public void HienThiDanhSachDauSachTheoMaTheLoai(string ma) { DauSach_DTO s = new DauSach_DTO(); s.MaTheLoai = int.Parse(ma); DataTable dt = Sach_BUS.SelectSachLikeMaTheLoaiDanhSachSach(s); colTenSach.ValueMember = "MaDauSach"; colTenSach.DisplayMember = "TenDauSach"; colTenSach.DataSource = DauSach_BUS.SelectDauSachAll(); if (dt.Rows.Count == 0) { dgvSach.DataSource = Sach_BUS.SelectSachNull(); } dgvSach.DataSource = dt; }