网上参考了一段代码，一运行就报错，请教高手
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(); }