using System;
using System.Collections.Generic;
using System.Net;
using System.Collections.Specialized;
using System.IO;

namespace sendSMS
{
class sendSMS
{  
     
public string sendSMS()
{
String result;
string userName = "youremail@address.com";
string hash = "Your API hash";
string numbers = "917735838811"; // in a comma seperated list
string message = "This is your message";
string sender = "WEBADD";

String url = "http://sms.webadd.in/api2/send/?username=" + userName + "&hash="  + hash + "&numbers="  + numbers + 
"&message="  + message + "&sender="  + sender;
//refer to parameters to complete correct url string

StreamWriter myWriter = null;
HttpWebRequest objRequest = (HttpWebRequest)WebRequest.Create(url);

objRequest.Method = "POST";
objRequest.ContentLength = Encoding.UTF8.GetByteCount(url);
objRequest.ContentType = "application/x-www-form-urlencoded";
try
{
myWriter = new StreamWriter(objRequest.GetRequestStream());
myWriter.Write(url);
}
catch (Exception e)
{
return e.Message;
}
finally
{
myWriter.Close();
}

HttpWebResponse objResponse = (HttpWebResponse)objRequest.GetResponse();
using (StreamReader sr = new StreamReader(objResponse.GetResponseStream()))
{
result = sr.ReadToEnd();
// Close and clean up the StreamReader
sr.Close();
}
return result;
} 
}
}