public ActionResult Paid(hoadon hd)
        {
            int     nv_id = (int)((UserLogin)System.Web.HttpContext.Current.Session[QuanLyCapNuoc.common.CommonConstants.NV_SESSION]).nv_id;
            BillDao db    = new BillDao();

            db.Paid(hd.hd_id, nv_id);
            return(RedirectToAction("Show", "Bill", new { hd.hd_id }));
        }