Part of #2151 - Remove [Activate] from ViewComponents

This change removes [Activate] from ViewComponents. Accessing context
should be done through [ViewComponentContext]. Accessing services should
be done though constructor injection.

src/Microsoft.AspNet.Mvc.Core/ViewComponents/DefaultViewComponentActivator.cs

@@ -3,40 +3,43 @@
 
 using System;
 using System.Collections.Concurrent;
-using System.Collections.Generic;
 using System.Reflection;
-using Microsoft.AspNet.Mvc.Rendering;
-using Microsoft.Framework.DependencyInjection;
 using Microsoft.Framework.Internal;
 
 namespace Microsoft.AspNet.Mvc.ViewComponents
 {
     /// <summary>
-    /// Represents the <see cref="IViewComponentActivator"/> that is registered by default.
+    /// A default implementation of <see cref="IViewComponentActivator"/>.
     /// </summary>
+    /// <remarks>
+    /// The <see cref="DefaultViewComponentActivator"/> can provide the current instance of
+    /// <see cref="ViewComponentContext"/> to a public property of a view component marked
+    /// with <see cref="ViewComponentContextAttribute"/>. 
+    /// </remarks>
     public class DefaultViewComponentActivator : IViewComponentActivator
     {
-        private readonly Func<Type, PropertyActivator<ViewContext>[]> _getPropertiesToActivate;
+        private readonly Func<Type, PropertyActivator<ViewComponentContext>[]> _getPropertiesToActivate;
-        private readonly IDictionary<Type, Func<ViewContext, object>> _valueAccessorLookup;
+        private readonly ConcurrentDictionary<Type, PropertyActivator<ViewComponentContext>[]> _injectActions;
-        private readonly ConcurrentDictionary<Type, PropertyActivator<ViewContext>[]> _injectActions;
 
         /// <summary>
         /// Initializes a new instance of <see cref="DefaultViewComponentActivator"/> class.
         /// </summary>
         public DefaultViewComponentActivator()
         {
-            _valueAccessorLookup = CreateValueAccessorLookup();
+            _injectActions = new ConcurrentDictionary<Type, PropertyActivator<ViewComponentContext>[]>();
-            _injectActions = new ConcurrentDictionary<Type, PropertyActivator<ViewContext>[]>();
             _getPropertiesToActivate = type =>
-                PropertyActivator<ViewContext>.GetPropertiesToActivate(
+                PropertyActivator<ViewComponentContext>.GetPropertiesToActivate(
-                    type, typeof(ActivateAttribute), CreateActivateInfo);
+                    type,
+                    typeof(ViewComponentContextAttribute),
+                    CreateActivateInfo);
         }
 
         /// <inheritdoc />
-        public virtual void Activate([NotNull] object viewComponent, [NotNull] ViewContext context)
+        public virtual void Activate([NotNull] object viewComponent, [NotNull] ViewComponentContext context)
         {
-            var propertiesToActivate = _injectActions.GetOrAdd(viewComponent.GetType(),
+            var propertiesToActivate = _injectActions.GetOrAdd(
-                                                               _getPropertiesToActivate);
+                viewComponent.GetType(),
+                _getPropertiesToActivate);
 
             for (var i = 0; i < propertiesToActivate.Length; i++)
             {
@@ -45,44 +48,9 @@ namespace Microsoft.AspNet.Mvc.ViewComponents
             }
         }
 
-        /// <summary>
+        private PropertyActivator<ViewComponentContext> CreateActivateInfo(PropertyInfo property)
-        /// Creates a lookup dictionary for the values to be activated.
-        /// </summary>
-        /// <returns>Returns a readonly dictionary of the values corresponding to the types.</returns>
-        protected virtual IDictionary<Type, Func<ViewContext, object>> CreateValueAccessorLookup()
         {
-            return new Dictionary<Type, Func<ViewContext, object>>
+            return new PropertyActivator<ViewComponentContext>(property, context => context);
-            {
-                { typeof(ViewContext), (context) => context },
-                {
-                    typeof(ViewDataDictionary),
-                    (context) =>
-                    {
-                        return new ViewDataDictionary(context.ViewData);
-                    }
-                }
-            };
-        }
-
-        private PropertyActivator<ViewContext> CreateActivateInfo(PropertyInfo property)
-        {
-            Func<ViewContext, object> valueAccessor;
-            if (!_valueAccessorLookup.TryGetValue(property.PropertyType, out valueAccessor))
-            {
-                valueAccessor = (viewContext) =>
-                {
-                    var serviceProvider = viewContext.HttpContext.RequestServices;
-                    var service = serviceProvider.GetRequiredService(property.PropertyType);
-                    if (typeof(ICanHasViewContext).IsAssignableFrom(property.PropertyType))
-                    {
-                        ((ICanHasViewContext)service).Contextualize(viewContext);
-                    }
-
-                    return service;
-                };
-            }
-
-            return new PropertyActivator<ViewContext>(property, valueAccessor);
         }
     }
 }

src/Microsoft.AspNet.Mvc.Core/ViewComponents/DefaultViewComponentInvoker.cs

@@ -80,7 +80,7 @@ namespace Microsoft.AspNet.Mvc.ViewComponents
             var component = _typeActivatorCache.CreateInstance<object>(
                 _serviceProvider, 
                 context.ViewComponentDescriptor.Type);
-            _viewComponentActivator.Activate(component, context.ViewContext);
+            _viewComponentActivator.Activate(component, context);
             return component;
         }
 

src/Microsoft.AspNet.Mvc.Core/ViewComponents/IViewComponentActivator.cs

@@ -12,7 +12,9 @@ namespace Microsoft.AspNet.Mvc.ViewComponents
         /// When implemented in a type, activates an instantiated ViewComponent.
         /// </summary>
         /// <param name="viewComponent">The ViewComponent to activate.</param>
-        /// <param name="context">The <see cref="ViewContext"/> for the executing <see cref="ViewComponent"/>.</param>
+        /// <param name="context">
-        void Activate(object viewComponent, ViewContext context);
+        /// The <see cref="ViewComponentContext"/> for the executing <see cref="ViewComponent"/>.
+        /// </param>
+        void Activate(object viewComponent, ViewComponentContext context);
     }
 }

src/Microsoft.AspNet.Mvc.Core/ViewComponents/ViewComponent.cs

@@ -6,7 +6,9 @@ using System.Security.Principal;
 using Microsoft.AspNet.Http;
 using Microsoft.AspNet.Mvc.ModelBinding;
 using Microsoft.AspNet.Mvc.Rendering;
+using Microsoft.AspNet.Mvc.ViewComponents;
 using Microsoft.AspNet.Routing;
+using Microsoft.Framework.DependencyInjection;
 using Microsoft.Framework.Internal;
 using Newtonsoft.Json;
 
@@ -18,9 +20,10 @@ namespace Microsoft.AspNet.Mvc
     [ViewComponent]
     public abstract class ViewComponent
     {
+        private IUrlHelper _url;
         private dynamic _viewBag;
-        private ViewContext _viewContext;
+        private ViewComponentContext _viewComponentContext;
-        private ViewDataDictionary _viewData;
+        private ICompositeViewEngine _viewEngine;
 
         /// <summary>
         /// Gets the <see cref="HttpContext"/>.
@@ -96,62 +99,93 @@ namespace Microsoft.AspNet.Mvc
         /// <summary>
         /// Gets or sets the <see cref="IUrlHelper"/>.
         /// </summary>
-        [Activate]
+        public IUrlHelper Url
-        public IUrlHelper Url { get; set; }
-
-        /// <summary>
-        /// Gets or sets the <see cref="ViewContext"/>.
-        /// </summary>
-        [Activate]
-        public ViewContext ViewContext
         {
             get
             {
-                if (_viewContext == null)
+                if (_url == null)
                 {
-                    // This should run only for the ViewComponent unit test scenarios
+                    // May be null in unit-testing scenarios.
-                    _viewContext = new ViewContext();
+                    var services = ViewComponentContext.ViewContext?.HttpContext?.RequestServices;
+                    _url = services?.GetRequiredService<IUrlHelper>();
                 }
 
-                return _viewContext;
+                return _url;
             }
 
             [param: NotNull]
             set
             {
-                _viewContext = value;
+                _url = value;
+            }
+        }
+
+        [ViewComponentContext]
+        public ViewComponentContext ViewComponentContext
+        {
+            get
+            {
+                // This should run only for the ViewComponent unit test scenarios.
+                if (_viewComponentContext == null)
+                {
+                    _viewComponentContext = new ViewComponentContext();
+                }
+
+                return _viewComponentContext;
+            }
+
+            [param: NotNull]
+            set
+            {
+                _viewComponentContext = value;
             }
         }
 
         /// <summary>
-        /// Gets or sets the <see cref="ViewDataDictionary"/>.
+        /// Gets the <see cref="ViewContext"/>.
+        /// </summary>
+        public ViewContext ViewContext
+        {
+            get
+            {
+                return ViewComponentContext.ViewContext;
+            }
+        }
+
+        /// <summary>
+        /// Gets the <see cref="ViewDataDictionary"/>.
         /// </summary>
-        [Activate]
         public ViewDataDictionary ViewData
         {
             get
             {
-                if (_viewData == null)
+                return ViewComponentContext.ViewData;
-                {
-                    // This should run only for the ViewComponent unit test scenarios
-                    _viewData = new ViewDataDictionary(ViewContext.ViewData);
-                }
-
-                return _viewData;
-            }
-
-            [param: NotNull]
-            set
-            {
-                _viewData = value;
             }
         }
 
         /// <summary>
         /// Gets or sets the <see cref="ICompositeViewEngine"/>.
         /// </summary>
-        [Activate]
+        public ICompositeViewEngine ViewEngine
-        public ICompositeViewEngine ViewEngine { get; set; }
+        {
+            get
+            {
+                if (_viewEngine == null)
+                {
+                    // May be null in unit-testing scenarios.
+                    var services = ViewComponentContext.ViewContext?.HttpContext?.RequestServices;
+                    _viewEngine = services?.GetRequiredService<ICompositeViewEngine>();
+                }
+
+                return _viewEngine;
+            }
+
+            [param: NotNull]
+            set
+            {
+                _viewEngine = value;
+            }
+        }
 
         /// <summary>
         /// Returns a result which will render HTML encoded text.

src/Microsoft.AspNet.Mvc.Core/ViewComponents/ViewComponentContext.cs

@@ -12,6 +12,19 @@ namespace Microsoft.AspNet.Mvc
     /// </summary>
     public class ViewComponentContext
     {
+        /// <summary>
+        /// Creates a new <see cref="ViewComponentContext"/>.
+        /// </summary>
+        /// <remarks>
+        /// The default constructor is provided for unit test purposes only.
+        /// </remarks>
+        public ViewComponentContext()
+        {
+            ViewComponentDescriptor = new ViewComponentDescriptor();
+            Arguments = new object[0];
+            ViewContext = new ViewContext();
+        }
+
         /// <summary>
         /// Creates a new <see cref="ViewComponentContext"/>.
         /// </summary>
@@ -29,32 +42,54 @@ namespace Microsoft.AspNet.Mvc
         {
             ViewComponentDescriptor = viewComponentDescriptor;
             Arguments = arguments;
-            ViewContext = viewContext;
+
-            Writer = writer;
+            // We want to create a defensive copy of the VDD here so that changes done in the VC
+            // aren't visible in the calling view.
+            ViewContext = new ViewContext(
+                viewContext,
+                viewContext.View, 
+                new ViewDataDictionary(viewContext.ViewData),
+                writer);
         }
 
         /// <summary>
-        /// Gets the View Component arguments. 
+        /// Gets or sets the View Component arguments. 
-        /// </summary>
-        public object[] Arguments { get; }
-
-        /// <summary>
-        /// Gets the <see cref="ViewComponentDescriptor"/> for the View Component being invoked.
-        /// </summary>
-        public ViewComponentDescriptor ViewComponentDescriptor { get; }
-
-        /// <summary>
-        /// Gets the <see cref="ViewContext"/>.
-        /// </summary>
-        public ViewContext ViewContext { get; }
-
-        /// <summary>
-        /// Gets the <see cref="TextWriter"/> for writing output.
         /// </summary>
         /// <remarks>
-        /// <see cref="IViewComponentHelper.Invoke(string, object[])"/> or a similar overload is used to invoke the
+        /// The property setter is provided for unit test purposes only.
-        /// View Component, then <see cref="Writer"/> will be different than <see cref="ViewContext.Writer"/>.
         /// </remarks>
-        public TextWriter Writer { get; }
+        public object[] Arguments { get; set; }
+
+        /// <summary>
+        /// Gets or sets the <see cref="ViewComponentDescriptor"/> for the View Component being invoked.
+        /// </summary>
+        /// <remarks>
+        /// The property setter is provided for unit test purposes only.
+        /// </remarks>
+        public ViewComponentDescriptor ViewComponentDescriptor { get; set; }
+
+        /// <summary>
+        /// Gets or sets the <see cref="ViewContext"/>.
+        /// </summary>
+        /// <remarks>
+        /// The property setter is provided for unit test purposes only.
+        /// </remarks>
+        public ViewContext ViewContext { get; set; }
+
+        /// <summary>
+        /// Gets the <see cref="ViewDataDictionary"/>.
+        /// </summary>
+        /// <remarks>
+        /// This is an alias for <c>ViewContext.ViewData</c>.
+        /// </remarks>
+        public ViewDataDictionary ViewData => ViewContext.ViewData;
+
+        /// <summary>
+        /// Gets the <see cref="TextWriter"/> for output.
+        /// </summary>
+        /// <remarks>
+        /// This is an alias for <c>ViewContext.Writer</c>.
+        /// </remarks>
+        public TextWriter Writer => ViewContext.Writer;
     }
 }

src/Microsoft.AspNet.Mvc.Core/ViewComponents/ViewComponentContextAttribute.cs

@@ -0,0 +1,17 @@
+// 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;
+
+namespace Microsoft.AspNet.Mvc.ViewComponents
+{
+    /// <summary>
+    /// Specifies that a controller property should be set with the current
+    /// <see cref="ViewComponentContext"/> when creating the view component. The property must have a public
+    /// set method.
+    /// </summary>
+    [AttributeUsage(AttributeTargets.Property, AllowMultiple = false, Inherited = true)]
+    public class ViewComponentContextAttribute : Attribute
+    {
+    }
+}

src/Microsoft.AspNet.Mvc.Core/ViewComponents/ViewViewComponentResult.cs

@@ -62,7 +62,7 @@ namespace Microsoft.AspNet.Mvc
         public async Task ExecuteAsync([NotNull] ViewComponentContext context)
         {
             var viewEngine = ViewEngine ?? ResolveViewEngine(context);
-            var viewData = ViewData ?? context.ViewContext.ViewData;
+            var viewData = ViewData ?? context.ViewData;
 
             string qualifiedViewName;
             if (ViewName != null && ViewName.Length > 0 && ViewName[0] == '/')
@@ -95,7 +95,7 @@ namespace Microsoft.AspNet.Mvc
             var childViewContext = new ViewContext(
                 context.ViewContext,
                 view,
-                ViewData ?? context.ViewContext.ViewData,
+                ViewData ?? context.ViewData,
                 context.Writer);
 
             using (view as IDisposable)

test/Microsoft.AspNet.Mvc.Core.Test/ViewComponentTests.cs

@@ -14,10 +14,7 @@ namespace Microsoft.AspNet.Mvc
         public void ViewComponent_ViewBag_UsesViewData()
         {
             // Arrange
-            var viewComponent = new TestViewComponent()
+            var viewComponent = new TestViewComponent();
-            {
-                ViewData = new ViewDataDictionary(metadataProvider: new EmptyModelMetadataProvider()),
-            };
 
             // Act
             viewComponent.ViewBag.A = "Alice";
@@ -33,10 +30,7 @@ namespace Microsoft.AspNet.Mvc
         public void ViewComponent_ViewData_StoresDataForViewBag()
         {
             // Arrange
-            var viewComponent = new TestViewComponent()
+            var viewComponent = new TestViewComponent();
-            {
-                ViewData = new ViewDataDictionary(metadataProvider: new EmptyModelMetadataProvider()),
-            };
 
             // Act
             viewComponent.ViewData["A"] = "Alice";
@@ -84,10 +78,7 @@ namespace Microsoft.AspNet.Mvc
         public void ViewComponent_View_WithEmptyParameter_SetsResultViewWithDefaultViewName()
         {
             // Arrange
-            var viewComponent = new TestViewComponent()
+            var viewComponent = new TestViewComponent();
-            {
-                ViewData = new ViewDataDictionary(new EmptyModelMetadataProvider()),
-            };
 
             // Act
             var actualResult = viewComponent.View();
@@ -104,10 +95,7 @@ namespace Microsoft.AspNet.Mvc
         public void ViewComponent_View_WithViewNameParameter_SetsResultViewWithCustomViewName()
         {
             // Arrange
-            var viewComponent = new TestViewComponent()
+            var viewComponent = new TestViewComponent();
-            {
-                ViewData = new ViewDataDictionary(new EmptyModelMetadataProvider()),
-            };
 
             // Act
             var actualResult = viewComponent.View("CustomViewName");
@@ -125,10 +113,8 @@ namespace Microsoft.AspNet.Mvc
         public void ViewComponent_View_WithModelParameter_SetsResultViewWithDefaultViewNameAndModel()
         {
             // Arrange
-            var viewComponent = new TestViewComponent()
+            var viewComponent = new TestViewComponent();
-            {
+
-                ViewData = new ViewDataDictionary(new EmptyModelMetadataProvider()),
-            };
             var model = new object();
 
             // Act
@@ -147,10 +133,8 @@ namespace Microsoft.AspNet.Mvc
         public void ViewComponent_View_WithViewNameAndModelParameters_SetsResultViewWithCustomViewNameAndModel()
         {
             // Arrange
-            var viewComponent = new TestViewComponent()
+            var viewComponent = new TestViewComponent();
-            {
+
-                ViewData = new ViewDataDictionary(new EmptyModelMetadataProvider()),
-            };
             var model = new object();
 
             // Act
@@ -180,7 +164,7 @@ namespace Microsoft.AspNet.Mvc
             Assert.Empty(viewComponent.ViewContext.ViewData);
             Assert.NotNull(viewComponent.ViewData);
             Assert.Empty(viewComponent.ViewData);
-            Assert.NotSame(viewComponent.ViewData, viewComponent.ViewContext.ViewData);
+            Assert.Same(viewComponent.ViewData, viewComponent.ViewContext.ViewData);
         }
 
         private class TestViewComponent : ViewComponent

test/Microsoft.AspNet.Mvc.Core.Test/ViewComponents/DefaultViewComponentActivatorTests.cs

@@ -17,135 +17,28 @@ namespace Microsoft.AspNet.Mvc.ViewComponents
     public class DefaultViewComponentActivatorTests
     {
         [Fact]
-        public void DefaultViewComponentActivatorSetsAllPropertiesMarkedAsActivate()
+        public void DefaultViewComponentActivator_ActivatesViewComponentContext()
         {
             // Arrange
             var activator = new DefaultViewComponentActivator();
+
+            var context = new ViewComponentContext();
             var instance = new TestViewComponent();
-            var helper = Mock.Of<IHtmlHelper<object>>();
-            var serviceProvider = new Mock<IServiceProvider>();
-            serviceProvider.Setup(p => p.GetService(typeof(IHtmlHelper<object>))).Returns(helper);
-            serviceProvider.Setup(p => p.GetService(typeof(ICompositeViewEngine))).Returns(Mock.Of<ICompositeViewEngine>());
-            serviceProvider.Setup(p => p.GetService(typeof(IUrlHelper))).Returns(Mock.Of<IUrlHelper>());
-            var viewContext = GetViewContext(serviceProvider.Object);
 
             // Act
-            activator.Activate(instance, viewContext);
+            activator.Activate(instance, context);
 
             // Assert
-            Assert.Same(helper, instance.Html);
+            Assert.Same(context, instance.ViewComponentContext);
-            Assert.Same(viewContext, instance.ViewContext);
-            Assert.IsType<ViewDataDictionary>(instance.ViewData);
-        }
-
-        [Fact]
-        public void DefaultViewComponentActivatorSetsModelAsNull()
-        {
-            // Arrange
-            var activator = new DefaultViewComponentActivator();
-            var helper = Mock.Of<IHtmlHelper<object>>();
-            var serviceProvider = new Mock<IServiceProvider>();
-            serviceProvider.Setup(p => p.GetService(typeof(IHtmlHelper<object>))).Returns(helper);
-            serviceProvider.Setup(p => p.GetService(typeof(ICompositeViewEngine))).Returns(Mock.Of<ICompositeViewEngine>());
-            serviceProvider.Setup(p => p.GetService(typeof(IUrlHelper))).Returns(Mock.Of<IUrlHelper>());
-            var viewContext = GetViewContext(serviceProvider.Object);
-
-            // Act
-            activator.Activate(new TestViewComponent(), viewContext);
-
-            // Assert
-            Assert.Null(viewContext.ViewData.Model);
-        }
-
-        [Fact]
-        public void DefaultViewComponentActivatorActivatesNonBuiltInTypes()
-        {
-            // Arrange
-            var activator = new DefaultViewComponentActivator();
-            var helper = Mock.Of<IHtmlHelper<object>>();
-            var myTestService = new MyService();
-            var serviceProvider = new Mock<IServiceProvider>();
-            serviceProvider.Setup(p => p.GetService(typeof(IHtmlHelper<object>))).Returns(helper);
-            serviceProvider.Setup(p => p.GetService(typeof(MyService))).Returns(myTestService);
-            serviceProvider.Setup(p => p.GetService(typeof(ICompositeViewEngine))).Returns(Mock.Of<ICompositeViewEngine>());
-            serviceProvider.Setup(p => p.GetService(typeof(IUrlHelper))).Returns(Mock.Of<IUrlHelper>());
-            var viewContext = GetViewContext(serviceProvider.Object);
-            var instance = new TestViewComponentWithCustomDataType();
-
-            // Act
-            activator.Activate(instance, viewContext);
-
-            // Assert
-            Assert.Equal(myTestService, instance.TestMyServiceObject);
-
-        }
-
-        [Fact]
-        public void DefaulViewComponentActivatorContextualizesService()
-        {
-            // Arrange
-            var activator = new DefaultViewComponentActivator();
-            var instance = new TestClassUsingMyService();
-            var myTestService = new MyService();
-            var serviceProvider = new Mock<IServiceProvider>();
-            serviceProvider.Setup(p => p.GetService(typeof(MyService))).Returns(myTestService);
-            var viewContext = GetViewContext(serviceProvider.Object);
-
-            // Act
-            activator.Activate(instance, viewContext);
-
-            // Assert
-            Assert.Same(myTestService, instance.MyTestService);
-            Assert.Same(viewContext, instance.MyTestService.ViewContext);
-        }
-
-        private ViewContext GetViewContext(IServiceProvider serviceProvider)
-        {
-            var httpContext = new Mock<DefaultHttpContext>();
-            httpContext.SetupGet(c => c.RequestServices)
-                       .Returns(serviceProvider);
-
-            var actionContext = new ActionContext(httpContext.Object, new RouteData(), new ActionDescriptor());
-            return new ViewContext(actionContext,
-                                              Mock.Of<IView>(),
-                                              new ViewDataDictionary(new EmptyModelMetadataProvider()),
-                                              null,
-                                              TextWriter.Null,
-                                              new HtmlHelperOptions());
         }
 
         private class TestViewComponent : ViewComponent
         {
-            [Activate]
-            public IHtmlHelper<object> Html { get; private set; }
-
             public Task ExecuteAsync()
             {
                 throw new NotImplementedException();
             }
         }
-
-        private class TestViewComponentWithCustomDataType : TestViewComponent
-        {
-            [Activate]
-            public MyService TestMyServiceObject { get; set; }
-        }
-
-        private class MyService : ICanHasViewContext
-        {
-            public ViewContext ViewContext { get; private set; }
-
-            public void Contextualize(ViewContext viewContext)
-            {
-                ViewContext = viewContext;
-            }
-        }
-
-        private class TestClassUsingMyService
-        {
-            [Activate]
-            public MyService MyTestService { get; set; }
-        }
     }
 }
 #endif

test/Microsoft.AspNet.Mvc.FunctionalTests/ActivatorTests.cs

@@ -113,7 +113,7 @@ namespace Microsoft.AspNet.Mvc.FunctionalTests
         }
 
         [Fact]
-        public async Task ViewComponentActivator_ActivatesProperties()
+        public async Task ViewComponentActivator_Activates()
         {
             // Arrange
             var server = TestHelper.CreateServer(_app, SiteName, _configureServices);
@@ -127,35 +127,6 @@ namespace Microsoft.AspNet.Mvc.FunctionalTests
             Assert.Equal(expected, body.Trim());
         }
 
-        [Fact]
-        public async Task ViewComponentActivator_ActivatesPropertiesAndContextualizesThem()
-        {
-            // Arrange
-            var server = TestHelper.CreateServer(_app, SiteName, _configureServices);
-            var client = server.CreateClient();
-            var expected = "test-value";
-
-            // Act
-            var body = await client.GetStringAsync("http://localhost/View/ConsumeValueComponent?test=test-value");
-
-            // Assert
-            Assert.Equal(expected, body.Trim());
-        }
-
-        [Fact]
-        public async Task ViewComponentActivator_ActivatesPropertiesAndContextualizesThem_WhenMultiplePropertiesArePresent()
-        {
-            // Arrange
-            var server = TestHelper.CreateServer(_app, SiteName, _configureServices);
-            var client = server.CreateClient();
-            var expected = "Random Number:4 test-value";
-
-            // Act
-            var body = await client.GetStringAsync("http://localhost/View/ConsumeViewAndValueComponent?test=test-value");
-
-            // Assert
-            Assert.Equal(expected, body.Trim());
-        }
 
         [Fact]
         public async Task ViewComponentThatCannotBeActivated_ThrowsWhenAttemptedToBeInvoked()
@@ -163,8 +134,9 @@ namespace Microsoft.AspNet.Mvc.FunctionalTests
             // Arrange
             var server = TestHelper.CreateServer(_app, SiteName, _configureServices);
             var client = server.CreateClient();
-            var expectedMessage = "No service for type 'ActivatorWebSite.CannotBeActivatedComponent+FakeType' " +
+            var expectedMessage =
-                                   "has been registered.";
+                "Unable to resolve service for type 'ActivatorWebSite.CannotBeActivatedComponent+FakeType' " +
+                "while attempting to activate 'ActivatorWebSite.CannotBeActivatedComponent'.";
 
             // Act & Assert
             var response = await client.GetAsync("http://localhost/View/ConsumeCannotBeActivatedComponent");

test/WebSites/ActivatorWebSite/Components/CannotBeActivatedComponent.cs

@@ -8,15 +8,16 @@ namespace ActivatorWebSite
     [ViewComponent(Name = "CannotBeActivated")]
     public class CannotBeActivatedComponent : ViewComponent
     {
-        [Activate]
+        public CannotBeActivatedComponent(FakeType fakeType)
-        private FakeType Service { get; set; }
+        {
+        }
 
         public IViewComponentResult Invoke()
         {
             return Content("Test");
         }
 
-        private sealed class FakeType
+        public sealed class FakeType
         {
         }
     }

test/WebSites/ActivatorWebSite/Components/NumberComponent.cs

@@ -8,8 +8,12 @@ namespace ActivatorWebSite
     [ViewComponent(Name = "Number")]
     public class NumberComponent : ViewComponent
     {
-        [Activate]
+        public NumberComponent(MyService myTestService)
-        public MyService MyTestService { get; set; }
+        {
+            MyTestService = myTestService;
+        }
+
+        private MyService MyTestService { get; }
 
         public IViewComponentResult Invoke(string content)
         {

test/WebSites/ActivatorWebSite/Components/ValueComponent.cs

@@ -1,19 +0,0 @@
-// 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 Microsoft.AspNet.Mvc;
-
-namespace ActivatorWebSite
-{
-    [ViewComponent(Name = "Value")]
-    public class ValueComponent : ViewComponent
-    {
-        [Activate]
-        public ViewService MyViewService { get; set; }
-
-        public IViewComponentResult Invoke()
-        {
-            return Content(MyViewService.GetValue());
-        }
-    }
-}

test/WebSites/ActivatorWebSite/Components/ViewAndValueComponent.cs

@@ -1,22 +0,0 @@
-// 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 Microsoft.AspNet.Mvc;
-
-namespace ActivatorWebSite
-{
-    [ViewComponent(Name = "ViewAndValue")]
-    public class ViewAndValueComponent : ViewComponent
-    {
-        [Activate]
-        public MyService MySampleService { get; set; }
-
-        [Activate]
-        public ViewService MyViewService { get; set; }
-
-        public IViewComponentResult Invoke(string content)
-        {
-            return Content(content + ":" + MySampleService.Random + " " + MyViewService.GetValue());
-        }
-    }
-}

test/WebSites/ActivatorWebSite/Controllers/ViewController.cs

@@ -31,16 +31,6 @@ namespace ActivatorWebSite
             return View();
         }
 
-        public ViewResult ConsumeValueComponent()
-        {
-            return View();
-        }
-
-        public ViewResult ConsumeViewAndValueComponent()
-        {
-            return View();
-        }
-
         public ViewResult ConsumeCannotBeActivatedComponent()
         {
             return View();

test/WebSites/ActivatorWebSite/Views/View/ConsumeValueComponent.cshtml

@@ -1 +0,0 @@
-@Component.Invoke("Value")

test/WebSites/ActivatorWebSite/Views/View/ConsumeViewAndValueComponent.cshtml

@@ -1 +0,0 @@
-@Component.Invoke("ViewAndValue", "Random Number")

test/WebSites/MvcTagHelpersWebSite/Components/ProductsViewComponent.cs

@@ -9,11 +9,15 @@ namespace MvcTagHelpersWebSite.Components
 {
     public class ProductsViewComponent : ViewComponent
     {
-        [Activate]
+        public ProductsViewComponent(ProductsService productsService, IMemoryCache cache)
-        public ProductsService ProductsService { get; set; }
+        {
+            ProductsService = productsService;
+            Cache = cache;
+        }
 
-        [Activate]
+        private ProductsService ProductsService { get; }
-        public IMemoryCache Cache { get; set; }
+
+        public IMemoryCache Cache { get; }
 
         public IViewComponentResult Invoke(string category)
         {

test/WebSites/RequestServicesWebSite/RequestIdViewComponent.cs

@@ -7,8 +7,12 @@ namespace RequestServicesWebSite
 {
     public class RequestIdViewComponent : ViewComponent
     {
-        [Activate]
+        public RequestIdViewComponent(RequestIdService requestIdService)
-        public RequestIdService RequestIdService { get; set; }
+        {
+            RequestIdService = requestIdService;
+        }
+
+        private RequestIdService RequestIdService { get; }
 
         public IViewComponentResult Invoke()
         {