private void btnSuaCTHD_Click(object sender, EventArgs e)
 {
     try
     {
         int      tt   = (int.Parse(txtThanhTien.Text));
         DTO_CTHD cthd = new DTO_CTHD(int.Parse(txtMaHD.Text), int.Parse(cboTSP.SelectedValue.ToString()), int.Parse(num_SL.Value.ToString()), int.Parse(txtGiaBan.Text), tt);
         bshd.UpdateCTHD(cthd);
         XtraMessageBox.Show("Sửa thành công.");
         gdvCTHD.DataSource = bshd.getCTHD(int.Parse(txtMaHD.Text));
     }
     catch
     {
         XtraMessageBox.Show("Sửa thất bại.");
     }
 }