private void btMonHoc_Search_Click(object sender, EventArgs e) { string text = txbSearch.Text; if (text == "") { return; } BUS_MonHoc busMonHoc = new BUS_MonHoc(); EC_MonHoc MonHoc1 = busMonHoc.Select_ByPrimaryKey(text); List <EC_MonHoc> listResult = new List <EC_MonHoc>(); if (MonHoc1 != null) { listResult.Add(MonHoc1); } List <EC_MonHoc> listMonHoc2 = busMonHoc.SelectByFields("Ten_MonHoc", text); foreach (EC_MonHoc ec in listMonHoc2) { listResult.Add(ec); } dgSearchResult.Rows.Clear(); foreach (EC_MonHoc ec in listResult) { dgSearchResult.Rows.Add(ec.Ma_MonHoc, ec.Ten_MonHoc, ec.Lop, null); } }