asp.net - 返回新的RedirectResult()与返回Redirect()

Question

以下两个 Controller ActionResult返回语句之间有什么区别:

return new RedirectResult("http://www.google.com", false);

和

return Redirect("http://www.google.com");

Answer 1

直接来自 source

// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved. See License.txt in the project root for license information.

using System.Diagnostics.CodeAnalysis;
using System.Web.Mvc.Properties;

namespace System.Web.Mvc
{
    // represents a result that performs a redirection given some URI
    public class RedirectResult : ActionResult
    {
        [SuppressMessage("Microsoft.Design", "CA1054:UriParametersShouldNotBeStrings", MessageId = "0#", Justification = "Response.Redirect() takes its URI as a string parameter.")]
        public RedirectResult(string url)
            : this(url, permanent: false)
        {
        }

        [SuppressMessage("Microsoft.Design", "CA1054:UriParametersShouldNotBeStrings", MessageId = "0#", Justification = "Response.Redirect() takes its URI as a string parameter.")]
        public RedirectResult(string url, bool permanent)
        {
            if (String.IsNullOrEmpty(url))
            {
                throw new ArgumentException(MvcResources.Common_NullOrEmpty, "url");
            }

            Permanent = permanent;
            Url = url;
        }

        public bool Permanent { get; private set; }

        [SuppressMessage("Microsoft.Design", "CA1056:UriPropertiesShouldNotBeStrings", Justification = "Response.Redirect() takes its URI as a string parameter.")]
        public string Url { get; private set; }

        public override void ExecuteResult(ControllerContext context)
        {
            if (context == null)
            {
                throw new ArgumentNullException("context");
            }
            if (context.IsChildAction)
            {
                throw new InvalidOperationException(MvcResources.RedirectAction_CannotRedirectInChildAction);
            }

            string destinationUrl = UrlHelper.GenerateContentUrl(Url, context.HttpContext);
            context.Controller.TempData.Keep();

            if (Permanent)
            {
                context.HttpContext.Response.RedirectPermanent(destinationUrl, endResponse: false);
            }
            else
            {
                context.HttpContext.Response.Redirect(destinationUrl, endResponse: false);
            }
        }
    }
}

第二个参数确定是否为response is a 302 (temporary) or 301 permanent redirection。默认情况下，值为false。

第二种方法是在Controller上，它只是一种便捷方法。这种方法已经存在于许多MVC版本中(至少可以追溯到至少2个)，但是IIRC，我认为MVC 4中已经在RedirectResult中添加了Permanent部分(我不记得在MVC 3)。

// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved. See License.txt in the project root for license information.

using System.Diagnostics.CodeAnalysis;
using System.Globalization;
using System.IO;
using System.Security.Principal;
using System.Text;
using System.Web.Mvc.Async;
using System.Web.Mvc.Properties;
using System.Web.Profile;
using System.Web.Routing;
namespace System.Web.Mvc
{
    [SuppressMessage("Microsoft.Maintainability", "CA1506:AvoidExcessiveClassCoupling", Justification = "Class complexity dictated by public surface area")]
    public abstract class Controller : ControllerBase, IActionFilter, IAuthorizationFilter, IDisposable, IExceptionFilter, IResultFilter, IAsyncController, IAsyncManagerContainer
    {
      // omitted for brevity

      [SuppressMessage("Microsoft.Design", "CA1054:UriParametersShouldNotBeStrings", MessageId = "0#", Justification = "Response.Redirect() takes its URI as a string parameter.")]
      protected internal virtual RedirectResult Redirect(string url)
      {
          if (String.IsNullOrEmpty(url))
          {
              throw new ArgumentException(MvcResources.Common_NullOrEmpty, "url");
          }

          return new RedirectResult(url);
      }
    }
}