Payment Gateway Integration in ASP.NET Application

protected void btnContinue_Click(object sender, EventArgs e)

    {

        //string strId = UserId_TextBox.Text;

        //string strName = Name_TextBox.Text;

        ASCIIEncoding encoding = new ASCIIEncoding();

        string postData = "ssl_merchant_id=" + System.Configuration.ConfigurationSettings.AppSettings.Get("userid");

        postData += ("&ssl_user_id=" + System.Configuration.ConfigurationSettings.AppSettings.Get("username"));

        postData += ("&ssl_pin=" + System.Configuration.ConfigurationSettings.AppSettings.Get("pinno"));

        postData += ("&ssl_show_form=" + "true");

        postData += ("&ssl_test_mode=" + "true");

        postData += ("&ssl_invoice_number" + "123-achbiz-001");

        postData += ("&ssl_transaction_type" + "ccsale");

        postData += ("&ssl_amount=" + "5.95");

        postData += ("&ssl_salestax" + "0.00");

        byte[] data = encoding.GetBytes(postData);

        // Prepare web request...

        HttpWebRequest myRequest =(HttpWebRequest)WebRequest.Create("https://www.myvirtualmerchant.com/VirtualMerchant/process.do");

    

        myRequest.Method = "POST";

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

        myRequest.ContentLength = data.Length;

        Stream newStream = myRequest.GetRequestStream();

        // Send the data.

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

        newStream.Close();

    }