Add IStatusCodeActionResult (aspnet#8265)

* Add IStatusCodeActionResult
* Add unit test for explicitly implemented property on StatusCodeResult

src/Microsoft.AspNetCore.Mvc.Core/ContentResult.cs

@@ -9,7 +9,7 @@
 
 namespace Microsoft.AspNetCore.Mvc
 {
-    public class ContentResult : ActionResult
+    public class ContentResult : ActionResult, IStatusCodeActionResult
     {
         /// <summary>
         /// Gets or set the content representing the body of the response.

src/Microsoft.AspNetCore.Mvc.Core/Infrastructure/IStatusCodeActionResult.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.
+
+namespace Microsoft.AspNetCore.Mvc.Infrastructure
+{
+    /// <summary>
+    /// Represents an <see cref="IActionResult"/> that when executed will
+    /// produce an HTTP response with the specified <see cref="StatusCode"/>.
+    /// </summary>
+    public interface IStatusCodeActionResult : IActionResult
+    {
+        /// <summary>
+        /// Gets or sets the HTTP status code.
+        /// </summary>
+        int? StatusCode { get; }
+    }
+}

src/Microsoft.AspNetCore.Mvc.Core/ObjectResult.cs

@@ -9,7 +9,7 @@
 
 namespace Microsoft.AspNetCore.Mvc
 {
-    public class ObjectResult : ActionResult
+    public class ObjectResult : ActionResult, IStatusCodeActionResult
     {
         public ObjectResult(object value)
         {

src/Microsoft.AspNetCore.Mvc.Core/StatusCodeResult.cs

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using Microsoft.AspNetCore.Mvc.Infrastructure;
 using Microsoft.AspNetCore.Mvc.Internal;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Logging;
@@ -12,7 +13,7 @@ namespace Microsoft.AspNetCore.Mvc
     /// Represents an <see cref="ActionResult"/> that when executed will
     /// produce an HTTP response with the given response status code.
     /// </summary>
-    public class StatusCodeResult : ActionResult
+    public class StatusCodeResult : ActionResult, IStatusCodeActionResult
     {
         /// <summary>
         /// Initializes a new instance of the <see cref="StatusCodeResult"/> class
@@ -29,6 +30,8 @@ public StatusCodeResult(int statusCode)
         /// </summary>
         public int StatusCode { get; }
 
+        int? IStatusCodeActionResult.StatusCode => StatusCode;
+
         /// <inheritdoc />
         public override void ExecuteResult(ActionContext context)
         {

src/Microsoft.AspNetCore.Mvc.Formatters.Json/JsonResult.cs

@@ -4,6 +4,7 @@
 using System;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Mvc.Formatters.Json.Internal;
+using Microsoft.AspNetCore.Mvc.Infrastructure;
 using Microsoft.Extensions.DependencyInjection;
 using Newtonsoft.Json;
 
@@ -12,7 +13,7 @@ namespace Microsoft.AspNetCore.Mvc
     /// <summary>
     /// An action result which formats the given object as JSON.
     /// </summary>
-    public class JsonResult : ActionResult
+    public class JsonResult : ActionResult, IStatusCodeActionResult
     {
         /// <summary>
         /// Creates a new <see cref="JsonResult"/> with the given <paramref name="value"/>.

src/Microsoft.AspNetCore.Mvc.ViewFeatures/PartialViewResult.cs

@@ -14,7 +14,7 @@ namespace Microsoft.AspNetCore.Mvc
     /// <summary>
     /// Represents an <see cref="ActionResult"/> that renders a partial view to the response.
     /// </summary>
-    public class PartialViewResult : ActionResult
+    public class PartialViewResult : ActionResult, IStatusCodeActionResult
     {
         /// <summary>
         /// Gets or sets the HTTP status code.

src/Microsoft.AspNetCore.Mvc.ViewFeatures/ViewComponentResult.cs

@@ -13,7 +13,7 @@ namespace Microsoft.AspNetCore.Mvc
     /// <summary>
     /// An <see cref="IActionResult"/> which renders a view component to the response.
     /// </summary>
-    public class ViewComponentResult : ActionResult
+    public class ViewComponentResult : ActionResult, IStatusCodeActionResult
     {
         /// <summary>
         /// Gets or sets the arguments provided to the view component.

src/Microsoft.AspNetCore.Mvc.ViewFeatures/ViewResult.cs

@@ -14,7 +14,7 @@ namespace Microsoft.AspNetCore.Mvc
     /// <summary>
     /// Represents an <see cref="ActionResult"/> that renders a view to the response.
     /// </summary>
-    public class ViewResult : ActionResult
+    public class ViewResult : ActionResult, IStatusCodeActionResult
     {
         /// <summary>
         /// Gets or sets the HTTP status code.

test/Microsoft.AspNetCore.Mvc.Core.Test/HttpStatusCodeResultTests.cs

@@ -3,6 +3,7 @@
 
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc.Abstractions;
+using Microsoft.AspNetCore.Mvc.Infrastructure;
 using Microsoft.AspNetCore.Routing;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Logging;
@@ -32,6 +33,19 @@ public void HttpStatusCodeResult_ExecuteResultSetsResponseStatusCode()
             Assert.Equal(StatusCodes.Status404NotFound, httpContext.Response.StatusCode);
         }
 
+        [Fact]
+        public void HttpStatusCodeResult_ReturnsCorrectStatusCodeAsIStatusCodeActionResult()
+        {
+            // Arrange
+            var result = new StatusCodeResult(StatusCodes.Status404NotFound);
+
+            // Act
+            var statusResult = result as IStatusCodeActionResult;
+
+            // Assert
+            Assert.Equal(StatusCodes.Status404NotFound, statusResult?.StatusCode);
+        }
+
         private static IServiceCollection CreateServices()
         {
             var services = new ServiceCollection();