private void btnChonDV_Click(object sender, EventArgs e)
        {
            Form_QuanLyDichVu f = new Form_QuanLyDichVu(maHD);

            f.On_HienThi += HienThiDSDichVuDaChon;
            f.ShowDialog();
        }
        private void button2_Click(object sender, EventArgs e)
        {
            Form_QuanLyDichVu f = new Form_QuanLyDichVu();

            f.ShowDialog();
        }