windows phone 7 通过Post提交URL到服务器,从服务器获取数据(比如登陆时候使用)

HttpWebRequest myRequest = (HttpWebRequest)WebRequest.Create(UrlManager.Login());
myRequest.Method = "POST";
myRequest.ContentType = "application/x-www-form-urlencoded";

myRequest.BeginGetRequestStream(new AsyncCallback(GetRequestStreamCallback), myRequest);

private void GetRequestStreamCallback(IAsyncResult asynchronousResult)
{
HttpWebRequest request = (HttpWebRequest)asynchronousResult.AsyncState;
System.IO.Stream postStream = request.EndGetRequestStream(asynchronousResult);

// Prepare Parameters String
string parametersString = "username=用户名&password=密码";
//foreach (KeyValuePair<string, string> parameter in parameters)
//{
//    parametersString = parametersString + (parametersString != "" ? "&" : "") + string.Format("{0}={1}", parameter.Key, parameter.Value);
//}

byte[] byteArray = System.Text.Encoding.UTF8.GetBytes(parametersString);
// Write to the request stream.
postStream.Write(byteArray, 0, parametersString.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;
HttpWebResponse response = (HttpWebResponse)request.EndGetResponse(asynchronousResult);
Stream streamResponse = response.GetResponseStream();
StreamReader streamRead = new StreamReader(streamResponse);
string responseString = streamRead.ReadToEnd();
// Close the stream object
streamResponse.Close();
streamRead.Close();
}