C# get parameter in url

 string clientIP = Request.Headers["X-Forwarded-For"];

            if (string.IsNullOrEmpty(clientIP))

                clientIP = Request.UserHostAddress;

Log.InfoFormat("Callback received from Smartfren: {0} [IP: {1}]", Request.Url, clientIP);

Request.QueryString["serviceType"]; => get parameter in url