Return a value from a async method call in WP8 C#

I am developing a mobile app from which I am sending an HTTP POST request containing XML for user authentication purpose to a PHP based web service.

The response from the web service is received in the method GetResponseCallback(IAsyncResult asynchronousResult).

See the some portion of the code given below for sending the request.

class XMLHttpRequestHandler { private HttpWebRequest vWebRequestObj; private string vXMLString; private string vResponse; public void SendXMLHttpRequest(string pXMLString) { vWebRequestObj = (HttpWebRequest)HttpWebRequest.CreateHttp("https://test.mydomain.com/mywebservice.php"); vWebRequestObj.Method = "PUT"; vWebRequestObj.ContentType = "text/xml; charset=utf-8"; // initialize the XML string vXMLString = pXMLString; // Convert the string into a byte array and calculate the length. vWebRequestObj.ContentLength = Encoding.UTF8.GetBytes(vXMLString).Length; // start the asynchronous operation vWebRequestObj.BeginGetRequestStream(new AsyncCallback(GetRequestStreamCallback), vWebRequestObj); } private void GetRequestStreamCallback(IAsyncResult asynchronousResult) { // create the WebRequestObject HttpWebRequest vWebRequestObj = (HttpWebRequest)asynchronousResult.AsyncState; // End the operation and get the stream for writing the XML. Stream postStream = vWebRequestObj.EndGetRequestStream(asynchronousResult); // Convert the string into a byte array. byte[] byteArray = Encoding.UTF8.GetBytes(vXMLString); // Write to the request stream. postStream.Write(byteArray, 0, byteArray.Length); postStream.Close(); // Start the asynchronous operation to get the response vWebRequestObj.BeginGetResponse(new AsyncCallback(GetResponseCallback), vWebRequestObj); } private void GetResponseCallback(IAsyncResult asynchronousResult) { // create the WebRequestObject HttpWebRequest vWebRequestObj = (HttpWebRequest)asynchronousResult.AsyncState; // End the operation HttpWebResponse vWebResponseObj = (HttpWebResponse)vWebRequestObj.EndGetResponse(asynchronousResult); // get the response stream Stream ResponseStream = vWebResponseObj.GetResponseStream(); // create the stream reader object StreamReader ResponseStreamReader = new StreamReader(ResponseStream); // read the stream vResponse = ResponseStreamReader.ReadToEnd(); // output the stream System.Diagnostics.Debug.WriteLine(vResponse); // Close the stream object ResponseStream.Close(); ResponseStreamReader.Close(); // Release the HttpWebResponse vWebResponseObj.Close(); } } 

I am calling the method SendXMLHttpRequest(string pXMLString) from some other class in my project like this

string XMLString = "<testxml><username>abcd</username><password>xyz</password></testxml>"; // send the XML HTTP request XMLHttpRequestHandler ob = new XMLHttpRequestHandler(); string webserviceresponse = ob.SendXMLHttpRequest(XMLString); 

The problem I am facing is that I am not able to figure out how can I receive the response string in the variable webserviceresponse in the calling code. How can I solve this ?