+        public ActionResult Result { get; }
+        public string ViewName { get; }
+        public IView View { get; }
+
+        protected override int Count => 5;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionContext), ActionContext),
+            1 => new KeyValuePair<string, object>(nameof(IsMainPage), IsMainPage),
+            2 => new KeyValuePair<string, object>(nameof(Result), Result),
+            3 => new KeyValuePair<string, object>(nameof(ViewName), ViewName),
+            4 => new KeyValuePair<string, object>(nameof(View), View),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+
+    public sealed class ViewNotFound : EventData
+    {
+        public const string EventName = EventNamespace + nameof(ViewNotFound);
+
+        public ViewNotFound(ActionContext actionContext, bool isMainPage, ActionResult result, string viewName, IEnumerable<string> searchedLocations)
+        {
+            ActionContext = actionContext;
+            IsMainPage = isMainPage;
+            Result = result;
+            ViewName = viewName;
+            SearchedLocations = searchedLocations;
+        }
+
+        public ActionContext ActionContext { get; }
+        public bool IsMainPage { get; }
+        public ActionResult Result { get; }
+        public string ViewName { get; }
+        public IEnumerable<string> SearchedLocations { get; }
+
+        protected override int Count => 5;
+
+        protected override KeyValuePair<string, object> this[int index] => index switch
+        {
+            0 => new KeyValuePair<string, object>(nameof(ActionContext), ActionContext),
+            1 => new KeyValuePair<string, object>(nameof(IsMainPage), IsMainPage),
+            2 => new KeyValuePair<string, object>(nameof(Result), Result),
+            3 => new KeyValuePair<string, object>(nameof(ViewName), ViewName),
+            4 => new KeyValuePair<string, object>(nameof(SearchedLocations), SearchedLocations),
+            _ => throw new IndexOutOfRangeException(nameof(index))
+        };
+    }
+}

src/Mvc/Mvc.ViewFeatures/src/MvcViewFeaturesDiagnosticListenerExtensions.cs

@@ -6,10 +6,11 @@ using System.Diagnostics;
 using Microsoft.AspNetCore.Mvc.Rendering;
 using Microsoft.AspNetCore.Mvc.ViewComponents;
 using Microsoft.AspNetCore.Mvc.ViewEngines;
+using Microsoft.AspNetCore.Mvc.Diagnostics;
 
 namespace Microsoft.AspNetCore.Mvc.ViewFeatures
 {
-    internal static class MvcViewFeaturesDiagnosticSourceExtensions
+    internal static class MvcViewFeaturesDiagnosticListenerExtensions
     {
         public static void BeforeViewComponent(
             this DiagnosticListener diagnosticListener,
@@ -25,16 +26,15 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
 
         private static void BeforeViewComponentImpl(DiagnosticListener diagnosticListener, ViewComponentContext context, object viewComponent)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.BeforeViewComponent"))
+            if (diagnosticListener.IsEnabled(Diagnostics.BeforeViewComponent.EventName))
             {
                 diagnosticListener.Write(
-                "Microsoft.AspNetCore.Mvc.BeforeViewComponent",
+                Diagnostics.BeforeViewComponent.EventName,
-                new
+                new BeforeViewComponent(
-                {
+                    context.ViewContext.ActionDescriptor,
-                    actionDescriptor = context.ViewContext.ActionDescriptor,
+                    context,
-                    viewComponentContext = context,
+                    viewComponent
-                    viewComponent = viewComponent
+                ));
-                });
             }
         }
 
@@ -53,17 +53,16 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
 
         private static void AfterViewComponentImpl(DiagnosticListener diagnosticListener, ViewComponentContext context, IViewComponentResult result, object viewComponent)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.AfterViewComponent"))
+            if (diagnosticListener.IsEnabled(Diagnostics.AfterViewComponent.EventName))
             {
                 diagnosticListener.Write(
-                "Microsoft.AspNetCore.Mvc.AfterViewComponent",
+                Diagnostics.AfterViewComponent.EventName,
-                new
+                new AfterViewComponent(
-                {
+                    context.ViewContext.ActionDescriptor,
-                    actionDescriptor = context.ViewContext.ActionDescriptor,
+                    context,
-                    viewComponentContext = context,
+                    result,
-                    viewComponentResult = result,
+                    viewComponent
-                    viewComponent = viewComponent
+                ));
-                });
             }
         }
 
@@ -81,16 +80,15 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
 
         private static void ViewComponentBeforeViewExecuteImpl(DiagnosticListener diagnosticListener, ViewComponentContext context, IView view)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.ViewComponentBeforeViewExecute"))
+            if (diagnosticListener.IsEnabled(Diagnostics.ViewComponentBeforeViewExecute.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.ViewComponentBeforeViewExecute",
+                    Diagnostics.ViewComponentBeforeViewExecute.EventName,
-                    new
+                    new ViewComponentBeforeViewExecute(
-                    {
+                        context.ViewContext.ActionDescriptor,
-                        actionDescriptor = context.ViewContext.ActionDescriptor,
+                        context,
-                        viewComponentContext = context,
+                        view
-                        view = view
+                    ));
-                    });
             }
         }
 
@@ -108,16 +106,15 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
 
         private static void ViewComponentAfterViewExecuteImpl(DiagnosticListener diagnosticListener, ViewComponentContext context, IView view)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.ViewComponentAfterViewExecute"))
+            if (diagnosticListener.IsEnabled(Diagnostics.ViewComponentAfterViewExecute.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.ViewComponentAfterViewExecute",
+                    Diagnostics.ViewComponentAfterViewExecute.EventName,
-                    new
+                    new ViewComponentAfterViewExecute(
-                    {
+                        context.ViewContext.ActionDescriptor,
-                        actionDescriptor = context.ViewContext.ActionDescriptor,
+                        context,
-                        viewComponentContext = context,
+                        view
-                        view = view
+                    ));
-                    });
             }
         }
 
@@ -135,11 +132,11 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
 
         private static void BeforeViewImpl(DiagnosticListener diagnosticListener, IView view, ViewContext viewContext)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.BeforeView"))
+            if (diagnosticListener.IsEnabled(Diagnostics.BeforeView.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.BeforeView",
+                    Diagnostics.BeforeView.EventName,
-                    new { view = view, viewContext = viewContext, });
+                    new BeforeView(view, viewContext));
             }
         }
 
@@ -157,11 +154,11 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
 
         private static void AfterViewImpl(DiagnosticListener diagnosticListener, IView view, ViewContext viewContext)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.AfterView"))
+            if (diagnosticListener.IsEnabled(Diagnostics.AfterView.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.AfterView",
+                    Diagnostics.AfterView.EventName,
-                    new { view = view, viewContext = viewContext, });
+                    new AfterView(view, viewContext));
             }
         }
 
@@ -169,7 +166,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
             this DiagnosticListener diagnosticListener,
             ActionContext actionContext,
             bool isMainPage,
-            PartialViewResult viewResult,
+            ActionResult viewResult,
             string viewName,
             IView view)
         {
@@ -180,20 +177,19 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
             }
         }
 
-        private static void ViewFoundImpl(DiagnosticListener diagnosticListener, ActionContext actionContext, bool isMainPage, PartialViewResult viewResult, string viewName, IView view)
+        private static void ViewFoundImpl(DiagnosticListener diagnosticListener, ActionContext actionContext, bool isMainPage, ActionResult viewResult, string viewName, IView view)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.ViewFound"))
+            if (diagnosticListener.IsEnabled(Diagnostics.ViewFound.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.ViewFound",
+                    Diagnostics.ViewFound.EventName,
-                    new
+                    new ViewFound(
-                    {
+                        actionContext,
-                        actionContext = actionContext,
+                        isMainPage,
-                        isMainPage = isMainPage,
+                        viewResult,
-                        result = viewResult,
+                        viewName,
-                        viewName = viewName,
+                        view
-                        view = view,
+                    ));
-                    });
             }
         }
 
@@ -201,7 +197,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
             this DiagnosticListener diagnosticListener,
             ActionContext actionContext,
             bool isMainPage,
-            PartialViewResult viewResult,
+            ActionResult viewResult,
             string viewName,
             IEnumerable<string> searchedLocations)
         {
@@ -212,20 +208,19 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
             }
         }
 
-        private static void ViewNotFoundImpl(DiagnosticListener diagnosticListener, ActionContext actionContext, bool isMainPage, PartialViewResult viewResult, string viewName, IEnumerable<string> searchedLocations)
+        private static void ViewNotFoundImpl(DiagnosticListener diagnosticListener, ActionContext actionContext, bool isMainPage, ActionResult viewResult, string viewName, IEnumerable<string> searchedLocations)
         {
-            if (diagnosticListener.IsEnabled("Microsoft.AspNetCore.Mvc.ViewNotFound"))
+            if (diagnosticListener.IsEnabled(Diagnostics.ViewNotFound.EventName))
             {
                 diagnosticListener.Write(
-                    "Microsoft.AspNetCore.Mvc.ViewNotFound",
+                    Diagnostics.ViewNotFound.EventName,
-                    new
+                    new ViewNotFound(
-                    {
+                        actionContext,
-                        actionContext = actionContext,
+                        isMainPage,
-                        isMainPage = isMainPage,
+                        viewResult,
-                        result = viewResult,
+                        viewName,
-                        viewName = viewName,
+                        searchedLocations
-                        searchedLocations = searchedLocations,
+                    ));
-                    });
             }
         }
     }

src/Mvc/Mvc.ViewFeatures/src/PartialViewResultExecutor.cs

@@ -108,7 +108,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
 
             if (result.Success)
             {
-                DiagnosticSource.ViewFound(
+                DiagnosticListener.ViewFound(
                     actionContext,
                     isMainPage: false,
                     viewResult: viewResult,
@@ -119,7 +119,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
             }
             else
             {
-                DiagnosticSource.ViewNotFound(
+                DiagnosticListener.ViewNotFound(
                     actionContext,
                     isMainPage: false,
                     viewResult: viewResult,

src/Mvc/Mvc.ViewFeatures/src/ViewExecutor.cs

@@ -32,7 +32,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
         /// <param name="writerFactory">The <see cref="IHttpResponseStreamWriterFactory"/>.</param>
         /// <param name="viewEngine">The <see cref="ICompositeViewEngine"/>.</param>
         /// <param name="tempDataFactory">The <see cref="ITempDataDictionaryFactory"/>.</param>
-        /// <param name="diagnosticListener">The <see cref="DiagnosticSource"/>.</param>
+        /// <param name="diagnosticListener">The <see cref="DiagnosticListener"/>.</param>
         /// <param name="modelMetadataProvider">The <see cref="IModelMetadataProvider" />.</param>
         public ViewExecutor(
             IOptions<MvcViewOptions> viewOptions,
@@ -91,13 +91,13 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
 
             WriterFactory = writerFactory;
             ViewEngine = viewEngine;
-            DiagnosticSource = diagnosticListener;
+            DiagnosticListener = diagnosticListener;
         }
 
         /// <summary>
-        /// Gets the <see cref="DiagnosticSource"/>.
+        /// Gets the <see cref="DiagnosticListener"/>.
         /// </summary>
-        protected DiagnosticListener DiagnosticSource { get; }
+        protected DiagnosticListener DiagnosticListener { get; }
 
         /// <summary>
         /// Gets the <see cref="ITempDataDictionaryFactory"/>.
@@ -242,11 +242,11 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
                 {
                     viewContext.Writer = writer;
 
-                    DiagnosticSource.BeforeView(view, viewContext);
+                    DiagnosticListener.BeforeView(view, viewContext);
 
                     await view.RenderAsync(viewContext);
 
-                    DiagnosticSource.AfterView(view, viewContext);
+                    DiagnosticListener.AfterView(view, viewContext);
                 }
                 finally
                 {

src/Mvc/Mvc.ViewFeatures/src/ViewResultExecutor.cs

@@ -107,7 +107,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
                 }
             }
 
-            if (DiagnosticSource.IsEnabled())
+            if (DiagnosticListener.IsEnabled())
             {
                 OutputDiagnostics(actionContext, viewResult, viewName, stopwatch, result);
             }
@@ -128,35 +128,21 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
         {
             if (result.Success)
             {
-                if (DiagnosticSource.IsEnabled("Microsoft.AspNetCore.Mvc.ViewFound"))
+                DiagnosticListener.ViewFound(
-                {
+                    actionContext,
-                    DiagnosticSource.Write(
+                    isMainPage: true,
-                        "Microsoft.AspNetCore.Mvc.ViewFound",
+                    viewResult,
-                        new
+                    viewName,
-                        {
+                    view: result.View);
-                            actionContext,
-                            isMainPage = true,
-                            result = viewResult,
-                            viewName,
-                            view = result.View,
-                        });
-                }
             }
             else
             {
-                if (DiagnosticSource.IsEnabled("Microsoft.AspNetCore.Mvc.ViewNotFound"))
+                DiagnosticListener.ViewNotFound(
-                {
+                    actionContext,
-                    DiagnosticSource.Write(
+                    isMainPage: true,
-                        "Microsoft.AspNetCore.Mvc.ViewNotFound",
+                    viewResult,
-                        new
+                    viewName,
-                        {
+                    searchedLocations: result.SearchedLocations);
-                            actionContext,
-                            isMainPage = true,
-                            result = viewResult,
-                            viewName,
-                            searchedLocations = result.SearchedLocations
-                        });
-                }
             }
         }
 

src/Mvc/Mvc.ViewFeatures/test/ViewComponentResultTest.cs

@@ -264,7 +264,7 @@ namespace Microsoft.AspNetCore.Mvc
         }
 
         [Fact]
-        public async Task ExecuteResultAsync_ExecutesViewComponent_AndWritesDiagnosticSource()
+        public async Task ExecuteResultAsync_ExecutesViewComponent_AndWritesDiagnosticListener()
         {
             // Arrange
             var methodInfo = typeof(TextViewComponent).GetMethod(nameof(TextViewComponent.Invoke));

src/Mvc/Mvc.ViewFeatures/test/ViewComponents/ViewViewComponentResultTest.cs

@@ -102,7 +102,7 @@ namespace Microsoft.AspNetCore.Mvc
         }
 
         [Fact]
-        public void Execute_ResolvesView_AndWritesDiagnosticSource()
+        public void Execute_ResolvesView_AndWritesDiagnosticListener()
         {
             // Arrange
             var view = new Mock<IView>(MockBehavior.Strict);