private void btnXoa_Click(object sender, EventArgs e)
        {
            if (DialogResult.Yes == MessageBox.Show("Xoá chứ?", "Thông báo", MessageBoxButtons.YesNo))
            {
                DBO.tb_ChiTietHoaDonNhapDBO obj = new DBO.tb_ChiTietHoaDonNhapDBO
                {
                    DonGia       = Convert.ToDouble(txtDG.Text),
                    MaCTHDN      = txtMaCTHD.Text,
                    SoLuong      = Convert.ToInt16(txtSL.Text),
                    MaHoaDonNhap = txtMaHD.Text,
                    MaMatHang    = cbMaHang.Text
                };
                BLL.tb_ChiTietHoaDonNhapBLL.xoa(obj);

                btnTaiLai_Click(sender, e);
            }
        }
        private void btnSua_Click(object sender, EventArgs e)
        {
            DBO.tb_ChiTietHoaDonNhapDBO obj = new DBO.tb_ChiTietHoaDonNhapDBO
            {
                DonGia       = Convert.ToDouble(txtDG.Text),
                MaCTHDN      = txtMaCTHD.Text,
                SoLuong      = Convert.ToInt16(txtSL.Text),
                MaHoaDonNhap = txtMaHD.Text,
                MaMatHang    = cbMaHang.Text
            };
            BLL.tb_ChiTietHoaDonNhapBLL.xoa(obj);
            BLL.tb_ChiTietHoaDonNhapBLL.them(obj);

            btnTaiLai_Click(sender, e);

            //if (BLL.tb_ChiTietHoaDonNhapBLL.kiemTraTonTai(obj) == 0)
            //    BLL.tb_ChiTietHoaDonNhapBLL.them(obj);
            //else
            //    MessageBox.Show("Đã trùng");
        }