阻止Windows Phone中的异步操作

Question

I am trying send the http post from the windows phone to the server and I am getting some of problem via sending the post data.I put the break point in button_click_1 function and I found that it would not start the asynronous operation . Beside that, it also block the current thread and I know that this situation is cause by the allDone.waitOne() .

Why the asynronous operation will not function and how to solve it?

Thank you for any help.

private void Button_Click_1(object sender, RoutedEventArgs e)
            {
            // Create a new HttpWebRequest object.
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);

            request.ContentType = "application/x-www-form-urlencoded";

            request.Method = "POST";

            // start the asynchronous operation
            request.BeginGetRequestStream(new AsyncCallback(GetRequestStreamCallback), request);

            allDone.WaitOne();

        }

Asynronous operation :

private void GetRequestStreamCallback(IAsyncResult asynchronousResult)
        {
            HttpWebRequest request = (HttpWebRequest)asynchronousResult.AsyncState;


            // End the operation
            Stream postStream = request.EndGetRequestStream(asynchronousResult);

            string postData = "xxxxxxxxxxx";    
            // Convert the string into a byte array. 
            byte[] byteArray = Encoding.UTF8.GetBytes(postData);

            // Write to the request stream.
            postStream.Write(byteArray, 0, postData.Length);
            postStream.Close();

            // Start the asynchronous operation to get the response
            request.BeginGetResponse(new AsyncCallback(GetResponseCallback), request);
        }

        private void GetResponseCallback(IAsyncResult asynchronousResult)
        {
            HttpWebRequest request = (HttpWebRequest)asynchronousResult.AsyncState;

            // End the operation
            HttpWebResponse response = (HttpWebResponse)request.EndGetResponse(asynchronousResult);
            Stream streamResponse = response.GetResponseStream();
            StreamReader streamRead = new StreamReader(streamResponse);
            string responseString = streamRead.ReadToEnd();
            tbtesting.Text = responseString.ToString();

            streamResponse.Close();
            streamRead.Close();

            response.Close();
            allDone.Set();
        }

Answer 1

You're not the first to hit this (see Is it possible to make synchronous network call on ui thread in wpf (windows phone) ). If you do this then you deadlock the UI thread on Windows Phone.

The closest you're going to get is to use the async/await on your network calls. There are extension methods you can use to do this as part of the Microsoft.Bcl.Async package on NuGet.