private void btnLuu_Click(object sender, EventArgs e)
        {
            frmHoaDonBanHang frm = frmHoaDonBanHang.Instance;

            row.BeginEdit();
            row["GiaBan"]    = txtGiaBan.Text.Trim();
            row["ThanhTien"] = decimal.Parse(txtGiaBan.Text.Trim()) * (int)row["SoLuong"] - (((int)row["ChietKhau"] * (int)row["SoLuong"] * decimal.Parse(txtGiaBan.Text.Trim())) / 100);
            row.EndEdit();

            frm.DtCurrHoaDon.AcceptChanges();
            frm.DgvChiTietHoaDonHienTai_LoadData();

            this.Close();
        }
        private void btnLuu_Click(object sender, EventArgs e)
        {
            frmHoaDonBanHang frm = frmHoaDonBanHang.Instance;

            row.BeginEdit();
            row["ChietKhau"] = nudCK.Value;
            row["ThanhTien"] = (decimal)(thanhTien);
            row.EndEdit();

            frm.DtCurrHoaDon.AcceptChanges();
            frm.DgvChiTietHoaDonHienTai_LoadData();

            this.Close();
        }
        private void btnLuu_Click(object sender, EventArgs e)
        {
            frmHoaDonBanHang frm  = frmHoaDonBanHang.Instance;
            frmDatHangNCC    frm1 = frmDatHangNCC.Instance;

            row.BeginEdit();
            row["SoLuong"] = nudSoLuong.Value;
            if (state == 1)// ban hang
            {
                // kiem tra so luong
                if (nudSoLuong.Value > luongTon)
                {
                    MessageBox.Show($"Mặt hàng \"{row["MaSP"].ToString()} - {row["TenSP"].ToString()}\" không đủ số lượng, trong kho chỉ còn {luongTon}");
                    return;
                }
                row["ThanhTien"] = (nudSoLuong.Value) * (decimal)row["GiaBan"] - (((int)row["ChietKhau"] * (decimal)row["GiaBan"] * nudSoLuong.Value) / 100);

                // giam so luong sp
                dbSanPham.UpdateProductAmount(row["MaSP"].ToString(), (-1) * ((int)nudSoLuong.Value - currsl));
            }
            else
            {
                row["ThanhTien"] = (nudSoLuong.Value) * (decimal)row["GiaMua"];
                // tang so luong sp
                dbSanPham.UpdateProductAmount(row["MaSP"].ToString(), (int)nudSoLuong.Value - currsl);
            }
            row.EndEdit();

            if (state == 1)
            {
                frm.DtCurrHoaDon.AcceptChanges();
                frm.DgvChiTietHoaDonHienTai_LoadData();
                frm.RefreshDgvDanhMucSanPham(row["MaSP"].ToString());
            }
            else
            {
                frm1.DtCurrCTHopDong.AcceptChanges();
                frm1.DgvChiTietHopDong_LoadData();
            }

            this.Close();
        }