Create Push Notification

01.using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Net;
using System.Text;
using System.IO;
 protected void Button1_Click(object sender, EventArgs e)
 {

//Registration Id created by Android App i.e. DeviceId.  
string regId;  
regId = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";   
//API Key created in Google project  
var applicationID = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";   
  
//Project ID created in Google project.  
 var SENDER_ID = "xxxxxxxxxxxx";   
 var varMessage = "Hello! How are you?";  
 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 postDataToServer = "collapse_key=score_update&time_to_live=108&delay_while_idle=1&data.message="  
                    + varMessage + "&data.time=" + System.DateTime.Now.ToString() + "®istration_id=" + regId + "";  
  
  
Console.WriteLine(postDataToServer);  
Byte[] byteArray = Encoding.UTF8.GetBytes(postDataToServer);  
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();  
  
tReader.Close();  
dataStream.Close();  
tResponse.Close();  
}

using (var client = new HttpClient())
{
    client.BaseAddress = new Uri("http://localhost:9000/");
    client.DefaultRequestHeaders.Accept.Clear();
    client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

    // New code:
    HttpResponseMessage response = await client.GetAsync("api/products/1");
    if (response.IsSuccessStatusCode)
    {
        Product product = await response.Content.ReadAsAsync>Product>();
        Console.WriteLine("{0}\t${1}\t{2}", product.Name, product.Price, product.Category);
    }
}