[wip] Update Razor SDK and resolve issues

I'm still chasing one more issue.

eng/Version.Details.xml

@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <!--
 
   This file is used by automation to update Versions.props and may be used for other purposes, such as
@@ -9,21 +9,21 @@
 -->
 <Dependencies>
   <ProductDependencies>
-    <Dependency Name="Microsoft.AspNetCore.Razor.Language" Version="3.0.0-preview-19107-04">
+    <Dependency Name="Microsoft.AspNetCore.Razor.Language" Version="3.0.0-preview3.19119.5">
       <Uri>https://github.com/aspnet/AspNetCore-Tooling</Uri>
-      <Sha>408b123a6454841884c1d840fb853eec8de12c10</Sha>
+      <Sha>182b2c81a5a3c2d5219cf20205e49dbe86823e18</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.AspNetCore.Mvc.Razor.Extensions" Version="3.0.0-preview-19107-04">
+    <Dependency Name="Microsoft.AspNetCore.Mvc.Razor.Extensions" Version="3.0.0-preview3.19119.5">
       <Uri>https://github.com/aspnet/AspNetCore-Tooling</Uri>
-      <Sha>408b123a6454841884c1d840fb853eec8de12c10</Sha>
+      <Sha>182b2c81a5a3c2d5219cf20205e49dbe86823e18</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.CodeAnalysis.Razor" Version="3.0.0-preview-19107-04">
+    <Dependency Name="Microsoft.CodeAnalysis.Razor" Version="3.0.0-preview3.19119.5">
       <Uri>https://github.com/aspnet/AspNetCore-Tooling</Uri>
-      <Sha>408b123a6454841884c1d840fb853eec8de12c10</Sha>
+      <Sha>182b2c81a5a3c2d5219cf20205e49dbe86823e18</Sha>
     </Dependency>
-    <Dependency Name="Microsoft.NET.Sdk.Razor" Version="3.0.0-preview-19107-04">
+    <Dependency Name="Microsoft.NET.Sdk.Razor" Version="3.0.0-preview3.19119.5">
       <Uri>https://github.com/aspnet/AspNetCore-Tooling</Uri>
-      <Sha>408b123a6454841884c1d840fb853eec8de12c10</Sha>
+      <Sha>182b2c81a5a3c2d5219cf20205e49dbe86823e18</Sha>
     </Dependency>
     <Dependency Name="dotnet-ef" Version="3.0.0-preview.19080.1">
       <Uri>https://github.com/aspnet/EntityFrameworkCore</Uri>

eng/Versions.props

@@ -1,4 +1,4 @@
-
+
 <!--
 
   This file defines the versions of external dependencies used by ASP.NET Core.
@@ -112,10 +112,10 @@
     <MicrosoftEntityFrameworkCoreToolsPackageVersion>3.0.0-preview.19080.1</MicrosoftEntityFrameworkCoreToolsPackageVersion>
     <MicrosoftEntityFrameworkCorePackageVersion>3.0.0-preview.19080.1</MicrosoftEntityFrameworkCorePackageVersion>
     <!-- Packages from aspnet/AspNetCore-Tooling -->
-    <MicrosoftAspNetCoreMvcRazorExtensionsPackageVersion>3.0.0-preview-19107-04</MicrosoftAspNetCoreMvcRazorExtensionsPackageVersion>
+    <MicrosoftAspNetCoreMvcRazorExtensionsPackageVersion>3.0.0-preview3.19119.5</MicrosoftAspNetCoreMvcRazorExtensionsPackageVersion>
-    <MicrosoftAspNetCoreRazorLanguagePackageVersion>3.0.0-preview-19107-04</MicrosoftAspNetCoreRazorLanguagePackageVersion>
+    <MicrosoftAspNetCoreRazorLanguagePackageVersion>3.0.0-preview3.19119.5</MicrosoftAspNetCoreRazorLanguagePackageVersion>
-    <MicrosoftCodeAnalysisRazorPackageVersion>3.0.0-preview-19107-04</MicrosoftCodeAnalysisRazorPackageVersion>
+    <MicrosoftCodeAnalysisRazorPackageVersion>3.0.0-preview3.19119.5</MicrosoftCodeAnalysisRazorPackageVersion>
-    <MicrosoftNETSdkRazorPackageVersion>3.0.0-preview-19107-04</MicrosoftNETSdkRazorPackageVersion>
+    <MicrosoftNETSdkRazorPackageVersion>3.0.0-preview3.19119.5</MicrosoftNETSdkRazorPackageVersion>
   </PropertyGroup>
   <!--
 

src/Components/Blazor/Build/test/BindRazorIntegrationTest.cs

@@ -91,7 +91,7 @@ namespace Test
                 frames,
                 frame => AssertFrame.Component(frame, "Test.MyComponent", 3, 0),
                 frame => AssertFrame.Attribute(frame, "Value", 42, 1),
-                frame => AssertFrame.Attribute(frame, "ValueChanged", typeof(Action<UIEventArgs>), 2));
+                frame => AssertFrame.Attribute(frame, "ValueChanged", typeof(EventCallback<UIChangeEventArgs>), 2));
         }
 
         [Fact]
@@ -167,7 +167,7 @@ namespace Test
                 frames,
                 frame => AssertFrame.Component(frame, "Test.MyComponent", 3, 0),
                 frame => AssertFrame.Attribute(frame, "Value", 42, 1),
-                frame => AssertFrame.Attribute(frame, "OnChanged", typeof(Action<UIEventArgs>), 2));
+                frame => AssertFrame.Attribute(frame, "OnChanged", typeof(EventCallback<UIChangeEventArgs>), 2));
         }
 
         [Fact]
@@ -201,7 +201,7 @@ namespace Test
                 frames,
                 frame => AssertFrame.Element(frame, "div", 3, 0),
                 frame => AssertFrame.Attribute(frame, "myvalue", "hi", 1),
-                frame => AssertFrame.Attribute(frame, "myevent", typeof(Action<UIEventArgs>), 2));
+                frame => AssertFrame.Attribute(frame, "myevent", typeof(EventCallback), 2));
         }
 
         [Fact]
@@ -235,7 +235,7 @@ namespace Test
                 frames,
                 frame => AssertFrame.Element(frame, "div", 3, 0),
                 frame => AssertFrame.Attribute(frame, "myvalue", "hi", 1),
-                frame => AssertFrame.Attribute(frame, "myevent", typeof(Action<UIEventArgs>), 2));
+                frame => AssertFrame.Attribute(frame, "myevent", typeof(EventCallback), 2));
         }
 
         [Fact]
@@ -292,7 +292,7 @@ namespace Test
                 frames,
                 frame => AssertFrame.Element(frame, "input", 3, 0),
                 frame => AssertFrame.Attribute(frame, "value", "42", 1),
-                frame => AssertFrame.Attribute(frame, "onchange", typeof(Action<UIEventArgs>), 2));
+                frame => AssertFrame.Attribute(frame, "onchange", typeof(EventCallback), 2));
         }
 
         [Fact]
@@ -315,7 +315,7 @@ namespace Test
                 frame => AssertFrame.Element(frame, "input", 4, 0),
                 frame => AssertFrame.Attribute(frame, "type", "text", 1),
                 frame => AssertFrame.Attribute(frame, "value", new DateTime(2018, 1, 1).ToString("MM/dd/yyyy"), 2),
-                frame => AssertFrame.Attribute(frame, "onchange", typeof(Action<UIEventArgs>), 3));
+                frame => AssertFrame.Attribute(frame, "onchange", typeof(EventCallback), 3));
         }
 
         [Fact]
@@ -340,7 +340,7 @@ namespace Test
                 frame => AssertFrame.Element(frame, "input", 4, 0),
                 frame => AssertFrame.Attribute(frame, "type", "text", 1),
                 frame => AssertFrame.Attribute(frame, "value", new DateTime(2018, 1, 1).ToString("MM/dd/yyyy"), 2),
-                frame => AssertFrame.Attribute(frame, "onchange", typeof(Action<UIEventArgs>), 3));
+                frame => AssertFrame.Attribute(frame, "onchange", typeof(EventCallback), 3));
         }
 
         [Fact]
@@ -363,7 +363,7 @@ namespace Test
                 frame => AssertFrame.Element(frame, "input", 4, 0),
                 frame => AssertFrame.Attribute(frame, "type", "text", 1),
                 frame => AssertFrame.Attribute(frame, "value", "42", 2),
-                frame => AssertFrame.Attribute(frame, "onchange", typeof(Action<UIEventArgs>), 3));
+                frame => AssertFrame.Attribute(frame, "onchange", typeof(EventCallback), 3));
         }
 
         [Fact]
@@ -385,7 +385,7 @@ namespace Test
                 frames,
                 frame => AssertFrame.Element(frame, "input", 3, 0),
                 frame => AssertFrame.Attribute(frame, "type", "checkbox", 1),
-                frame => AssertFrame.Attribute(frame, "onchange", typeof(Action<UIEventArgs>), 3));
+                frame => AssertFrame.Attribute(frame, "onchange", typeof(EventCallback), 3));
         }
 
         [Fact]
@@ -408,7 +408,7 @@ namespace Test
                 frame => AssertFrame.Element(frame, "input", 4, 0),
                 frame => AssertFrame.Attribute(frame, "type", "text", 1),
                 frame => AssertFrame.Attribute(frame, "value", "42", 2),
-                frame => AssertFrame.Attribute(frame, "onchange", typeof(Action<UIEventArgs>), 3));
+                frame => AssertFrame.Attribute(frame, "onchange", typeof(EventCallback), 3));
         }
 
         [Fact]
@@ -431,7 +431,7 @@ namespace Test
                 frame => AssertFrame.Element(frame, "input", 4, 0),
                 frame => AssertFrame.Attribute(frame, "type", "text", 1),
                 frame => AssertFrame.Attribute(frame, "value", new DateTime(2018, 1, 1).ToString("MM/dd"), 2),
-                frame => AssertFrame.Attribute(frame, "onchange", typeof(Action<UIEventArgs>), 3));
+                frame => AssertFrame.Attribute(frame, "onchange", typeof(EventCallback), 3));
         }
 
         [Fact] // Additional coverage of OrphanTagHelperLoweringPass
@@ -455,7 +455,7 @@ namespace Test
                 frame => AssertFrame.Attribute(frame, "type", "text", 1),
                 frame => AssertFrame.Attribute(frame, "visible", 2),
                 frame => AssertFrame.Attribute(frame, "value", "42", 3),
-                frame => AssertFrame.Attribute(frame, "onchange", typeof(Action<UIEventArgs>), 4));
+                frame => AssertFrame.Attribute(frame, "onchange", typeof(EventCallback), 4));
         }
 
         [Fact] // See https://github.com/aspnet/Blazor/issues/703
@@ -482,7 +482,7 @@ namespace Test
                 frame => AssertFrame.Attribute(frame, "type", "text", 1),
                 frame => AssertFrame.Attribute(frame, "visible", 2),
                 frame => AssertFrame.Attribute(frame, "value", "42", 3),
-                frame => AssertFrame.Attribute(frame, "onchange", typeof(Action<UIEventArgs>), 4));
+                frame => AssertFrame.Attribute(frame, "onchange", typeof(EventCallback), 4));
         }
 
         [Fact] // Additional coverage of OrphanTagHelperLoweringPass
@@ -506,7 +506,7 @@ namespace Test
                 frames,
                 frame => AssertFrame.Element(frame, "div", 7, 0),
                 frame => AssertFrame.Attribute(frame, "value", "42", 1),
-                frame => AssertFrame.Attribute(frame, "onchange", typeof(Action<UIEventArgs>), 2),
+                frame => AssertFrame.Attribute(frame, "onchange", typeof(EventCallback), 2),
                 frame => AssertFrame.Whitespace(frame, 3),
                 frame => AssertFrame.Element(frame, "span", 2, 4),
                 frame => AssertFrame.Text(frame, "42", 5),

src/Components/Blazor/Build/test/RenderingRazorIntegrationTest.cs

@@ -365,7 +365,7 @@ namespace Microsoft.AspNetCore.Blazor.Build.Test
             var renderer = new TestRenderer();
 
             // Assert
-            Action<UIEventArgs> setter = null;
+            EventCallback setter = default;
             var frames = GetRenderTree(renderer, component);
             Assert.Collection(frames,
                 frame => AssertFrame.Element(frame, "input", 3, 0),
@@ -373,11 +373,16 @@ namespace Microsoft.AspNetCore.Blazor.Build.Test
                 frame =>
                 {
                     AssertFrame.Attribute(frame, "onchange", 2);
-                    setter = Assert.IsType<Action<UIEventArgs>>(frame.AttributeValue);
+                    setter = Assert.IsType<EventCallback>(frame.AttributeValue);
                 });
 
             // Trigger the change event to show it updates the property
-            await renderer.Invoke(() => setter(new UIChangeEventArgs { Value = "Modified value", }));
+            //
+            // This should always complete synchronously.
+            var task = renderer.InvokeAsync(() => setter.InvokeAsync(new UIChangeEventArgs { Value = "Modified value", }));
+            Assert.Equal(TaskStatus.RanToCompletion, task.Status);
+            await task;
+
             Assert.Equal("Modified value", myValueProperty.GetValue(component));
         }
 
@@ -395,7 +400,7 @@ namespace Microsoft.AspNetCore.Blazor.Build.Test
             var renderer = new TestRenderer();
 
             // Assert
-            Action<UIEventArgs> setter = null;
+            EventCallback setter = default;
             var frames = GetRenderTree(renderer, component);
             Assert.Collection(frames,
                 frame => AssertFrame.Element(frame, "textarea", 3, 0),
@@ -403,11 +408,16 @@ namespace Microsoft.AspNetCore.Blazor.Build.Test
                 frame =>
                 {
                     AssertFrame.Attribute(frame, "onchange", 2);
-                    setter = Assert.IsType<Action<UIEventArgs>>(frame.AttributeValue);
+                    setter = Assert.IsType<EventCallback>(frame.AttributeValue);
                 });
 
             // Trigger the change event to show it updates the property
-            await renderer.Invoke(() => setter(new UIChangeEventArgs() { Value = "Modified value", }));
+            //
+            // This should always complete synchronously.
+            var task = renderer.InvokeAsync(() => setter.InvokeAsync(new UIChangeEventArgs { Value = "Modified value", }));
+            Assert.Equal(TaskStatus.RanToCompletion, task.Status);
+            await task;
+
             Assert.Equal("Modified value", myValueProperty.GetValue(component));
         }
 
@@ -425,7 +435,7 @@ namespace Microsoft.AspNetCore.Blazor.Build.Test
             var renderer = new TestRenderer();
 
             // Assert
-            Action<UIEventArgs> setter = null;
+            EventCallback setter = default;
             var frames = GetRenderTree(renderer, component);
             Assert.Collection(frames,
                 frame => AssertFrame.Element(frame, "input", 3, 0),
@@ -433,12 +443,18 @@ namespace Microsoft.AspNetCore.Blazor.Build.Test
                 frame =>
                 {
                     AssertFrame.Attribute(frame, "onchange", 2);
-                    setter = Assert.IsType<Action<UIEventArgs>>(frame.AttributeValue);
+                    setter = Assert.IsType<EventCallback>(frame.AttributeValue);
                 });
 
             // Trigger the change event to show it updates the property
+            // Trigger the change event to show it updates the property
+            //
+            // This should always complete synchronously.
             var newDateValue = new DateTime(2018, 3, 5, 4, 5, 6);
-            await renderer.Invoke(() => setter(new UIChangeEventArgs() { Value = newDateValue.ToString(), }));
+            var task = renderer.InvokeAsync(() => setter.InvokeAsync(new UIChangeEventArgs { Value = newDateValue.ToString(), }));
+            Assert.Equal(TaskStatus.RanToCompletion, task.Status);
+            await task;
+
             Assert.Equal(newDateValue, myDateProperty.GetValue(component));
         }
 
@@ -457,7 +473,7 @@ namespace Microsoft.AspNetCore.Blazor.Build.Test
             var renderer = new TestRenderer();
 
             // Assert
-            Action<UIEventArgs> setter = null;
+            EventCallback setter = default;
             var frames = GetRenderTree(renderer, component);
             Assert.Collection(frames,
                 frame => AssertFrame.Element(frame, "input", 3, 0),
@@ -465,11 +481,16 @@ namespace Microsoft.AspNetCore.Blazor.Build.Test
                 frame =>
                 {
                     AssertFrame.Attribute(frame, "onchange", 2);
-                    setter = Assert.IsType<Action<UIEventArgs>>(frame.AttributeValue);
+                    setter = Assert.IsType<EventCallback>(frame.AttributeValue);
                 });
 
             // Trigger the change event to show it updates the property
-            await renderer.Invoke(() => setter(new UIChangeEventArgs() { Value = new DateTime(2018, 3, 5).ToString(testDateFormat), }));
+            //
+            // This should always complete synchronously.
+            var task = renderer.InvokeAsync(() => setter.InvokeAsync(new UIChangeEventArgs { Value = new DateTime(2018, 3, 5).ToString(testDateFormat), }));
+            Assert.Equal(TaskStatus.RanToCompletion, task.Status);
+            await task;
+
             Assert.Equal(new DateTime(2018, 3, 5), myDateProperty.GetValue(component));
         }
 
@@ -540,18 +561,22 @@ namespace Microsoft.AspNetCore.Blazor.Build.Test
             var frames = GetRenderTree(renderer, component);
 
             // Assert
-            Assert.Collection(frames,
+            Action<UIMouseEventArgs> func = default; // Since this is a method group, we don't need to create an EventCallback
+            Assert.Collection(
+                frames,
                 frame => AssertFrame.Element(frame, "button", 2, 0),
                 frame =>
                 {
                     AssertFrame.Attribute(frame, "onclick", 1);
 
-                    var func = Assert.IsType<Action<UIMouseEventArgs>>(frame.AttributeValue);
+                    func = Assert.IsType<Action<UIMouseEventArgs>>(frame.AttributeValue);
                     Assert.False((bool)clicked.GetValue(component));
 
-                    func(new UIMouseEventArgs());
+
-                    Assert.True((bool)clicked.GetValue(component));
                 });
+
+            func.Invoke(new UIMouseEventArgs());
+            Assert.True((bool)clicked.GetValue(component));
         }
 
         [Fact]
@@ -568,7 +593,7 @@ namespace Microsoft.AspNetCore.Blazor.Build.Test
             var renderer = new TestRenderer();
 
             // Assert
-            Action<UIEventArgs> setter = null;
+            EventCallback setter = default;
             var frames = GetRenderTree(renderer, component);
             Assert.Collection(frames,
                 frame => AssertFrame.Element(frame, "input", 3, 0),
@@ -576,11 +601,16 @@ namespace Microsoft.AspNetCore.Blazor.Build.Test
                 frame =>
                 {
                     AssertFrame.Attribute(frame, "onchange", 2);
-                    setter = Assert.IsType<Action<UIEventArgs>>(frame.AttributeValue);
+                    setter = Assert.IsType<EventCallback>(frame.AttributeValue);
                 });
 
             // Trigger the change event to show it updates the property
-            await renderer.Invoke(() => setter(new UIChangeEventArgs() { Value = false, }));
+            //
+            // This should always complete synchronously.
+            var task =  renderer.InvokeAsync(() => setter.InvokeAsync(new UIChangeEventArgs() { Value = false, }));
+            Assert.Equal(TaskStatus.RanToCompletion, task.Status);
+            await task;
+
             Assert.False((bool)myValueProperty.GetValue(component));
         }
 
@@ -599,7 +629,7 @@ namespace Microsoft.AspNetCore.Blazor.Build.Test
             var renderer = new TestRenderer();
 
             // Assert
-            Action<UIEventArgs> setter = null;
+            EventCallback setter = default;
             var frames = GetRenderTree(renderer, component);
             Assert.Collection(frames,
                 frame => AssertFrame.Element(frame, "input", 3, 0),
@@ -607,11 +637,16 @@ namespace Microsoft.AspNetCore.Blazor.Build.Test
                 frame =>
                 {
                     AssertFrame.Attribute(frame, "onchange", 2);
-                    setter = Assert.IsType<Action<UIEventArgs>>(frame.AttributeValue);
+                    setter = Assert.IsType<EventCallback>(frame.AttributeValue);
                 });
 
             // Trigger the change event to show it updates the property
-            await renderer.Invoke(() => setter(new UIChangeEventArgs() { Value = MyEnum.SecondValue.ToString(), }));
+            //
+            // This should always complete synchronously.
+            var task = renderer.InvokeAsync(() => setter.InvokeAsync(new UIChangeEventArgs { Value = MyEnum.SecondValue.ToString(), }));
+            Assert.Equal(TaskStatus.RanToCompletion, task.Status);
+            await task;
+
             Assert.Equal(MyEnum.SecondValue, (MyEnum)myValueProperty.GetValue(component));
         }
 

src/Components/Components/src/EventCallbackFactory.cs

@@ -44,11 +44,6 @@ namespace Microsoft.AspNetCore.Components
                 throw new ArgumentNullException(nameof(receiver));
             }
 
-            if (callback == null)
-            {
-                throw new ArgumentNullException(nameof(callback));
-            }
-
             return CreateCore(receiver, callback);
         }
 
@@ -66,11 +61,6 @@ namespace Microsoft.AspNetCore.Components
                 throw new ArgumentNullException(nameof(receiver));
             }
 
-            if (callback == null)
-            {
-                throw new ArgumentNullException(nameof(callback));
-            }
-
             return CreateCore(receiver, callback);
         }
 
@@ -88,11 +78,6 @@ namespace Microsoft.AspNetCore.Components
                 throw new ArgumentNullException(nameof(receiver));
             }
 
-            if (callback == null)
-            {
-                throw new ArgumentNullException(nameof(callback));
-            }
-
             return CreateCore(receiver, callback);
         }
 
@@ -110,11 +95,6 @@ namespace Microsoft.AspNetCore.Components
                 throw new ArgumentNullException(nameof(receiver));
             }
 
-            if (callback == null)
-            {
-                throw new ArgumentNullException(nameof(callback));
-            }
-
             return CreateCore(receiver, callback);
         }
 
@@ -135,6 +115,23 @@ namespace Microsoft.AspNetCore.Components
             return callback;
         }
 
+        /// <summary>
+        /// Returns the provided <paramref name="callback"/>. For internal framework use only.
+        /// </summary>
+        /// <param name="receiver"></param>
+        /// <param name="callback"></param>
+        /// <returns></returns>
+        [EditorBrowsable(EditorBrowsableState.Never)]
+        public EventCallback<T> Create<T>(object receiver, EventCallback callback)
+        {
+            if (receiver == null)
+            {
+                throw new ArgumentNullException(nameof(receiver));
+            }
+
+            return new EventCallback<T>(callback.Receiver, callback.Delegate);
+        }
+
         /// <summary>
         /// Returns the provided <paramref name="callback"/>. For internal framework use only.
         /// </summary>
@@ -166,11 +163,6 @@ namespace Microsoft.AspNetCore.Components
                 throw new ArgumentNullException(nameof(receiver));
             }
 
-            if (callback == null)
-            {
-                throw new ArgumentNullException(nameof(callback));
-            }
-
             return CreateCore<T>(receiver, callback);
         }
 
@@ -188,11 +180,6 @@ namespace Microsoft.AspNetCore.Components
                 throw new ArgumentNullException(nameof(receiver));
             }
 
-            if (callback == null)
-            {
-                throw new ArgumentNullException(nameof(callback));
-            }
-
             return CreateCore<T>(receiver, callback);
         }
 
@@ -210,11 +197,6 @@ namespace Microsoft.AspNetCore.Components
                 throw new ArgumentNullException(nameof(receiver));
             }
 
-            if (callback == null)
-            {
-                throw new ArgumentNullException(nameof(callback));
-            }
-
             return CreateCore<T>(receiver, callback);
         }
 
@@ -232,11 +214,6 @@ namespace Microsoft.AspNetCore.Components
                 throw new ArgumentNullException(nameof(receiver));
             }
 
-            if (callback == null)
-            {
-                throw new ArgumentNullException(nameof(callback));
-            }
-
             return CreateCore<T>(receiver, callback);
         }
 
@@ -270,22 +247,12 @@ namespace Microsoft.AspNetCore.Components
 
         private EventCallback CreateCore(object receiver, MulticastDelegate callback)
         {
-            if (!object.ReferenceEquals(receiver, callback.Target) && receiver is IHandleEvent handler)
+            return new EventCallback(callback?.Target as IHandleEvent ?? receiver as IHandleEvent, callback);
-            {
-                return new EventCallback(handler, callback);
-            }
-
-            return new EventCallback(callback.Target as IHandleEvent, callback);
         }
 
         private EventCallback<T> CreateCore<T>(object receiver, MulticastDelegate callback)
         {
-            if (!object.ReferenceEquals(receiver, callback.Target) && receiver is IHandleEvent handler)
+            return new EventCallback<T>(callback?.Target as IHandleEvent ?? receiver as IHandleEvent, callback);
-            {
-                return new EventCallback<T>(handler, callback);
-            }
-
-            return new EventCallback<T>(callback.Target as IHandleEvent, callback);
         }
     }
 }

src/Components/Components/src/RuntimeHelpers.cs

@@ -2,10 +2,14 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 
+using System;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Components.Forms;
+
 namespace Microsoft.AspNetCore.Components
 {
     /// <summary>
-    /// Used by generated code produced by the Blazor code generator. Not intended or supported
+    /// Used by generated code produced by the Components code generator. Not intended or supported
     /// for use in application code.
     /// </summary>
     public static class RuntimeHelpers
@@ -17,5 +21,502 @@ namespace Microsoft.AspNetCore.Components
         /// <param name="value"></param>
         /// <returns></returns>
         public static T TypeCheck<T>(T value) => value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Action value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Func<Task> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Action<EditContext> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Func<EditContext, Task> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Action<UIEventArgs> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Func<UIEventArgs, Task> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Action<UIChangeEventArgs> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Func<UIChangeEventArgs, Task> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Action<UIClipboardEventArgs> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Func<UIClipboardEventArgs, Task> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Action<UIDataTransferItem> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Func<UIDataTransferItem, Task> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Action<UIDragEventArgs> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Func<UIDragEventArgs, Task> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Action<UIErrorEventArgs> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Func<UIErrorEventArgs, Task> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Action<UIFocusEventArgs> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Func<UIFocusEventArgs, Task> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Action<UIKeyboardEventArgs> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Func<UIKeyboardEventArgs, Task> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Action<UIMouseEventArgs> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Func<UIMouseEventArgs, Task> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Action<UIPointerEventArgs> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Func<UIPointerEventArgs, Task> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Action<UIProgressEventArgs> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Func<UIProgressEventArgs, Task> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Action<UITouchEventArgs> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Func<UITouchEventArgs, Task> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Action<UIWheelEventArgs> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Func<UIWheelEventArgs, Task> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Action<int> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Func<int, Task> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Action<int?> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Func<int?, Task> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Action<long> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Func<long, Task> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Action<long?> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Func<long?, Task> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Action<decimal> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Func<decimal, Task> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Action<decimal?> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Func<decimal?, Task> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Action<float> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Func<float, Task> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Action<float?> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Func<float?, Task> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Action<double> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Func<double, Task> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Action<double?> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Func<double?, Task> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Action<DateTime> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Func<DateTime, Task> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Action<DateTime?> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Func<DateTime?, Task> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Action<bool> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Func<bool, Task> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Action<bool?> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Func<bool?, Task> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Action<string> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Func<string, Task> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Action<object> value) => (T)(object)value;
+
+        /// <summary>
+        /// Not intended for use by application code.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <param name="value"></param>
+        /// <returns></returns>
+        public static T TypeCheck<T>(Func<object, Task> value) => (T)(object)value;
+
     }
 }

src/Components/Components/test/EventCallbackFactoryTest.cs

@@ -58,8 +58,8 @@ namespace Microsoft.AspNetCore.Components
 
             // Assert
             Assert.Same(@delegate, callback.Delegate);
-            Assert.Same(anotherComponent, callback.Receiver);
+            Assert.Same(component, callback.Receiver);
-            Assert.True(callback.RequiresExplicitReceiver);
+            Assert.False(callback.RequiresExplicitReceiver);
         }
 
         [Fact]
@@ -80,6 +80,21 @@ namespace Microsoft.AspNetCore.Components
             Assert.True(callback.RequiresExplicitReceiver);
         }
 
+        [Fact]
+        public void Create_Action_Null()
+        {
+            // Arrange
+            var component = new EventComponent();
+
+            // Act
+            var callback = EventCallback.Factory.Create(component, (Action)null);
+
+            // Assert
+            Assert.Null(callback.Delegate);
+            Assert.Same(component, callback.Receiver);
+            Assert.True(callback.RequiresExplicitReceiver);
+        }
+
         [Fact]
         public void Create_ActionT_AlreadyBoundToReceiver()
         {
@@ -110,8 +125,8 @@ namespace Microsoft.AspNetCore.Components
 
             // Assert
             Assert.Same(@delegate, callback.Delegate);
-            Assert.Same(anotherComponent, callback.Receiver);
+            Assert.Same(component, callback.Receiver);
-            Assert.True(callback.RequiresExplicitReceiver);
+            Assert.False(callback.RequiresExplicitReceiver);
         }
 
         [Fact]
@@ -132,6 +147,21 @@ namespace Microsoft.AspNetCore.Components
             Assert.True(callback.RequiresExplicitReceiver);
         }
 
+        [Fact]
+        public void Create_ActionT_Null()
+        {
+            // Arrange
+            var component = new EventComponent();
+
+            // Act
+            var callback = EventCallback.Factory.Create(component, (Action<string>)null);
+
+            // Assert
+            Assert.Null(callback.Delegate);
+            Assert.Same(component, callback.Receiver);
+            Assert.True(callback.RequiresExplicitReceiver);
+        }
+
         [Fact]
         public void Create_FuncTask_AlreadyBoundToReceiver()
         {
@@ -162,8 +192,8 @@ namespace Microsoft.AspNetCore.Components
 
             // Assert
             Assert.Same(@delegate, callback.Delegate);
-            Assert.Same(anotherComponent, callback.Receiver);
+            Assert.Same(component, callback.Receiver);
-            Assert.True(callback.RequiresExplicitReceiver);
+            Assert.False(callback.RequiresExplicitReceiver);
         }
 
         [Fact]
@@ -200,6 +230,21 @@ namespace Microsoft.AspNetCore.Components
             Assert.False(callback.RequiresExplicitReceiver);
         }
 
+        [Fact]
+        public void Create_FuncTask_Null()
+        {
+            // Arrange
+            var component = new EventComponent();
+
+            // Act
+            var callback = EventCallback.Factory.Create(component, (Func<Task>)null);
+
+            // Assert
+            Assert.Null(callback.Delegate);
+            Assert.Same(component, callback.Receiver);
+            Assert.True(callback.RequiresExplicitReceiver);
+        }
+
         [Fact]
         public void Create_FuncTTask_DifferentReceiver()
         {
@@ -214,8 +259,8 @@ namespace Microsoft.AspNetCore.Components
 
             // Assert
             Assert.Same(@delegate, callback.Delegate);
-            Assert.Same(anotherComponent, callback.Receiver);
+            Assert.Same(component, callback.Receiver);
-            Assert.True(callback.RequiresExplicitReceiver);
+            Assert.False(callback.RequiresExplicitReceiver);
         }
 
         [Fact]
@@ -236,6 +281,21 @@ namespace Microsoft.AspNetCore.Components
             Assert.True(callback.RequiresExplicitReceiver);
         }
 
+        [Fact]
+        public void Create_FuncTTask_Null()
+        {
+            // Arrange
+            var component = new EventComponent();
+
+            // Act
+            var callback = EventCallback.Factory.Create(component, (Func<string, Task>)null);
+
+            // Assert
+            Assert.Null(callback.Delegate);
+            Assert.Same(component, callback.Receiver);
+            Assert.True(callback.RequiresExplicitReceiver);
+        }
+
         [Fact]
         public void CreateT_String_ReturnsInput()
         {
@@ -299,8 +359,8 @@ namespace Microsoft.AspNetCore.Components
 
             // Assert
             Assert.Same(@delegate, callback.Delegate);
-            Assert.Same(anotherComponent, callback.Receiver);
+            Assert.Same(component, callback.Receiver);
-            Assert.True(callback.RequiresExplicitReceiver);
+            Assert.False(callback.RequiresExplicitReceiver);
         }
 
         [Fact]
@@ -321,6 +381,21 @@ namespace Microsoft.AspNetCore.Components
             Assert.True(callback.RequiresExplicitReceiver);
         }
 
+        [Fact]
+        public void CreateT_Action_Null()
+        {
+            // Arrange
+            var component = new EventComponent();
+
+            // Act
+            var callback = EventCallback.Factory.Create<string>(component, (Action)null);
+
+            // Assert
+            Assert.Null(callback.Delegate);
+            Assert.Same(component, callback.Receiver);
+            Assert.True(callback.RequiresExplicitReceiver);
+        }
+
         [Fact]
         public void CreateT_ActionT_AlreadyBoundToReceiver()
         {
@@ -351,7 +426,22 @@ namespace Microsoft.AspNetCore.Components
 
             // Assert
             Assert.Same(@delegate, callback.Delegate);
-            Assert.Same(anotherComponent, callback.Receiver);
+            Assert.Same(component, callback.Receiver);
+            Assert.False(callback.RequiresExplicitReceiver);
+        }
+
+        [Fact]
+        public void CreateT_ActionT_Null()
+        {
+            // Arrange
+            var component = new EventComponent();
+
+            // Act
+            var callback = EventCallback.Factory.Create<string>(component, (Action<string>)null);
+
+            // Assert
+            Assert.Null(callback.Delegate);
+            Assert.Same(component, callback.Receiver);
             Assert.True(callback.RequiresExplicitReceiver);
         }
 
@@ -403,8 +493,8 @@ namespace Microsoft.AspNetCore.Components
 
             // Assert
             Assert.Same(@delegate, callback.Delegate);
-            Assert.Same(anotherComponent, callback.Receiver);
+            Assert.Same(component, callback.Receiver);
-            Assert.True(callback.RequiresExplicitReceiver);
+            Assert.False(callback.RequiresExplicitReceiver);
         }
 
         [Fact]
@@ -425,6 +515,21 @@ namespace Microsoft.AspNetCore.Components
             Assert.True(callback.RequiresExplicitReceiver);
         }
 
+        [Fact]
+        public void CreateT_FuncTask_Null()
+        {
+            // Arrange
+            var component = new EventComponent();
+
+            // Act
+            var callback = EventCallback.Factory.Create<string>(component, (Func<Task>)null);
+
+            // Assert
+            Assert.Null(callback.Delegate);
+            Assert.Same(component, callback.Receiver);
+            Assert.True(callback.RequiresExplicitReceiver);
+        }
+
         [Fact]
         public void CreateT_FuncTTask_AlreadyBoundToReceiver()
         {
@@ -455,8 +560,8 @@ namespace Microsoft.AspNetCore.Components
 
             // Assert
             Assert.Same(@delegate, callback.Delegate);
-            Assert.Same(anotherComponent, callback.Receiver);
+            Assert.Same(component, callback.Receiver);
-            Assert.True(callback.RequiresExplicitReceiver);
+            Assert.False(callback.RequiresExplicitReceiver);
         }
 
         [Fact]
@@ -477,6 +582,21 @@ namespace Microsoft.AspNetCore.Components
             Assert.True(callback.RequiresExplicitReceiver);
         }
 
+        [Fact]
+        public void CreateT_FuncTTask_Null()
+        {
+            // Arrange
+            var component = new EventComponent();
+
+            // Act
+            var callback = EventCallback.Factory.Create<string>(component, (Func<string, Task>)null);
+
+            // Assert
+            Assert.Null(callback.Delegate);
+            Assert.Same(component, callback.Receiver);
+            Assert.True(callback.RequiresExplicitReceiver);
+        }
+
         [Fact]
         public void CreateInferred_ActionT()
         {

src/Components/test/testassets/BasicTestApp/CascadingValueTest/CascadingValueReceiveFixedByInterface.cshtml

@@ -11,6 +11,8 @@
 <p>
     @(nameof(CascadingValueReceiveFixedByInterface)) render count:
     <strong id="receive-by-interface-num-renders">@numRenders</strong>
+
+    @* Prevent rerendering this component when the button is clicked. *@
     <button id="decrement-count" onclick=@Ancestor.DecrementCount>Decrement</button>
 </p>
 

src/Components/test/testassets/BasicTestApp/EventCallbackTest/EventCallbackCases.cshtml

@@ -10,29 +10,29 @@
 </div>
 <div id="capturing_lambda">
     <h3>Passing Capturing Lambda to Button</h3>
-    <InnerButton OnClick="@EventCallback.Factory.Create(this, () => { GC.KeepAlive(this); })" Text="Capturing Lambda" />
+    <InnerButton OnClick="@(() => { GC.KeepAlive(this); })" Text="Capturing Lambda" />
 </div>
 <div id="unbound_lambda">
     <h3>Passing Unbound Lambda to Button</h3>
-    <InnerButton OnClick="@EventCallback.Factory.Create(this, () => { })" Text="Unbound Lambda" />
+    <InnerButton OnClick="@(() => { })" Text="Unbound Lambda" />
 </div>
 <div id="unbound_lambda_nested">
     <h3>Passing Unbound Lambda to Nested Button</h3>
-    <MiddleButton OnClick="@EventCallback.Factory.Create(this, () => { })" Text="Unbound Lambda Nested" />
+    <MiddleButton OnClick="@(() => { })" Text="Unbound Lambda Nested" />
 </div>
 <div id="unbound_lambda_strongly_typed">
     <h3>Passing Capturing Lambda to Strongly Typed Button</h3>
-    <StronglyTypedButton OnClick="@(EventCallback.Factory.Create<UIMouseEventArgs>(this, () => { GC.KeepAlive(this); }))" Text="Unbound Lambda Strongly-Typed" />
+    <StronglyTypedButton OnClick="@(() => { GC.KeepAlive(this); })" Text="Unbound Lambda Strongly-Typed" />
 </div>
 <div id="unbound_lambda_child_content">
     <h3>Passing Child Content</h3>
     <TemplatedControl>
-        <button onclick="@EventCallback.Factory.Create(this, () => { })">Unbound Lambda Child Content</button>
+        <button onclick="@(() => { })">Unbound Lambda Child Content</button>
     </TemplatedControl>
 </div>
 <div id="unbound_lambda_bind_to_component">
     <h3>Passing Child Content</h3>
-    <ButtonComponent Count="@buttonComponentCount" CountChanged="@(EventCallback.Factory.Create<int>(this, () => { }))" Text="Unbound Lambda Bind-To-Component" />
+    <ButtonComponent bind-Count="buttonComponentCount" Text="Unbound Lambda Bind-To-Component" />
 </div>
 
 @functions {

src/Components/test/testassets/BasicTestApp/FormsTest/SimpleValidationComponent.cshtml

@@ -1,7 +1,7 @@
 @using System.ComponentModel.DataAnnotations
 @using Microsoft.AspNetCore.Components.Forms
 
-<EditForm Model="@this" OnValidSubmit="@(EventCallback.Factory.Create<EditContext>(this, HandleValidSubmit))" OnInvalidSubmit="@(EventCallback.Factory.Create<EditContext>(this, HandleInvalidSubmit))">
+<EditForm Model="@this" OnValidSubmit="@HandleValidSubmit" OnInvalidSubmit="@HandleInvalidSubmit">
     <DataAnnotationsValidator />
 
     <p class="user-name">

src/Components/test/testassets/BasicTestApp/FormsTest/TypicalValidationComponent.cshtml

@@ -1,34 +1,34 @@
 @using System.ComponentModel.DataAnnotations
 @using Microsoft.AspNetCore.Components.Forms
 
-<EditForm Model="@person" OnValidSubmit="@(EventCallback.Factory.Create<EditContext>(this, HandleValidSubmit))">
+<EditForm Model="@person" OnValidSubmit="@HandleValidSubmit">
     <DataAnnotationsValidator />
 
     <p class="name">
-        Name: <InputText bind-Value="@person.Name" ValueExpression="@(() => person.Name)" />
+        Name: <InputText bind-Value="@person.Name" />
     </p>
     <p class="email">
-        Email: <InputText bind-Value="@person.Email" ValueExpression="@(() => person.Email)" />
+        Email: <InputText bind-Value="@person.Email" />
         <ValidationMessage For="@(() => person.Email)" />
     </p>
     <p class="age">
-        Age (years): <InputNumber bind-Value="@person.AgeInYears" ValueExpression="@(() => person.AgeInYears)" />
+        Age (years): <InputNumber bind-Value="@person.AgeInYears" />
     </p>
     <p class="height">
-        Height (optional): <InputNumber bind-Value="@person.OptionalHeight" ValueExpression="@(() => person.OptionalHeight)" />
+        Height (optional): <InputNumber bind-Value="@person.OptionalHeight" />
     </p>
     <p class="description">
-        Description: <InputTextArea bind-Value="@person.Description" ValueExpression="@(() => person.Description)" />
+        Description: <InputTextArea bind-Value="@person.Description" />
     </p>
     <p class="renewal-date">
-        Renewal date: <InputDate bind-Value="@person.RenewalDate" ValueExpression="@(() => person.RenewalDate)" />
+        Renewal date: <InputDate bind-Value="@person.RenewalDate" />
     </p>
     <p class="expiry-date">
-        Expiry date (optional): <InputDate bind-Value="@person.OptionalExpiryDate" ValueExpression="@(() => person.OptionalExpiryDate)" />
+        Expiry date (optional): <InputDate bind-Value="@person.OptionalExpiryDate" />
     </p>
     <p class="ticket-class">
         Ticket class:
-        <InputSelect bind-Value="@person.TicketClass" ValueExpression="@(() => person.TicketClass)">
+        <InputSelect bind-Value="@person.TicketClass">
             <option>(select)</option>
             <option value="@TicketClass.Economy">Economy class</option>
             <option value="@TicketClass.Premium">Premium class</option>
@@ -36,7 +36,7 @@
         </InputSelect>
     </p>
     <p class="accepts-terms">
-        Accepts terms: <InputCheckbox bind-Value="@person.AcceptsTerms" ValueExpression="@(() => person.AcceptsTerms)" />
+        Accepts terms: <InputCheckbox bind-Value="@person.AcceptsTerms" />
     </p>
 
     <button type="submit">Submit</button>