private void ComboxMaCD_Load(object sender, EventArgs e) { BUSGiaoVien a = new BUSGiaoVien(); DataTable dt = a.MaCDDayCombobox(); dt.Columns.Add("macd", typeof(string)); dt.Dispose(); cbxMaChuyenDeTTDK.ValueMember = "macd"; cbxMaChuyenDeTTDK.DataSource = dt; cbxMaCDDiem.ValueMember = "macd"; cbxMaCDDiem.DataSource = dt; }