private void btnThemHD_ItemClick(object sender, DevExpress.XtraBars.ItemClickEventArgs e)
        {
            FrmHoaDonSC frm = new FrmHoaDonSC(con, "them", "");

            frm.btn_btn.Text = "Thêm mới";
            frm.Show();
        }
        private void btnCapnhatHD_ItemClick(object sender, DevExpress.XtraBars.ItemClickEventArgs e)
        {
            FrmHoaDonSC frm = new FrmHoaDonSC(con, "capnhat", grV_hoadon.GetRowCellValue(grV_hoadon.FocusedRowHandle, "ma").ToString());

            frm.btn_btn.Text = "Cập nhật";

            frm.txtMaHD.Text     = grV_hoadon.GetRowCellValue(grV_hoadon.FocusedRowHandle, "hienthima").ToString();
            frm.txtNguoicap.Text = grV_hoadon.GetRowCellValue(grV_hoadon.FocusedRowHandle, "nguoicap").ToString();
            frm.dtp_ngaycap.Text = grV_hoadon.GetRowCellValue(grV_hoadon.FocusedRowHandle, "ngaycap").ToString();
            frm.txt_dvsc.Text    = grV_hoadon.GetRowCellValue(grV_hoadon.FocusedRowHandle, "donvisuachua").ToString();
            frm.rTxt_mota.Text   = grV_hoadon.GetRowCellValue(grV_hoadon.FocusedRowHandle, "mota").ToString();

            frm.Show();
        }