Add support for BadRequest in RazorPages (#7097)

Addresses #7095

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

@@ -1750,7 +1750,7 @@ namespace Microsoft.AspNetCore.Mvc
         /// <summary>
         /// Creates an <see cref="BadRequestObjectResult"/> that produces a <see cref="StatusCodes.Status400BadRequest"/> response.
         /// </summary>
-        /// <param name="modelState">The model state dictionary containing errors to be returned to the client.</param>
+        /// <param name="modelState">The <see cref="ModelStateDictionary" /> containing errors to be returned to the client.</param>
         /// <returns>The created <see cref="BadRequestObjectResult"/> for the response.</returns>
         [NonAction]
         public virtual BadRequestObjectResult BadRequest(ModelStateDictionary modelState)
@@ -1787,7 +1787,7 @@ namespace Microsoft.AspNetCore.Mvc
         /// <summary>
         /// Creates an <see cref="UnprocessableEntityObjectResult"/> that produces a <see cref="StatusCodes.Status422UnprocessableEntity"/> response.
         /// </summary>
-        /// <param name="modelState">The model state dictionary containing errors to be returned to the client.</param>
+        /// <param name="modelState">The <see cref="ModelStateDictionary" /> containing errors to be returned to the client.</param>
         /// <returns>The created <see cref="UnprocessableEntityObjectResult"/> for the response.</returns>
         [NonAction]
         public virtual UnprocessableEntityObjectResult UnprocessableEntity(ModelStateDictionary modelState)
@@ -1820,7 +1820,7 @@ namespace Microsoft.AspNetCore.Mvc
         /// <summary>
         /// Creates an <see cref="ConflictObjectResult"/> that produces a <see cref="StatusCodes.Status409Conflict"/> response.
         /// </summary>
-        /// <param name="modelState">The model state dictionary containing errors to be returned to the client.</param>
+        /// <param name="modelState">The <see cref="ModelStateDictionary" /> containing errors to be returned to the client.</param>
         /// <returns>The created <see cref="ConflictObjectResult"/> for the response.</returns>
         [NonAction]
         public virtual ConflictObjectResult Conflict(ModelStateDictionary modelState)

src/Microsoft.AspNetCore.Mvc.RazorPages/PageBase.cs

@@ -145,6 +145,39 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages
             }
         }
 
+        /// <summary>
+        /// Creates a <see cref="BadRequestResult"/> that produces a <see cref="StatusCodes.Status400BadRequest"/> response.
+        /// </summary>
+        /// <returns>The created <see cref="BadRequestResult"/> for the response.</returns>
+        [NonAction]
+        public virtual BadRequestResult BadRequest()
+            => new BadRequestResult();
+
+        /// <summary>
+        /// Creates a <see cref="BadRequestObjectResult"/> that produces a <see cref="StatusCodes.Status400BadRequest"/> response.
+        /// </summary>
+        /// <param name="error">An error object to be returned to the client.</param>
+        /// <returns>The created <see cref="BadRequestObjectResult"/> for the response.</returns>
+        [NonAction]
+        public virtual BadRequestObjectResult BadRequest(object error)
+            => new BadRequestObjectResult(error);
+
+        /// <summary>
+        /// Creates a <see cref="BadRequestObjectResult"/> that produces a <see cref="StatusCodes.Status400BadRequest"/> response.
+        /// </summary>
+        /// <param name="modelState">The <see cref="ModelStateDictionary" /> containing errors to be returned to the client.</param>
+        /// <returns>The created <see cref="BadRequestObjectResult"/> for the response.</returns>
+        [NonAction]
+        public virtual BadRequestObjectResult BadRequest(ModelStateDictionary modelState)
+        {
+            if (modelState == null)
+            {
+                throw new ArgumentNullException(nameof(modelState));
+            }
+
+            return new BadRequestObjectResult(modelState);
+        }
+
         /// <summary>
         /// Creates a <see cref="ChallengeResult"/>.
         /// </summary>

src/Microsoft.AspNetCore.Mvc.RazorPages/PageModel.cs

@@ -520,6 +520,39 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages
                 propertyFilter);
         }
 
+        /// <summary>
+        /// Creates a <see cref="BadRequestResult"/> that produces a <see cref="StatusCodes.Status400BadRequest"/> response.
+        /// </summary>
+        /// <returns>The created <see cref="BadRequestResult"/> for the response.</returns>
+        [NonAction]
+        public virtual BadRequestResult BadRequest()
+            => new BadRequestResult();
+
+        /// <summary>
+        /// Creates a <see cref="BadRequestObjectResult"/> that produces a <see cref="StatusCodes.Status400BadRequest"/> response.
+        /// </summary>
+        /// <param name="error">An error object to be returned to the client.</param>
+        /// <returns>The created <see cref="BadRequestObjectResult"/> for the response.</returns>
+        [NonAction]
+        public virtual BadRequestObjectResult BadRequest(object error)
+            => new BadRequestObjectResult(error);
+
+        /// <summary>
+        /// Creates a <see cref="BadRequestObjectResult"/> that produces a <see cref="StatusCodes.Status400BadRequest"/> response.
+        /// </summary>
+        /// <param name="modelState">The <see cref="ModelStateDictionary" /> containing errors to be returned to the client.</param>
+        /// <returns>The created <see cref="BadRequestObjectResult"/> for the response.</returns>
+        [NonAction]
+        public virtual BadRequestObjectResult BadRequest(ModelStateDictionary modelState)
+        {
+            if (modelState == null)
+            {
+                throw new ArgumentNullException(nameof(modelState));
+            }
+
+            return new BadRequestObjectResult(modelState);
+        }
+
         /// <summary>
         /// Creates a <see cref="ChallengeResult"/>.
         /// </summary>

test/Microsoft.AspNetCore.Mvc.FunctionalTests/RazorPagesTest.cs

@@ -291,6 +291,20 @@ namespace Microsoft.AspNetCore.Mvc.FunctionalTests
             Assert.Equal(HttpStatusCode.NotFound, response.StatusCode);
         }
 
+        [Fact]
+        public async Task PageHandlerCanReturnBadRequest()
+        {
+            // Arrange
+            var request = new HttpRequestMessage(HttpMethod.Get, "http://localhost/Pages/HandlerWithParameter");
+
+            // Act
+            var response = await Client.SendAsync(request);
+
+            // Assert
+            Assert.Equal(HttpStatusCode.BadRequest, response.StatusCode);
+            Assert.Equal("Parameter cannot be null.", await response.Content.ReadAsStringAsync());
+        }
+
         [Fact]
         public async Task HelloWorld_CanGetContent()
         {

test/Microsoft.AspNetCore.Mvc.RazorPages.Test/PageModelTest.cs

@@ -1495,6 +1495,35 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages
             Assert.Equal(StatusCodes.Status401Unauthorized, result.StatusCode);
         }
 
+        [Fact]
+        public void BadRequest_SetsStatusCode()
+        {
+            // Arrange
+            var page = new TestPage();
+
+            // Act
+            var result = page.BadRequest();
+
+            // Assert
+            Assert.IsType<BadRequestResult>(result);
+            Assert.Equal(StatusCodes.Status400BadRequest, result.StatusCode);
+        }
+
+        [Fact]
+        public void BadRequest_SetsStatusCodeAndResponseContent()
+        {
+            // Arrange
+            var page = new TestPage();
+
+            // Act
+            var result = page.BadRequest("Test Content");
+
+            // Assert
+            Assert.IsType<BadRequestObjectResult>(result);
+            Assert.Equal(StatusCodes.Status400BadRequest, result.StatusCode);
+            Assert.Equal("Test Content", result.Value);
+        }
+
         [Fact]
         public void NotFound_SetsStatusCode()
         {

test/Microsoft.AspNetCore.Mvc.RazorPages.Test/PageTest.cs

@@ -1486,6 +1486,35 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages
             Assert.Equal(StatusCodes.Status401Unauthorized, result.StatusCode);
         }
 
+        [Fact]
+        public void BadRequest_SetsStatusCode()
+        {
+            // Arrange
+            var page = new TestPage();
+
+            // Act
+            var result = page.BadRequest();
+
+            // Assert
+            Assert.IsType<BadRequestResult>(result);
+            Assert.Equal(StatusCodes.Status400BadRequest, result.StatusCode);
+        }
+
+        [Fact]
+        public void BadRequest_SetsStatusCodeAndResponseContent()
+        {
+            // Arrange
+            var page = new TestPage();
+
+            // Act
+            var result = page.BadRequest("Test Content");
+
+            // Assert
+            Assert.IsType<BadRequestObjectResult>(result);
+            Assert.Equal(StatusCodes.Status400BadRequest, result.StatusCode);
+            Assert.Equal("Test Content", result.Value);
+        }
+
         [Fact]
         public void NotFound_SetsStatusCode()
         {

test/WebSites/RazorPagesWebSite/HelloWorldWithPageModelAttributeModel.cs

@@ -1,7 +1,6 @@
 // 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.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Mvc.RazorPages.Infrastructure;
 
 namespace RazorPagesWebSite

test/WebSites/RazorPagesWebSite/HelloWorldWithPageModelHandler.cs

@@ -1,7 +1,6 @@
 // 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.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Mvc.RazorPages;
 
 namespace RazorPagesWebSite

test/WebSites/RazorPagesWebSite/ModelWithPageFilter.cs

@@ -3,7 +3,6 @@
 
 using System;
 using System.Linq;
-using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Mvc.Filters;
 using Microsoft.AspNetCore.Mvc.RazorPages;
 

test/WebSites/RazorPagesWebSite/Pages/HandlerWithParameter.cshtml

@@ -0,0 +1,5 @@
+@page
+@model HandlerWithParameterModel
+@{
+}
+Handler with parameter

test/WebSites/RazorPagesWebSite/Pages/HandlerWithParameter.cshtml.cs

@@ -0,0 +1,21 @@
+// 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.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Mvc.RazorPages;
+
+namespace RazorPagesWebSite.Pages
+{
+    public class HandlerWithParameterModel : PageModel
+    {
+        public IActionResult OnGet(string testParameter = null)
+        {
+            if (testParameter == null)
+            {
+                return BadRequest("Parameter cannot be null.");
+            }
+
+            return Page();
+        }
+    }
+}