wp7和web服务器进行交互,把网址发到服务端并接收服务端发回的消息

如果要和web服务器进行交互，发出的是http:// ....../Handler.ashx?id=xxx&pwd=xxx
怎样把这个发到服务端并接收服务端发回的消息？
用HttpWebRequest发请求
用GetResponseStream获得响应的数据流
  public void GetStringAsync()
        {
            Uri uri = new Uri(@"http:// ....../Handler.ashx?id=xxx&pwd=xxx");
           

            WebRequest request= WebRequest.Create(sb.ToString());
            //开始请求
            request.BeginGetResponse(new AsyncCallback(GetStringComplete), request);
        }

        private void GetStringComplete(IAsyncResult asyncResult)
        {
            try
            {
                HttpWebRequest webRequest = (HttpWebRequest)asyncResult.AsyncState;
                HttpWebResponse webResponse = (HttpWebResponse)webRequest.EndGetResponse(asyncResult);
                //得到响应流
                Stream streamResult = webResponse.GetResponseStream();
                StreamReader reader = new StreamReader(streamResult);
                //获取的返回值
                string resultString = reader.ReadToEnd();
                Deployment.Current.Dispatcher.BeginInvoke(delegate()
                {
                    //在ui中使用resultString
                 });
            }
            catch (WebException ex)
            {                
            }
        }