Construction injection

src/Components/Authorization/test/AuthorizeRouteViewTest.cs

@@ -35,7 +35,7 @@ public AuthorizeRouteViewTest()
 
         var services = serviceCollection.BuildServiceProvider();
         _renderer = new TestRenderer(services);
-        var componentFactory = new ComponentFactory(new DefaultComponentActivator(), _renderer);
+        var componentFactory = new ComponentFactory(new DefaultComponentActivator(services), _renderer);
         _authorizeRouteViewComponent = (AuthorizeRouteView)componentFactory.InstantiateComponent(services, typeof(AuthorizeRouteView), null, null);
         _authorizeRouteViewComponentId = _renderer.AssignRootComponentId(_authorizeRouteViewComponent);
     }

src/Components/Components/src/ComponentFactory.cs

@@ -90,9 +90,9 @@ public IComponent InstantiateComponent(IServiceProvider serviceProvider, [Dynami
     private static void PerformPropertyInjection(IServiceProvider serviceProvider, IComponent instance)
     {
         // Suppressed with "pragma warning disable" so ILLink Roslyn Anayzer doesn't report the warning.
-        #pragma warning disable IL2072 // 'componentType' argument does not satisfy 'DynamicallyAccessedMemberTypes.All' in call to 'Microsoft.AspNetCore.Components.ComponentFactory.GetComponentTypeInfo(Type)'.
+#pragma warning disable IL2072 // 'componentType' argument does not satisfy 'DynamicallyAccessedMemberTypes.All' in call to 'Microsoft.AspNetCore.Components.ComponentFactory.GetComponentTypeInfo(Type)'.
         var componentTypeInfo = GetComponentTypeInfo(instance.GetType());
-        #pragma warning restore IL2072 // 'componentType' argument does not satisfy 'DynamicallyAccessedMemberTypes.All' in call to 'Microsoft.AspNetCore.Components.ComponentFactory.GetComponentTypeInfo(Type)'.
+#pragma warning restore IL2072 // 'componentType' argument does not satisfy 'DynamicallyAccessedMemberTypes.All' in call to 'Microsoft.AspNetCore.Components.ComponentFactory.GetComponentTypeInfo(Type)'.
 
         componentTypeInfo.PerformPropertyInjection(serviceProvider, instance);
     }

src/Components/Components/src/DefaultComponentActivator.cs

@@ -1,13 +1,17 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Collections.Concurrent;
 using System.Diagnostics.CodeAnalysis;
+using Microsoft.Extensions.DependencyInjection;
 
 namespace Microsoft.AspNetCore.Components;
 
-internal sealed class DefaultComponentActivator : IComponentActivator
+internal sealed class DefaultComponentActivator(IServiceProvider serviceProvider) : IComponentActivator
 {
-    public static IComponentActivator Instance { get; } = new DefaultComponentActivator();
+    private static readonly ConcurrentDictionary<Type, ObjectFactory> _cachedComponentTypeInfo = new();
+
+    public static void ClearCache() => _cachedComponentTypeInfo.Clear();
 
     /// <inheritdoc />
     public IComponent CreateInstance([DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicConstructors)] Type componentType)
@@ -17,6 +21,22 @@ public IComponent CreateInstance([DynamicallyAccessedMembers(DynamicallyAccessed
             throw new ArgumentException($"The type {componentType.FullName} does not implement {nameof(IComponent)}.", nameof(componentType));
         }
 
-        return (IComponent)Activator.CreateInstance(componentType)!;
+        var factory = GetObjectFactory(componentType);
+
+        return (IComponent)factory(serviceProvider, []);
+    }
+
+    private static ObjectFactory GetObjectFactory([DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicConstructors)] Type componentType)
+    {
+        // Unfortunately we can't use 'GetOrAdd' here because the DynamicallyAccessedMembers annotation doesn't flow through to the
+        // callback, so it becomes an IL2111 warning. The following is equivalent and thread-safe because it's a ConcurrentDictionary
+        // and it doesn't matter if we build a cache entry more than once.
+        if (!_cachedComponentTypeInfo.TryGetValue(componentType, out var factory))
+        {
+            factory = ActivatorUtilities.CreateFactory(componentType, Type.EmptyTypes);
+            _cachedComponentTypeInfo.TryAdd(componentType, factory);
+        }
+
+        return factory;
     }
 }

src/Components/Components/src/RenderTree/Renderer.cs

@@ -102,7 +102,7 @@ public Renderer(IServiceProvider serviceProvider, ILoggerFactory loggerFactory,
     private static IComponentActivator GetComponentActivatorOrDefault(IServiceProvider serviceProvider)
     {
         return serviceProvider.GetService<IComponentActivator>()
-            ?? DefaultComponentActivator.Instance;
+            ?? new DefaultComponentActivator(serviceProvider);
     }
 
     /// <summary>
@@ -155,6 +155,7 @@ private async void RenderRootComponentsOnHotReload()
         // Before re-rendering the root component, also clear any well-known caches in the framework
         ComponentFactory.ClearCache();
         ComponentProperties.ClearCache();
+        DefaultComponentActivator.ClearCache();
 
         await Dispatcher.InvokeAsync(() =>
         {

src/Components/Components/test/ComponentFactoryTest.cs

@@ -15,8 +15,9 @@ public void InstantiateComponent_CreatesInstance()
     {
         // Arrange
         var componentType = typeof(EmptyComponent);
-        var factory = new ComponentFactory(new DefaultComponentActivator(), new TestRenderer());
-
+        var serviceProvider = GetServiceProvider();
+        var factory = new ComponentFactory(new DefaultComponentActivator(serviceProvider), new TestRenderer());
+
         // Act
         var instance = factory.InstantiateComponent(GetServiceProvider(), componentType, null, null);
 
@@ -30,8 +31,9 @@ public void InstantiateComponent_CreatesInstance_NonComponent()
     {
         // Arrange
         var componentType = typeof(List<string>);
-        var factory = new ComponentFactory(new DefaultComponentActivator(), new TestRenderer());
-
+        var serviceProvider = GetServiceProvider();
+        var factory = new ComponentFactory(new DefaultComponentActivator(serviceProvider), new TestRenderer());
+
         // Assert
         var ex = Assert.Throws<ArgumentException>(() => factory.InstantiateComponent(GetServiceProvider(), componentType, null, null));
         Assert.StartsWith($"The type {componentType.FullName} does not implement {nameof(IComponent)}.", ex.Message);
@@ -99,10 +101,11 @@ public void InstantiateComponent_IgnoresPropertiesWithoutInjectAttribute()
     {
         // Arrange
         var componentType = typeof(ComponentWithNonInjectableProperties);
-        var factory = new ComponentFactory(new DefaultComponentActivator(), new TestRenderer());
+        var serviceProvider = GetServiceProvider();
+        var factory = new ComponentFactory(new DefaultComponentActivator(serviceProvider), new TestRenderer());
 
         // Act
-        var instance = factory.InstantiateComponent(GetServiceProvider(), componentType, null, null);
+        var instance = factory.InstantiateComponent(serviceProvider, componentType, null, null);
 
         // Assert
         Assert.NotNull(instance);
@@ -119,10 +122,11 @@ public void InstantiateComponent_WithNoRenderMode_DoesNotUseRenderModeResolver()
         var componentType = typeof(ComponentWithInjectProperties);
         var renderer = new RendererWithResolveComponentForRenderMode(
             /* won't be used */ new ComponentWithRenderMode());
-        var factory = new ComponentFactory(new DefaultComponentActivator(), renderer);
+        var serviceProvider = GetServiceProvider();
+        var factory = new ComponentFactory(new DefaultComponentActivator(serviceProvider), renderer);
 
         // Act
-        var instance = factory.InstantiateComponent(GetServiceProvider(), componentType, null, null);
+        var instance = factory.InstantiateComponent(serviceProvider, componentType, null, null);
 
         // Assert
         Assert.IsType<ComponentWithInjectProperties>(instance);
@@ -136,11 +140,12 @@ public void InstantiateComponent_WithRenderModeOnComponent_UsesRenderModeResolve
         var resolvedComponent = new ComponentWithInjectProperties();
         var componentType = typeof(ComponentWithRenderMode);
         var renderer = new RendererWithResolveComponentForRenderMode(resolvedComponent);
-        var componentActivator = new DefaultComponentActivator();
+        var serviceProvider = GetServiceProvider();
+        var componentActivator = new DefaultComponentActivator(serviceProvider);
         var factory = new ComponentFactory(componentActivator, renderer);
 
         // Act
-        var instance = (ComponentWithInjectProperties)factory.InstantiateComponent(GetServiceProvider(), componentType, null, 1234);
+        var instance = (ComponentWithInjectProperties)factory.InstantiateComponent(serviceProvider, componentType, null, 1234);
 
         // Assert
         Assert.True(renderer.ResolverWasCalled);
@@ -167,12 +172,13 @@ public void InstantiateComponent_WithDerivedRenderModeOnDerivedComponent_CausesA
         var resolvedComponent = new ComponentWithInjectProperties();
         var componentType = typeof(DerivedComponentWithRenderMode);
         var renderer = new RendererWithResolveComponentForRenderMode(resolvedComponent);
-        var componentActivator = new DefaultComponentActivator();
+        var serviceProvider = GetServiceProvider();
+        var componentActivator = new DefaultComponentActivator(serviceProvider);
         var factory = new ComponentFactory(componentActivator, renderer);
 
         // Act/Assert
         Assert.Throws<AmbiguousMatchException>(
-            () => factory.InstantiateComponent(GetServiceProvider(), componentType, null, 1234));
+            () => factory.InstantiateComponent(serviceProvider, componentType, null, 1234));
     }
 
     [Fact]
@@ -185,11 +191,12 @@ public void InstantiateComponent_WithRenderModeOnCallSite_UsesRenderModeResolver
         var componentType = typeof(ComponentWithNonInjectableProperties);
         var callSiteRenderMode = new TestRenderMode();
         var renderer = new RendererWithResolveComponentForRenderMode(resolvedComponent);
-        var componentActivator = new DefaultComponentActivator();
+        var serviceProvider = GetServiceProvider();
+        var componentActivator = new DefaultComponentActivator(serviceProvider);
         var factory = new ComponentFactory(componentActivator, renderer);
 
         // Act
-        var instance = (ComponentWithInjectProperties)factory.InstantiateComponent(GetServiceProvider(), componentType, callSiteRenderMode, 1234);
+        var instance = (ComponentWithInjectProperties)factory.InstantiateComponent(serviceProvider, componentType, callSiteRenderMode, 1234);
 
         // Assert
         Assert.Same(resolvedComponent, instance);
@@ -207,7 +214,8 @@ public void InstantiateComponent_WithRenderModeOnComponentAndCallSite_Throws()
         var resolvedComponent = new ComponentWithInjectProperties();
         var componentType = typeof(ComponentWithRenderMode);
         var renderer = new RendererWithResolveComponentForRenderMode(resolvedComponent);
-        var componentActivator = new DefaultComponentActivator();
+        var serviceProvider = GetServiceProvider();
+        var componentActivator = new DefaultComponentActivator(serviceProvider);
         var factory = new ComponentFactory(componentActivator, renderer);
 
         // Even though the two rendermodes are literally the same object, we don't allow specifying any nonnull
@@ -220,6 +228,28 @@ public void InstantiateComponent_WithRenderModeOnComponentAndCallSite_Throws()
         Assert.Equal($"The component type '{componentType}' has a fixed rendermode of '{typeof(TestRenderMode)}', so it is not valid to specify any rendermode when using this component.", ex.Message);
     }
 
+    [Fact]
+    public void InstantiateComponent_CreatesInstance_WithTypeActivation()
+    {
+        // Arrange
+        var serviceProvider = GetServiceProvider();
+        var componentType = typeof(ComponentWithConstructorInjection);
+        var resolvedComponent = new ComponentWithInjectProperties();
+        var renderer = new RendererWithResolveComponentForRenderMode(resolvedComponent);
+        var defaultComponentActivator = new DefaultComponentActivator(serviceProvider);
+        var factory = new ComponentFactory(defaultComponentActivator, renderer);
+
+        // Act
+        var instance = factory.InstantiateComponent(serviceProvider, componentType, null, null);
+
+        // Assert
+        Assert.NotNull(instance);
+        var component = Assert.IsType<ComponentWithConstructorInjection>(instance);
+        Assert.NotNull(component.Property1);
+        Assert.NotNull(component.Property2);
+        Assert.NotNull(component.Property3); // Property injection should still work.
+    }
+
     private const string KeyedServiceKey = "my-keyed-service";
 
     private static IServiceProvider GetServiceProvider()
@@ -292,6 +322,31 @@ public Task SetParametersAsync(ParameterView parameters)
         }
     }
 
+    public class ComponentWithConstructorInjection : IComponent
+    {
+        public ComponentWithConstructorInjection(TestService1 property1, TestService2 property2)
+        {
+            Property1 = property1;
+            Property2 = property2;
+        }
+
+        public TestService1 Property1 { get; }
+        public TestService2 Property2 { get; }
+
+        [Inject]
+        public TestService2 Property3 { get; set; }
+
+        public void Attach(RenderHandle renderHandle)
+        {
+            throw new NotImplementedException();
+        }
+
+        public Task SetParametersAsync(ParameterView parameters)
+        {
+            throw new NotImplementedException();
+        }
+    }
+
     private class DerivedComponent : ComponentWithInjectProperties
     {
         public new TestService2 Property4 { get; set; }

src/Components/Components/test/RouteViewTest.cs

@@ -23,7 +23,7 @@ public RouteViewTest()
         var services = serviceCollection.BuildServiceProvider();
         _renderer = new TestRenderer(services);
 
-        var componentFactory = new ComponentFactory(new DefaultComponentActivator(), _renderer);
+        var componentFactory = new ComponentFactory(new DefaultComponentActivator(services), _renderer);
         _routeViewComponent = (RouteView)componentFactory.InstantiateComponent(services, typeof(RouteView), null, null);
 
         _routeViewComponentId = _renderer.AssignRootComponentId(_routeViewComponent);