///Send SMS using C#

//Your APIkey

string apikey = "YourApiKey";
//Approved sender id(6 characters string only).

string senderId = "TESTIN";
//Message channel Promotional=1 or Transactional=2
string channel = "2";
//Default is 0 for normal message, Set 8 for unicode sms
string DCS = "0";
 //Default is 0 for normal sms, Set 1 for immediate display
string flashsms = "0";
//Recipient mobile number (pass with comma seprated if need to send on more then one number).

string number = "9999999";
//Your message to send, Add URL encoding here.

string message = HttpUtility.UrlEncode("Test message");
//Define route. 

string route = "default";


//Prepare you post parameters

StringBuilder sbPostData = new StringBuilder();

sbPostData.AppendFormat("authkey={0}", authKey);

sbPostData.AppendFormat("&number={0}", number);

sbPostData.AppendFormat("&message={0}", message);

sbPostData.AppendFormat("&sender={0}", senderId);

sbPostData.AppendFormat("&route={0}", "default");


try

{

    //Call Send SMS API

    string sendSMSUri = "https://www.smsgatewayhub.com/api/mt/SendSMS?";
    //Create HTTPWebrequest

    HttpWebRequest httpWReq = (HttpWebRequest)WebRequest.Create(sendSMSUri);
    //Prepare and Add URL Encoded data

    UTF8Encoding encoding = new UTF8Encoding();

    byte[] data = encoding.GetBytes(sbPostData.ToString());
    //Specify post method

    httpWReq.Method = "POST";

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

    httpWReq.ContentLength = data.Length;
    using (Stream stream = httpWReq.GetRequestStream())

    {

      stream.Write(data, 0, data.Length);

    }
    //Get the response

    HttpWebResponse response = (HttpWebResponse)httpWReq.GetResponse();

    StreamReader reader = new StreamReader(response.GetResponseStream());

    string responseString = reader.ReadToEnd();


    //Close the response

    reader.Close();

    response.Close();

}

catch (SystemException ex)

{

  MessageBox.Show(ex.Message.ToString());

}