protected void lbtnDelete_Click(object sender, EventArgs e)
        {
            List <object> fieldValues = ASPxGridView1_Order.GetSelectedFieldValues(new string[] { "ID" });

            foreach (var item in fieldValues)
            {
                _OrderRepo.Remove(Utils.CIntDef(item));
            }
            Response.Redirect("danh-sach-don-hang.aspx");
        }