Push Notification with Asp.Net

void send(string regId)
{
    var applicationID = "xxxxxxxx";


    var SENDER_ID = "xxxxx";
    var value = txtMsg.Text;
    WebRequest tRequest;
    tRequest = WebRequest.Create("https://android.googleapis.com/gcm/send");
    tRequest.Method = "post";
    tRequest.ContentType = " application/x-www-form-urlencoded;charset=UTF-8";
    tRequest.Headers.Add(string.Format("Authorization: key={0}", applicationID));

    tRequest.Headers.Add(string.Format("Sender: id={0}", SENDER_ID));

    // string postData = "{ 'registration_id': [ '" + regId + "' ], 'data': {'message': '" + txtMsg.Text + "'}}";
    string postData = "collapse_key=score_update&time_to_live=108&delay_while_idle=1&data.message=" + value + "&data.time=" + System.DateTime.Now.ToString() + "&registration_id=" + regId + "";
    Console.WriteLine(postData);
    Byte[] byteArray = Encoding.UTF8.GetBytes(postData);
    tRequest.ContentLength = byteArray.Length;

    Stream dataStream = tRequest.GetRequestStream();
    dataStream.Write(byteArray, 0, byteArray.Length);
    dataStream.Close();

    WebResponse tResponse = tRequest.GetResponse();

    dataStream = tResponse.GetResponseStream();

    StreamReader tReader = new StreamReader(dataStream);

    String sResponseFromServer = tReader.ReadToEnd();

    lblStat.Text = sResponseFromServer;
    tReader.Close();
    dataStream.Close();
    tResponse.Close();
}