protected void Page_Load(object sender, EventArgs e)
        {
            if (Session["loginId"] != null)
            {
                loginId = Convert.ToInt32(Session["loginId"].ToString());

                merchant merchant = new merchant(loginId);
                string apiKey = merchant.key;
                string siteId = merchant.merchURL;
                DataSet dataSetMerchantTransaction = merchant.MerchantTransaction(siteId, apiKey);
                gvTransaction.DataSource = dataSetMerchantTransaction;
                gvTransaction.DataBind();
            }
            else
                Response.Redirect("LoginPage.aspx");
        }