public bool themHD(Hop_Dong th)
        {
            var t = (from a in db.Hop_Dongs where a.soHD == th.soHD select a).SingleOrDefault();

            if (t == null)
            {
                db.Hop_Dongs.InsertOnSubmit(t);
                //db.SubmitChanges();
                return(true);
            }
            return(false);
        }
        public bool suaHD(Hop_Dong th)
        {
            var t = (from a in db.Hop_Dongs where a.soHD == th.soHD select a).SingleOrDefault();

            if (t != null)
            {
                t.soHD       = th.soHD;
                t.soXe       = th.soXe;
                t.tenKH      = th.tenKH;
                t.triGiaHD   = th.triGiaHD;
                t.ng_NgThu   = th.ng_NgThu;
                t.ng_Giao_DK = th.ng_Giao_DK;
                t.ngayHD     = th.ngayHD;
                t.maKH       = th.maKH;
                t.diaChi     = th.diaChi;
                db.SubmitChanges();
                return(true);
            }
            return(false);
        }
 partial void UpdateHop_Dong(Hop_Dong instance);
 partial void DeleteHop_Dong(Hop_Dong instance);
 partial void InsertHop_Dong(Hop_Dong instance);