void Link_Click(object sender, EventArgs e)
        {
            int            idLH = ((sender as LinkLabel).Tag as LichHen).Id;
            LichHen        lh   = LichHenDAO.Instance.getChitietLichHen(idLH);
            ChiTietLichHen ctlh = new ChiTietLichHen(lh);

            ctlh.ShowDialog();
        }
        void Link_Click(object sender, EventArgs e)
        {
            int            idLH = ((sender as LinkLabel).Tag as LichHen).Id;
            LichHen        lh   = LichHenDAO.Instance.getChitietLichHen(idLH);
            ChiTietLichHen ctlh = new ChiTietLichHen(lh);

            ctlh.ShowDialog();
            flp_Day.Controls.Clear();
            Load_tatca_velichhen();
        }