C# · 12月 26, 2021

c# – 如何从asp.net处理程序返回404错误?

我创建了一个下载文件的处理程序.
如果文件不存在或用户无权下载该特定文件,我想返回404错误.

可能吗?如果是,怎么样?示例代码将不胜感激.

解决方法 检查此代码 public class MyHandler : IHttpHandler{ private const string CONSTSOMEPARAM = “SomeParam”; public MyHandler() { } public void ProcessRequest(HttpContext context) { // Don’t allow this response to be cached by the browser. // Note,you MIGHT want to allow it to be cached,depending on what you’re doing. context.Response.Cache.SetCacheability(HttpCacheability.NoCache); context.Response.Cache.SetNoStore(); context.Response.Cache.SetExpires(DateTime.MinValue); if (ValidateParameters(context) == false) { //Internal Server Error context.Response.StatusCode = 500; context.Response.End(); return; } if (context.User.Identity.IsAuthenticated == false) { //Forbidden context.Response.StatusCode = 403; context.Response.End(); return; } string someParam = context.Request.QueryString[CONSTSOMEPARAM]; SomethingReponse response = SomeService.someImportantThing(someParam); if (response.Header == null || response.Header.Success == false) { //Whatever wasn’t found context.Response.StatusCode = 404; context.Response.End(); return; } context.Response.ContentType = “somespecific/mimetype”; context.Response.BinaryWrite(); //or context.Response.Write(); //or context.Response.WriteFile(); //or someImageStream.Save(context.Response.OutputStream); } public bool ValidateParameters(HttpContext context) { //Validate some stuff…true if cool,false if not return false; } /// <summary> /// True if this handler can be reused between calls. That’s cool if you don’t have any class instance data. /// False if you’d rather get a fresh one. /// </summary> public bool IsReusable { get { return true; } }}