ASP.NET異步處理內容類型不發送

我有這樣的異步處理ASP.NET異步處理內容類型不發送

public sealed class ImageTransferHandler : IHttpAsyncHandler 
{ 
    public bool IsReusable { get { return false; } } 

    public ImageTransferHandler() 
    { 
    } 
    public IAsyncResult BeginProcessRequest(HttpContext context, AsyncCallback cb, Object extraData) 
    { 
     string url = context.Server.UrlDecode(context.Request.QueryString["url"]); 

     ImageTransferOperation ito = new ImageTransferOperation(cb, context, extraData); 
     ito.Start(url); 
     return ito; 
    } 

    public void EndProcessRequest(IAsyncResult result) 
    { 
    } 

    public void ProcessRequest(HttpContext context) 
    { 
     throw new InvalidOperationException(); 
    } 

    private class ImageTransferOperation : IAsyncResult 
    { 
     private Object state; 
     private bool isCompleted; 
     private AsyncCallback cb; 
     private HttpContext context; 

     public WaitHandle AsyncWaitHandle 
     { 
      get { return null; } 
     } 

     public bool CompletedSynchronously 
     { 
      get { return false; } 
     } 

     public bool IsCompleted 
     { 
      get { return isCompleted; } 
     } 

     public Object AsyncState 
     { 
      get { return state; } 
     } 

     public ImageTransferOperation(AsyncCallback cb, HttpContext context, Object state) 
     { 
      this.cb = cb; 
      this.context = context; 
      this.state = state; 
      this.isCompleted = false; 
     } 

     public void Start(string url) 
     { 
      ThreadPool.QueueUserWorkItem(new WaitCallback(StartTransfer), url); 
     } 

     private void StartTransfer(Object state) 
     { 
      string url = (string)state; 

      System.Net.WebClient wc = new System.Net.WebClient(); 

      byte[] bytes = wc.DownloadData(url); 

      context.Response.Headers.Add("Content-Type", "image/jpeg"); 
      context.Response.Headers.Add("Content-Length", bytes.Length.ToString()); 
      context.Response.BinaryWrite(bytes); 

      isCompleted = true; 
      cb(this); 
     } 
    } 
}

一切正常，只是「內容類型」標頭不發送。我試圖用

context.Response.Headers.Add("Content-Type", "image/jpeg");

和

context.Response.Headers["Content-Type"] = "image/jpeg";

，該怎麼辦錯把它兩者兼而有之？

來源

2011-06-06 aikixd

試過Response.ContentType？ – Nathan 2011-06-06 11:09:02

太棒了！感謝名單。我不知道這個頭是異常的。非常直觀的控制。 – aikixd 2011-06-06 11:12:43

沒問題 - 看到工作，請接受答案，下面添加:) – Nathan 2011-06-07 07:17:53

使用Response.ContentType。很高興爲你工作:)

來源

2011-06-07 07:17:18 Nathan

ASP.NET異步處理內容類型不發送

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