private void SuaSachTrongKho_Load(object sender, EventArgs e) { Class.XuLyThuVien KiemTra = new Class.XuLyThuVien(); Class.Sach Book = KiemTra.InfoSach(MaSach_FormMain); lblMaSach.Text = Book.MaSach; txtTenSach.Text = Book.TenSach; UpDownSL.Value = Book.SoLuong; }