Fix tests by supporting TryAddCascadingValue

Author: SteveSandersonMS

src/Components/Components/src/CascadingValueServiceCollectionExtensions.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using Microsoft.AspNetCore.Components;
+using Microsoft.Extensions.DependencyInjection.Extensions;
 
 namespace Microsoft.Extensions.DependencyInjection;
 
@@ -50,4 +51,48 @@ public static IServiceCollection AddCascadingValue<TValue>(
     public static IServiceCollection AddCascadingValue<TValue>(
         this IServiceCollection serviceCollection, Func<IServiceProvider, CascadingValueSource<TValue>> sourceFactory)
         => serviceCollection.AddScoped<ICascadingValueSupplier>(sourceFactory);
+
+    /// <summary>
+    /// Adds a cascading value to the <paramref name="serviceCollection"/>, if none is already registered
+    /// with the value type. This is equivalent to having a fixed <see cref="CascadingValue{TValue}"/> at
+    /// the root of the component hierarchy.
+    /// </summary>
+    /// <typeparam name="TValue">The value type.</typeparam>
+    /// <param name="serviceCollection">The <see cref="IServiceCollection"/>.</param>
+    /// <param name="valueFactory">A callback that supplies a fixed value within each service provider scope.</param>
+    /// <returns>The <see cref="IServiceCollection"/>.</returns>
+    public static void TryAddCascadingValue<TValue>(
+        this IServiceCollection serviceCollection, Func<IServiceProvider, TValue> valueFactory)
+        => serviceCollection.TryAddScoped<ICascadingValueSupplier>(sp => new CascadingValueSource<TValue>(() => valueFactory(sp), isFixed: true));
+
+    /// <summary>
+    /// Adds a cascading value to the <paramref name="serviceCollection"/>, if none is already registered
+    /// with the value type, regardless of the <paramref name="name"/>. This is equivalent to having a fixed
+    /// <see cref="CascadingValue{TValue}"/> at the root of the component hierarchy.
+    /// </summary>
+    /// <typeparam name="TValue">The value type.</typeparam>
+    /// <param name="serviceCollection">The <see cref="IServiceCollection"/>.</param>
+    /// <param name="name">A name for the cascading value. If set, <see cref="CascadingParameterAttribute"/> can be configured to match based on this name.</param>
+    /// <param name="valueFactory">A callback that supplies a fixed value within each service provider scope.</param>
+    /// <returns>The <see cref="IServiceCollection"/>.</returns>
+    public static void TryAddCascadingValue<TValue>(
+        this IServiceCollection serviceCollection, string name, Func<IServiceProvider, TValue> valueFactory)
+        => serviceCollection.TryAddScoped<ICascadingValueSupplier>(sp => new CascadingValueSource<TValue>(name, () => valueFactory(sp), isFixed: true));
+
+    /// <summary>
+    /// Adds a cascading value to the <paramref name="serviceCollection"/>, if none is already registered
+    /// with the value type. This is equivalent to having a fixed <see cref="CascadingValue{TValue}"/> at
+    /// the root of the component hierarchy.
+    /// 
+    /// With this overload, you can supply a <see cref="CascadingValueSource{TValue}"/> which allows you
+    /// to notify about updates to the value later, causing recipients to re-render. This overload should
+    /// only be used if you plan to update the value dynamically.
+    /// </summary>
+    /// <typeparam name="TValue">The value type.</typeparam>
+    /// <param name="serviceCollection">The <see cref="IServiceCollection"/>.</param>
+    /// <param name="sourceFactory">A callback that supplies a <see cref="CascadingValueSource{TValue}"/> within each service provider scope.</param>
+    /// <returns>The <see cref="IServiceCollection"/>.</returns>
+    public static void TryAddCascadingValue<TValue>(
+        this IServiceCollection serviceCollection, Func<IServiceProvider, CascadingValueSource<TValue>> sourceFactory)
+        => serviceCollection.TryAddScoped<ICascadingValueSupplier>(sourceFactory);
 }

src/Components/Components/src/PublicAPI.Unshipped.txt

@@ -91,6 +91,9 @@ static Microsoft.AspNetCore.Components.SupplyParameterFromQueryProviderServiceCo
 static Microsoft.Extensions.DependencyInjection.CascadingValueServiceCollectionExtensions.AddCascadingValue<TValue>(this Microsoft.Extensions.DependencyInjection.IServiceCollection! serviceCollection, string! name, System.Func<System.IServiceProvider!, TValue>! valueFactory) -> Microsoft.Extensions.DependencyInjection.IServiceCollection!
 static Microsoft.Extensions.DependencyInjection.CascadingValueServiceCollectionExtensions.AddCascadingValue<TValue>(this Microsoft.Extensions.DependencyInjection.IServiceCollection! serviceCollection, System.Func<System.IServiceProvider!, Microsoft.AspNetCore.Components.CascadingValueSource<TValue>!>! sourceFactory) -> Microsoft.Extensions.DependencyInjection.IServiceCollection!
 static Microsoft.Extensions.DependencyInjection.CascadingValueServiceCollectionExtensions.AddCascadingValue<TValue>(this Microsoft.Extensions.DependencyInjection.IServiceCollection! serviceCollection, System.Func<System.IServiceProvider!, TValue>! valueFactory) -> Microsoft.Extensions.DependencyInjection.IServiceCollection!
+static Microsoft.Extensions.DependencyInjection.CascadingValueServiceCollectionExtensions.TryAddCascadingValue<TValue>(this Microsoft.Extensions.DependencyInjection.IServiceCollection! serviceCollection, string! name, System.Func<System.IServiceProvider!, TValue>! valueFactory) -> void
+static Microsoft.Extensions.DependencyInjection.CascadingValueServiceCollectionExtensions.TryAddCascadingValue<TValue>(this Microsoft.Extensions.DependencyInjection.IServiceCollection! serviceCollection, System.Func<System.IServiceProvider!, Microsoft.AspNetCore.Components.CascadingValueSource<TValue>!>! sourceFactory) -> void
+static Microsoft.Extensions.DependencyInjection.CascadingValueServiceCollectionExtensions.TryAddCascadingValue<TValue>(this Microsoft.Extensions.DependencyInjection.IServiceCollection! serviceCollection, System.Func<System.IServiceProvider!, TValue>! valueFactory) -> void
 virtual Microsoft.AspNetCore.Components.NavigationManager.Refresh(bool forceReload = false) -> void
 virtual Microsoft.AspNetCore.Components.Rendering.ComponentState.DisposeAsync() -> System.Threading.Tasks.ValueTask
 virtual Microsoft.AspNetCore.Components.RenderTree.Renderer.AddPendingTask(Microsoft.AspNetCore.Components.Rendering.ComponentState? componentState, System.Threading.Tasks.Task! task) -> void

src/Components/Components/test/CascadingParameterTest.cs

@@ -727,6 +727,48 @@ public void OmitsSingleDeliveryCascadingParametersWhenUpdatingDirectParameters()
             });
     }
 
+    [Fact]
+    public void CanUseTryAddPatternForCascadingValuesInServiceCollection_ValueFactory()
+    {
+        // Arrange
+        var services = new ServiceCollection();
+
+        // Act
+        services.TryAddCascadingValue(_ => new SingleDeliveryValue("first"));
+        services.TryAddCascadingValue(_ => new SingleDeliveryValue("second"));
+
+        // Assert
+        Assert.Single(services);
+    }
+
+    [Fact]
+    public void CanUseTryAddPatternForCascadingValuesInServiceCollection_NamedValueFactory()
+    {
+        // Arrange
+        var services = new ServiceCollection();
+
+        // Act
+        services.TryAddCascadingValue("Name1", _ => new SingleDeliveryValue("first"));
+        services.TryAddCascadingValue("Name2", _ => new SingleDeliveryValue("second"));
+
+        // Assert
+        Assert.Single(services);
+    }
+
+    [Fact]
+    public void CanUseTryAddPatternForCascadingValuesInServiceCollection_CascadingValueSource()
+    {
+        // Arrange
+        var services = new ServiceCollection();
+
+        // Act
+        services.TryAddCascadingValue(_ => new CascadingValueSource<SingleDeliveryValue>("Name1", new SingleDeliveryValue("first"), false));
+        services.TryAddCascadingValue(_ => new CascadingValueSource<SingleDeliveryValue>("Name2", new SingleDeliveryValue("second"), false));
+
+        // Assert
+        Assert.Single(services);
+    }
+
     private class SingleDeliveryValue(string text)
     {
         public string Text => text;

src/Components/Endpoints/src/DependencyInjection/RazorComponentsServiceCollectionExtensions.cs

@@ -63,7 +63,7 @@ public static IRazorComponentsBuilder AddRazorComponents(this IServiceCollection
         services.TryAddScoped<EndpointRoutingStateProvider>();
         services.TryAddScoped<IRoutingStateProvider>(sp => sp.GetRequiredService<EndpointRoutingStateProvider>());
         services.AddSupplyValueFromQueryProvider();
-        services.AddCascadingValue(sp => sp.GetRequiredService<EndpointHtmlRenderer>().HttpContext);
+        services.TryAddCascadingValue(sp => sp.GetRequiredService<EndpointHtmlRenderer>().HttpContext);
 
         // Form handling
         services.AddSupplyValueFromFormProvider();