网上参考了一段代码，一运行就报错，请教高手

C# code

private void LoginButton_Click(object sender, RoutedEventArgs e)        {            GetStringAsync();        }        public void GetStringAsync()        {            string uriStr = "http://192.168.1.13/RouteMap/Client/Handler.ashx";            HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(uriStr);            request.Method = "POST";            request.ContentType = "application/x-www-form-urlencoded";                        request.BeginGetResponse(new AsyncCallback(GetRequestStreamCallback), request);                    }        private void GetRequestStreamCallback(IAsyncResult asyncResult)        {            HttpWebRequest webRequest = (HttpWebRequest)asyncResult.AsyncState;            Stream postStream = webRequest.EndGetRequestStream(asyncResult);                            string myData = "sub=ComMemberHandler&fn=login";            byte[] byteArray = System.Text.Encoding.UTF8.GetBytes(myData);            postStream.Write(byteArray,0,myData.Length);            postStream.Close();            webRequest.BeginGetResponse(new AsyncCallback(responseCallBack), webRequest);        }        public void responseCallBack(IAsyncResult asyncResult)        {            HttpWebRequest webRequest = (HttpWebRequest)asyncResult.AsyncState;            HttpWebResponse webResponse = (HttpWebResponse)webRequest.EndGetResponse(asyncResult);            Stream streamResponse = webResponse.GetResponseStream();            StreamReader streamRead = new StreamReader(streamResponse);            string responseString = streamRead.ReadToEnd();            MessageBox.Show(responseString);            streamResponse.Close();            streamRead.Close();                    }

从网上参考的用post与服务器交互数据的代码，每次运行到Stream postStream = webRequest.EndGetRequestStream(asyncResult);就报错，说值不在范围内，请问是为什么呢？

[解决办法]
晚些时候我QQ上给你发一份request的例子吧。看你这接连的问问题。
[解决办法]
你照着写都能写错。。。