public void GetValueFromRequest(string postData)

        {

            var request = (HttpWebRequest) WebRequest.CreateHttp("http://login.test.geoop.com/oauth2/token");

            byte[] requestBytes =

                Encoding.UTF8.GetBytes(

                   postData);

            request.Method = "POST";

            request.ContentType = "application/x-www-form-urlencoded";

            request.ContentLength = requestBytes.Length;

            request.BeginGetRequestStream(GetRequestStreamCallback, request);

        }

        private static void GetRequestStreamCallback(IAsyncResult asynchronousResult)

        {

            var request = (HttpWebRequest) asynchronousResult.AsyncState;

            // End the operation

            var postStream = request.EndGetRequestStream(asynchronousResult);

            var postData = "grant_type=password&username=geooplive&password=geooppass&client_id=app4&scope=default";

            // Convert the string into a byte array.

            byte[] byteArray = Encoding.UTF8.GetBytes(postData);

            // Write to the request stream.

            postStream.Write(byteArray, 0, postData.Length);

            postStream.Close();

            // Start the asynchronous operation to get the response

            request.BeginGetResponse(GetResponseCallback, request);

        }

        private static void GetResponseCallback(IAsyncResult asynchronousResult)

        {

            var request = (HttpWebRequest)asynchronousResult.AsyncState;

            HttpWebResponse response = null;

            // End the operation

            try

            {

                response = (HttpWebResponse) request.EndGetResponse(asynchronousResult);

            }

            catch (WebException ex)

            {

                if (ex.Response != null)

                {

                }

            }

            if (response.StatusCode == HttpStatusCode.Accepted)

            {

                Debug.WriteLine(response.ToString());

            }

            var streamResponse = response.GetResponseStream();

            var streamRead = new StreamReader(streamResponse);

            var responseString = streamRead.ReadToEnd();

            Console.WriteLine(responseString);

            // Close the stream object

            streamResponse.Close();

            streamRead.Close();

            // Release the HttpWebResponse

            response.Close();

        }