Hi John,

Thanks a lot for your post. My configuration is: .NET 2.0.50727, Visual
Studio 2005 and I am using C#. I don't know anything about the server
other than I can POST files to a URI. Also, the way I am using
HttpWebRequest is taken from the MSDN pages. The actual Abort() in my
application works ok, but the upload does not stop.

I am not quite sure what you mean by:

My understanding so far was that calling GetResponse starts the actual
POSTing of the file, because this is when I see the network becoming
quite busy, but I may be wrong here. From your sentence above I gather
that POSTing to the server occurs before calling GetResponse, maybe when
I write to the request stream? And GetResponse only waits for the
response from the server. Is that correct?

I think your understanding of my problem is correct, but it is not the
server that keeps sending data, it seems that my machine keeps sending
data to the server. When I start my app and I abort the upload a few
seconds later, a 1.6 MB file will still be uploaded.

Here is a short code snippet. This is an async version. The scenario is:
My Background worker thread calls Upload and then the GUI thread calls
Abort. BeginGetResponse will be aborted correctly, but the file keeps on
being uploaded.

public void Abort()
{
   this.req.Abort();
}

public void Upload(Uri uri)
{
try
{
   this.req = (WebRequest.Create(uri) as HttpWebRequest);
   this.req.Method = "POST";

   this.postData = new MemoryStream();

   /* Create data to POST */

   this.req.ContentLength = this.postData.Length;
   this.req.BeginGetRequestStream(
             new AsyncCallback(ReadCallback), this.req);

   allDone.WaitOne();
   allDone.Reset();

   IAsyncResult rest = this.req.BeginGetResponse(new
                          AsyncCallback(RespCallback), this.req);

   allDone.WaitOne();
}
catch (Exception exc)
{
   Console.WriteLine("WebRequest aborted");
   Console.WriteLine(exc.Message);
}
}

// First Callback
private void ReadCallback(IAsyncResult asynchronousResult)
{
    HttpWebRequest request = (HttpWebRequest)asynchronousResult.AsyncState;

    using (Stream s = request.EndGetRequestStream(asynchronousResult))
        this.postData.WriteTo(s);
    this.postData.Close();

    allDone.Set();
}

// Second Callback
private void RespCallback(IAsyncResult asynchronousResult)
{
    try
    {
         HttpWebRequest request =
(HttpWebRequest)asynchronousResult.AsyncState;
         HttpWebResponse response =
(HttpWebResponse)request.EndGetResponse(asynchronousResult);

         StreamReader sr = new StreamReader(response.GetResponseStream());
         string strResp = sr.ReadToEnd().Trim();

        allDone.Set();
    }
    catch (WebException e)
    {
        Debug.WriteLine("\nRespCallback Exception raised!");
        Debug.WriteLine("\nMessage:{0}", e.Message);
    }
}

Thanks again for your help.

Best wishes,

Marc.

John Saunders [MVP] schrieb: