Question

I have trouble following the examples to get the callback.

I have the following code:

 private void startWebRequest(object sender, EventArgs e)
    {
        Uri url = new Uri("http://localhost.com/dummyGet");
        HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(url);
        request.BeginGetResponse(new AsyncCallback(ReadWebRequestCallback), request);
    }

    private void ReadWebRequestCallback(IAsyncResult callbackResult)
    { 
        Console.WriteLine("Don not get here");
        try
        {
            var req = (HttpWebRequest)callbackResult.AsyncState;
            using (var response = req.EndGetResponse(callbackResult))
            {
                Console.WriteLine("Code");
            }
        }
        catch
        {  }
    }

I have been bangin my head against this all day, I can see the get request in my browser, or with client in fiddler/wireshark. But the code (ReadWebRequestCallback) does not get called.

Edit:
Also note that if I use WebClient and DownloadStringAsync it works, but i need other HTTP status codes than 404 and 200.:

_client.DownloadStringCompleted += new DownloadStringCompletedEventHandler(DownloadStringCompleted);
_client.DownloadStringAsync(_concurrentCheckUrl);
}

private void DownloadStringCompleted(object sender, DownloadStringCompletedEventArgs e)
    {// Works, gets here}

Answer 1

Thanks so much for all the help!

I ended up with doing this like described in Simplify Async networking with Tasks in SL5 with tasks.

HttpWebRequest _request;

private void doGetRequest()
  _request = WebRequestCreator.ClientHttp.Create(new Uri("http://localhost/getDummy")) as HttpWebRequest;
        var webTask = Task.Factory.FromAsync<WebResponse>
            (_request.BeginGetResponse, _request.EndGetResponse, null)
          .ContinueWith(
            task =>
            {
                var response = (HttpWebResponse)task.Result;
                // The reason I use HttpRequest, not WebRequest, to get statuscode.
                if (response.StatusCode == HttpStatusCode.ServiceUnavailable)
                {
                     //Do Stuff
                }
            });

I do however think the problem relied in that my logging did not log when it was in the callback, this I cannot understand. But after banging my head to the wall for a day, I’ll leave that behind. But think my actual post would work.