private void SinhMaVach()
        {
            liMaVach = new List <MaVachInfor>();
            foreach (ItemInMaVachInfor sp in liSanPham)
            {
                if (sp.TrungMaVach == 1)//sinh trung ma vach
                {
                    List <MaVachInfor> mvs = UtilFunctions.GenTrungMaVach2(sp);
                    liMaVach.AddRange(mvs);
                }
                else//sinh khong trung ma vach
                {
                    List <MaVachInfor> mvs = UtilFunctions.GenKhongTrungMaVach(sp);
                    liMaVach.AddRange(mvs);
                }
            }
            gSanPham.DataSource = null;

            gSanPham.DataSource = new BindingList <MaVachInfor>(liMaVach);
        }