[Fixes #3752] Refactor and cleanup view components

* Moved instantiation of view components into DefaultViewComponentActivator
* Introduced IViewComponentFactory to handling setup of new view component instances.
* Added a release method on IViewComponentActivator for handling tear down of view
  component instances.

src/Microsoft.AspNetCore.Mvc.ViewFeatures/DependencyInjection/MvcViewFeaturesMvcCoreBuilderExtensions.cs

@@ -118,8 +118,10 @@ namespace Microsoft.Extensions.DependencyInjection
             //
             // View Components
             //
+            
             // These do caching so they should stay singleton
             services.TryAddSingleton<IViewComponentSelector, DefaultViewComponentSelector>();
+            services.TryAddSingleton<IViewComponentFactory, DefaultViewComponentFactory>();
             services.TryAddSingleton<IViewComponentActivator, DefaultViewComponentActivator>();
             services.TryAddSingleton<
                 IViewComponentDescriptorCollectionProvider,

src/Microsoft.AspNetCore.Mvc.ViewFeatures/Properties/Resources.Designer.cs

@@ -858,6 +858,22 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures
             return string.Format(CultureInfo.CurrentCulture, GetString("ViewComponent_AmbiguousMethods"), p0, p1, p2);
         }
 
+        /// <summary>
+        /// The type '{0}' cannot be activated by '{1}' because it is either a value type, an interface, an abstract class or an open generic type.
+        /// </summary>
+        internal static string ValueInterfaceAbstractOrOpenGenericTypesCannotBeActivated
+        {
+            get { return GetString("ValueInterfaceAbstractOrOpenGenericTypesCannotBeActivated"); }
+        }
+
+        /// <summary>
+        /// The type '{0}' cannot be activated by '{1}' because it is either a value type, an interface, an abstract class or an open generic type.
+        /// </summary>
+        internal static string FormatValueInterfaceAbstractOrOpenGenericTypesCannotBeActivated(object p0, object p1)
+        {
+            return string.Format(CultureInfo.CurrentCulture, GetString("ValueInterfaceAbstractOrOpenGenericTypesCannotBeActivated"), p0, p1);
+        }
+
         private static string GetString(string name, params string[] formatterNames)
         {
             var value = _resourceManager.GetString(name);

src/Microsoft.AspNetCore.Mvc.ViewFeatures/Resources.resx

@@ -277,4 +277,7 @@
   <data name="ViewComponent_AmbiguousMethods" xml:space="preserve">
     <value>View component '{0}' must have exactly one public method named '{1}' or '{2}'.</value>
   </data>
+  <data name="ValueInterfaceAbstractOrOpenGenericTypesCannotBeActivated" xml:space="preserve">
+    <value>The type '{0}' cannot be activated by '{1}' because it is either a value type, an interface, an abstract class or an open generic type.</value>
+  </data>
 </root>

src/Microsoft.AspNetCore.Mvc.ViewFeatures/ViewComponents/DefaultViewComponentActivator.cs

@@ -2,9 +2,9 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.Collections.Concurrent;
 using System.Reflection;
-using Microsoft.Extensions.Internal;
+using Microsoft.AspNetCore.Mvc.Internal;
+using Microsoft.AspNetCore.Mvc.ViewFeatures;
 
 namespace Microsoft.AspNetCore.Mvc.ViewComponents
 {
@@ -18,49 +18,71 @@ namespace Microsoft.AspNetCore.Mvc.ViewComponents
     /// </remarks>
     public class DefaultViewComponentActivator : IViewComponentActivator
     {
-        private readonly Func<Type, PropertyActivator<ViewComponentContext>[]> _getPropertiesToActivate;
-        private readonly ConcurrentDictionary<Type, PropertyActivator<ViewComponentContext>[]> _injectActions;
+        private readonly ITypeActivatorCache _typeActivatorCache;
 
         /// <summary>
         /// Initializes a new instance of <see cref="DefaultViewComponentActivator"/> class.
         /// </summary>
-        public DefaultViewComponentActivator()
+        /// <param name="typeActivatorCache">
+        /// The <see cref="ITypeActivatorCache"/> used to create new view component instances.
+        /// </param>
+        public DefaultViewComponentActivator(ITypeActivatorCache typeActivatorCache)
         {
-            _injectActions = new ConcurrentDictionary<Type, PropertyActivator<ViewComponentContext>[]>();
-            _getPropertiesToActivate = type =>
-                PropertyActivator<ViewComponentContext>.GetPropertiesToActivate(
-                    type,
-                    typeof(ViewComponentContextAttribute),
-                    CreateActivateInfo);
+            if (typeActivatorCache == null)
+            {
+                throw new ArgumentNullException(nameof(typeActivatorCache));
+            }
+
+            _typeActivatorCache = typeActivatorCache;
         }
 
         /// <inheritdoc />
-        public virtual void Activate(object viewComponent, ViewComponentContext context)
+        public virtual object Create(ViewComponentContext context)
         {
-            if (viewComponent == null)
-            {
-                throw new ArgumentNullException(nameof(viewComponent));
-            }
-
             if (context == null)
             {
                 throw new ArgumentNullException(nameof(context));
             }
 
-            var propertiesToActivate = _injectActions.GetOrAdd(
-                viewComponent.GetType(),
-                _getPropertiesToActivate);
+            var componentType = context.ViewComponentDescriptor.Type.GetTypeInfo();
 
-            for (var i = 0; i < propertiesToActivate.Length; i++)
+            if (componentType.IsValueType ||
+                componentType.IsInterface ||
+                componentType.IsAbstract ||
+                (componentType.IsGenericType && componentType.IsGenericTypeDefinition))
             {
-                var activateInfo = propertiesToActivate[i];
-                activateInfo.Activate(viewComponent, context);
+                var message = Resources.FormatValueInterfaceAbstractOrOpenGenericTypesCannotBeActivated(
+                    componentType.FullName,
+                    GetType().FullName);
+
+                throw new InvalidOperationException(message);
             }
+
+            var viewComponent = _typeActivatorCache.CreateInstance<object>(
+                context.ViewContext.HttpContext.RequestServices,
+                context.ViewComponentDescriptor.Type);
+
+            return viewComponent;
         }
 
-        private PropertyActivator<ViewComponentContext> CreateActivateInfo(PropertyInfo property)
+        /// <inheritdoc />
+        public virtual void Release(ViewComponentContext context, object viewComponent)
         {
-            return new PropertyActivator<ViewComponentContext>(property, context => context);
+            if (context == null)
+            {
+                throw new InvalidOperationException(nameof(context));
+            }
+
+            if (viewComponent == null)
+            {
+                throw new InvalidOperationException(nameof(viewComponent));
+            }
+
+            var disposable = viewComponent as IDisposable;
+            if (disposable != null)
+            {
+                disposable.Dispose();
+            }
         }
     }
 }

src/Microsoft.AspNetCore.Mvc.ViewFeatures/ViewComponents/DefaultViewComponentFactory.cs

@@ -0,0 +1,96 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Concurrent;
+using System.Reflection;
+using Microsoft.Extensions.Internal;
+
+namespace Microsoft.AspNetCore.Mvc.ViewComponents
+{
+    /// <summary>
+    /// Default implementation for <see cref="IViewComponentFactory"/>.
+    /// </summary>
+    public class DefaultViewComponentFactory : IViewComponentFactory
+    {
+        private readonly IViewComponentActivator _activator;
+        private readonly Func<Type, PropertyActivator<ViewComponentContext>[]> _getPropertiesToActivate;
+        private readonly ConcurrentDictionary<Type, PropertyActivator<ViewComponentContext>[]> _injectActions;
+
+        /// <summary>
+        /// Creates a new instance of <see cref="DefaultViewComponentFactory"/>
+        /// </summary>
+        /// <param name="activator">
+        /// The <see cref="IViewComponentActivator"/> used to create new view component instances.
+        /// </param>
+        public DefaultViewComponentFactory(IViewComponentActivator activator)
+        {
+            if (activator == null)
+            {
+                throw new ArgumentNullException(nameof(activator));
+            }
+
+            _activator = activator;
+
+            _getPropertiesToActivate = type => PropertyActivator<ViewComponentContext>.GetPropertiesToActivate(
+                type,
+                typeof(ViewComponentContextAttribute),
+                CreateActivateInfo);
+
+            _injectActions = new ConcurrentDictionary<Type, PropertyActivator<ViewComponentContext>[]>();
+        }
+
+        /// <inheritdoc />
+        public object CreateViewComponent(ViewComponentContext context)
+        {
+            if (context == null)
+            {
+                throw new ArgumentNullException(nameof(context));
+            }
+
+            var component = _activator.Create(context);
+
+            InjectProperties(context, component);
+
+            return component;
+        }
+
+        private void InjectProperties(ViewComponentContext context, object viewComponent)
+        {
+            var propertiesToActivate = _injectActions.GetOrAdd(
+                viewComponent.GetType(),
+                type =>
+                PropertyActivator<ViewComponentContext>.GetPropertiesToActivate(
+                    type,
+                    typeof(ViewComponentContextAttribute),
+                    CreateActivateInfo));
+
+            for (var i = 0; i < propertiesToActivate.Length; i++)
+            {
+                var activateInfo = propertiesToActivate[i];
+                activateInfo.Activate(viewComponent, context);
+            }
+        }
+
+        private static PropertyActivator<ViewComponentContext> CreateActivateInfo(PropertyInfo property)
+        {
+            return new PropertyActivator<ViewComponentContext>(property, context => context);
+        }
+
+        /// <inheritdoc />
+        public void ReleaseViewComponent(ViewComponentContext context, object component)
+        {
+            if (context == null)
+            {
+                throw new ArgumentNullException(nameof(context));
+            }
+
+            if (component == null)
+            {
+                throw new ArgumentNullException(nameof(component));
+            }
+
+            _activator.Release(context, component);
+        }
+    }
+}

src/Microsoft.AspNetCore.Mvc.ViewFeatures/ViewComponents/DefaultViewComponentInvoker.cs

@@ -19,8 +19,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewComponents
     /// </summary>
     public class DefaultViewComponentInvoker : IViewComponentInvoker
     {
-        private readonly ITypeActivatorCache _typeActivatorCache;
-        private readonly IViewComponentActivator _viewComponentActivator;
+        private readonly IViewComponentFactory _viewComponentFactory;
         private readonly DiagnosticSource _diagnosticSource;
         private readonly ILogger _logger;
 
@@ -28,23 +27,17 @@ namespace Microsoft.AspNetCore.Mvc.ViewComponents
         /// Initializes a new instance of <see cref="DefaultViewComponentInvoker"/>.
         /// </summary>
         /// <param name="typeActivatorCache">Caches factories for instantiating view component instances.</param>
-        /// <param name="viewComponentActivator">The <see cref="IViewComponentActivator"/>.</param>
+        /// <param name="viewComponentFactory">The <see cref="IViewComponentFactory"/>.</param>
         /// <param name="diagnosticSource">The <see cref="DiagnosticSource"/>.</param>
         /// <param name="logger">The <see cref="ILogger"/>.</param>
         public DefaultViewComponentInvoker(
-            ITypeActivatorCache typeActivatorCache,
-            IViewComponentActivator viewComponentActivator,
+            IViewComponentFactory viewComponentFactory,
             DiagnosticSource diagnosticSource,
             ILogger logger)
         {
-            if (typeActivatorCache == null)
+            if (viewComponentFactory == null)
             {
-                throw new ArgumentNullException(nameof(typeActivatorCache));
-            }
-
-            if (viewComponentActivator == null)
-            {
-                throw new ArgumentNullException(nameof(viewComponentActivator));
+                throw new ArgumentNullException(nameof(viewComponentFactory));
             }
 
             if (diagnosticSource == null)
@@ -57,8 +50,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewComponents
                 throw new ArgumentNullException(nameof(logger));
             }
 
-            _typeActivatorCache = typeActivatorCache;
-            _viewComponentActivator = viewComponentActivator;
+            _viewComponentFactory = viewComponentFactory;
             _diagnosticSource = diagnosticSource;
             _logger = logger;
         }
@@ -95,24 +87,9 @@ namespace Microsoft.AspNetCore.Mvc.ViewComponents
             await result.ExecuteAsync(context);
         }
 
-        private object CreateComponent(ViewComponentContext context)
-        {
-            if (context == null)
-            {
-                throw new ArgumentNullException(nameof(context));
-            }
-
-            var services = context.ViewContext.HttpContext.RequestServices;
-            var component = _typeActivatorCache.CreateInstance<object>(
-                services,
-                context.ViewComponentDescriptor.Type);
-            _viewComponentActivator.Activate(component, context);
-            return component;
-        }
-
         private async Task<IViewComponentResult> InvokeAsyncCore(ViewComponentContext context)
         {
-            var component = CreateComponent(context);
+            var component = _viewComponentFactory.CreateViewComponent(context);
 
             using (_logger.ViewComponentScope(context))
             {
@@ -129,13 +106,15 @@ namespace Microsoft.AspNetCore.Mvc.ViewComponents
                 _logger.ViewComponentExecuted(context, startTimestamp, viewComponentResult);
                 _diagnosticSource.AfterViewComponent(context, viewComponentResult, component);
 
+                _viewComponentFactory.ReleaseViewComponent(context, component);
+
                 return viewComponentResult;
             }
         }
 
         private IViewComponentResult InvokeSyncCore(ViewComponentContext context)
         {
-            var component = CreateComponent(context);
+            var component = _viewComponentFactory.CreateViewComponent(context);
 
             using (_logger.ViewComponentScope(context))
             {
@@ -155,6 +134,8 @@ namespace Microsoft.AspNetCore.Mvc.ViewComponents
                 }
                 catch (TargetInvocationException ex)
                 {
+                    _viewComponentFactory.ReleaseViewComponent(context, component);
+
                     // Preserve callstack of any user-thrown exceptions.
                     var exceptionInfo = ExceptionDispatchInfo.Capture(ex.InnerException);
                     exceptionInfo.Throw();
@@ -165,6 +146,8 @@ namespace Microsoft.AspNetCore.Mvc.ViewComponents
                 _logger.ViewComponentExecuted(context, startTimestamp, viewComponentResult);
                 _diagnosticSource.AfterViewComponent(context, viewComponentResult, component);
 
+                _viewComponentFactory.ReleaseViewComponent(context, component);
+
                 return viewComponentResult;
             }
         }

src/Microsoft.AspNetCore.Mvc.ViewFeatures/ViewComponents/DefaultViewComponentInvokerFactory.cs

@@ -10,19 +10,31 @@ namespace Microsoft.AspNetCore.Mvc.ViewComponents
 {
     public class DefaultViewComponentInvokerFactory : IViewComponentInvokerFactory
     {
-        private readonly ITypeActivatorCache _typeActivatorCache;
-        private readonly IViewComponentActivator _viewComponentActivator;
+        private readonly IViewComponentFactory _viewComponentFactory;
         private readonly ILogger _logger;
         private readonly DiagnosticSource _diagnosticSource;
 
         public DefaultViewComponentInvokerFactory(
-            ITypeActivatorCache typeActivatorCache,
-            IViewComponentActivator viewComponentActivator,
+            IViewComponentFactory viewComponentFactory,
             DiagnosticSource diagnosticSource,
             ILoggerFactory loggerFactory)
         {
-            _typeActivatorCache = typeActivatorCache;
-            _viewComponentActivator = viewComponentActivator;
+            if (viewComponentFactory == null)
+            {
+                throw new ArgumentNullException(nameof(viewComponentFactory));
+            }
+
+            if (diagnosticSource == null)
+            {
+                throw new ArgumentNullException(nameof(diagnosticSource));
+            }
+
+            if (loggerFactory == null)
+            {
+                throw new ArgumentNullException(nameof(loggerFactory));
+            }
+
+            _viewComponentFactory = viewComponentFactory;
             _diagnosticSource = diagnosticSource;
 
             _logger = loggerFactory.CreateLogger<DefaultViewComponentInvoker>();
@@ -40,8 +52,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewComponents
             }
 
             return new DefaultViewComponentInvoker(
-                _typeActivatorCache,
-                _viewComponentActivator,
+                _viewComponentFactory,
                 _diagnosticSource,
                 _logger);
         }

src/Microsoft.AspNetCore.Mvc.ViewFeatures/ViewComponents/IViewComponentActivator.cs

@@ -4,17 +4,25 @@
 namespace Microsoft.AspNetCore.Mvc.ViewComponents
 {
     /// <summary>
-    /// Provides methods to activate an instantiated ViewComponent
+    /// Provides methods to instantiate and release a ViewComponent.
     /// </summary>
     public interface IViewComponentActivator
     {
         /// <summary>
-        /// When implemented in a type, activates an instantiated ViewComponent.
+        /// Instantiates a ViewComponent.
         /// </summary>
-        /// <param name="viewComponent">The ViewComponent to activate.</param>
         /// <param name="context">
         /// The <see cref="ViewComponentContext"/> for the executing <see cref="ViewComponent"/>.
         /// </param>
-        void Activate(object viewComponent, ViewComponentContext context);
+        object Create(ViewComponentContext context);
+
+        /// <summary>
+        /// Releases a ViewComponent instance.
+        /// </summary>
+        /// <param name="context">
+        /// The <see cref="ViewComponentContext"/> associated with the <paramref name="component"/>.
+        /// </param>
+        /// <param name="viewComponent">The <see cref="ViewComponent"/> to release.</param>
+        void Release(ViewComponentContext context, object viewComponent);
     }
 }

src/Microsoft.AspNetCore.Mvc.ViewFeatures/ViewComponents/IViewComponentFactory.cs

@@ -0,0 +1,25 @@
+// 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.
+
+namespace Microsoft.AspNetCore.Mvc.ViewComponents
+{
+    /// <summary>
+    /// Provides methods for creation and disposal of view components.
+    /// </summary>
+    public interface IViewComponentFactory
+    {
+        /// <summary>
+        /// Creates a new controller for the specified <paramref name="context"/>.
+        /// </summary>
+        /// <param name="context"><see cref="ViewComponentContext"/> for the view component.</param>
+        /// <returns>The view component.</returns>
+        object CreateViewComponent(ViewComponentContext context);
+
+        /// <summary>
+        /// Releases a view component instance.
+        /// </summary>
+        /// <param name="context">The context associated with the <paramref name="component"/>.</param>
+        /// <param name="component">The view component.</param>
+        void ReleaseViewComponent(ViewComponentContext context, object component);
+    }
+}

test/Microsoft.AspNetCore.Mvc.ViewFeatures.Test/ViewComponentResultTest.cs

@@ -525,6 +525,7 @@ namespace Microsoft.AspNetCore.Mvc
             services.AddSingleton<IViewComponentInvokerFactory, DefaultViewComponentInvokerFactory>();
             services.AddSingleton<ITypeActivatorCache, TypeActivatorCache>();
             services.AddSingleton<IViewComponentActivator, DefaultViewComponentActivator>();
+            services.AddSingleton<IViewComponentFactory, DefaultViewComponentFactory>();
             services.AddSingleton<IViewComponentDescriptorProvider>(new FixedSetViewComponentDescriptorProvider(descriptors));
             services.AddSingleton<IModelMetadataProvider, EmptyModelMetadataProvider>();
             services.AddSingleton<ILoggerFactory>(NullLoggerFactory.Instance);
@@ -573,6 +574,16 @@ namespace Microsoft.AspNetCore.Mvc
             }
         }
 
+        private static string ReadBody(HttpResponse response)
+        {
+            response.Body.Seek(0, SeekOrigin.Begin);
+
+            using (var reader = new StreamReader(response.Body))
+            {
+                return reader.ReadToEnd();
+            }
+        }
+
         private class TextViewComponent : ViewComponent
         {
             public HtmlString Invoke(string name)
@@ -588,15 +599,5 @@ namespace Microsoft.AspNetCore.Mvc
                 return Task.FromResult(new HtmlString("Hello-Async, " + name));
             }
         }
-
-        private static string ReadBody(HttpResponse response)
-        {
-            response.Body.Seek(0, SeekOrigin.Begin);
-
-            using (var reader = new StreamReader(response.Body))
-            {
-                return reader.ReadToEnd();
-            }
-        }
     }
 }

test/Microsoft.AspNetCore.Mvc.ViewFeatures.Test/ViewComponents/DefaultViewComponentActivatorTests.cs

@@ -3,6 +3,10 @@
 
 using System;
 using System.Threading.Tasks;
+using Microsoft.AspNetCore.Http.Internal;
+using Microsoft.AspNetCore.Mvc.Internal;
+using Microsoft.AspNetCore.Mvc.Rendering;
+using Moq;
 using Xunit;
 
 namespace Microsoft.AspNetCore.Mvc.ViewComponents
@@ -13,35 +17,116 @@ namespace Microsoft.AspNetCore.Mvc.ViewComponents
         public void DefaultViewComponentActivator_ActivatesViewComponentContext()
         {
             // Arrange
-            var activator = new DefaultViewComponentActivator();
+            var expectedInstance = new TestViewComponent();
 
-            var context = new ViewComponentContext();
-            var instance = new TestViewComponent();
+            var typeActivator = new Mock<ITypeActivatorCache>();
+            typeActivator
+                .Setup(ta => ta.CreateInstance<object>(It.IsAny<IServiceProvider>(), It.IsAny<Type>()))
+                .Returns(expectedInstance);
+
+            var activator = new DefaultViewComponentActivator(typeActivator.Object);
+
+            var context = CreateContext(typeof(TestViewComponent));
+            expectedInstance.ViewComponentContext = context;
 
             // Act
-            activator.Activate(instance, context);
+            var instance = activator.Create(context) as ViewComponent;
 
             // Assert
+            Assert.NotNull(instance);
             Assert.Same(context, instance.ViewComponentContext);
         }
 
+        [Theory]
+        [InlineData(typeof(int))]
+        [InlineData(typeof(OpenGenericType<>))]
+        [InlineData(typeof(AbstractType))]
+        [InlineData(typeof(InterfaceType))]
+        public void Create_ThrowsIfControllerCannotBeActivated(Type type)
+        {
+            // Arrange
+            var actionDescriptor = new ViewComponentDescriptor
+            {
+                Type = type
+            };
+
+            var context = new ViewComponentContext
+            {
+                ViewComponentDescriptor = actionDescriptor,
+                ViewContext = new ViewContext
+                {
+                    HttpContext = new DefaultHttpContext()
+                    {
+                        RequestServices = Mock.Of<IServiceProvider>()
+                    },
+                }
+            };
+
+            var activator = new DefaultViewComponentActivator(new TypeActivatorCache());
+
+            // Act and Assert
+            var exception = Assert.Throws<InvalidOperationException>(() => activator.Create(context));
+            Assert.Equal(
+                $"The type '{type.FullName}' cannot be activated by '{typeof(DefaultViewComponentActivator).FullName}' " +
+                "because it is either a value type, an interface, an abstract class or an open generic type.",
+                exception.Message);
+        }
+
         [Fact]
         public void DefaultViewComponentActivator_ActivatesViewComponentContext_IgnoresNonPublic()
         {
             // Arrange
-            var activator = new DefaultViewComponentActivator();
+            var expectedInstance = new VisibilityViewComponent();
 
-            var context = new ViewComponentContext();
-            var instance = new VisibilityViewComponent();
+            var typeActivator = new Mock<ITypeActivatorCache>();
+            typeActivator
+                .Setup(ta => ta.CreateInstance<object>(It.IsAny<IServiceProvider>(), It.IsAny<Type>()))
+                .Returns(expectedInstance);
+
+            var activator = new DefaultViewComponentActivator(typeActivator.Object);
+
+            var context = CreateContext(typeof(VisibilityViewComponent));
+            expectedInstance.ViewComponentContext = context;
 
             // Act
-            activator.Activate(instance, context);
+            var instance = activator.Create(context) as VisibilityViewComponent;
 
             // Assert
+            Assert.NotNull(instance);
             Assert.Same(context, instance.ViewComponentContext);
             Assert.Null(instance.C);
         }
 
+        private static ViewComponentContext CreateContext(Type componentType)
+        {
+            return new ViewComponentContext
+            {
+                ViewComponentDescriptor = new ViewComponentDescriptor
+                {
+                    Type = componentType
+                },
+                ViewContext = new ViewContext
+                {
+                    HttpContext = new DefaultHttpContext
+                    {
+                        RequestServices = Mock.Of<IServiceProvider>()
+                    }
+                }
+            };
+        }
+
+        private class OpenGenericType<T> : Controller
+        {
+        }
+
+        private abstract class AbstractType : Controller
+        {
+        }
+
+        private interface InterfaceType
+        {
+        }
+
         private class TestViewComponent : ViewComponent
         {
             public Task ExecuteAsync()

test/Microsoft.AspNetCore.Mvc.ViewFeatures.Test/ViewComponents/DefaultViewComponentFactoryTest.cs

@@ -0,0 +1,78 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using Moq;
+using Xunit;
+
+namespace Microsoft.AspNetCore.Mvc.ViewComponents
+{
+    public class DefaultViewComponentFactoryTest
+    {
+        [Fact]
+        public void CreateViewComponent_ActivatesProperties_OnTheInstance()
+        {
+            // Arrange
+            var context = new ViewComponentContext
+            {
+            };
+
+            var component = new ActivablePropertiesViewComponent();
+            var activator = new Mock<IViewComponentActivator>();
+            activator.Setup(a => a.Create(context))
+                .Returns(component);
+
+            var factory = new DefaultViewComponentFactory(activator.Object);
+
+            // Act
+            var result = factory.CreateViewComponent(context);
+
+            // Assert
+            var activablePropertiesComponent = Assert.IsType<ActivablePropertiesViewComponent>(result);
+
+            Assert.Same(component, activablePropertiesComponent);
+            Assert.Same(component.Context, activablePropertiesComponent.Context);
+        }
+
+        [Fact]
+        public void ReleaseViewComponent_CallsDispose_OnTheInstance()
+        {
+            // Arrange
+            var context = new ViewComponentContext
+            {
+            };
+
+            var component = new ActivablePropertiesViewComponent();
+
+            var viewComponentActivator = new Mock<IViewComponentActivator>();
+            viewComponentActivator.Setup(vca => vca.Release(context, component))
+                .Callback<ViewComponentContext, object>((c, o) => (o as IDisposable)?.Dispose());
+
+            var factory = new DefaultViewComponentFactory(viewComponentActivator.Object);
+
+            // Act
+            factory.ReleaseViewComponent(context, component);
+
+            // Assert
+            Assert.Equal(true, component.Disposed);
+        }
+    }
+
+    public class ActivablePropertiesViewComponent : IDisposable
+    {
+        [ViewComponentContext]
+        public ViewComponentContext Context { get; set; }
+
+        public bool Disposed { get; private set; }
+
+        public void Dispose()
+        {
+            Disposed = true;
+        }
+
+        public string Invoke()
+        {
+            return "something";
+        }
+    }
+}