private void btThem_Click(object sender, EventArgs e) { Luat l = new Luat(); List <MenhDe> veTrai = new List <MenhDe>(); MenhDe vePhai = new MenhDe(); // Vetrai for (int i = 0; i < clbVeTrai.CheckedItems.Count; i++) { MenhDe m = new MenhDe(); String ma = clbVeTrai.CheckedItems[i].ToString().Split(':')[0]; m = m.TimTheoMa(int.Parse(ma)); veTrai.Add(m); } // VePhai vePhai = vePhai.TimTheoMa(int.Parse(cbVePhai.SelectedValue.ToString())); l.Them(tbTen.Text, tbMoTa.Text, veTrai, vePhai); LoadLuat(); btLamMoi_Click(sender, e); }