private void txtSNum_TextChanged(object sender, EventArgs e)  

       {            

　　　　txtSName.Enabled = false;

            this.txtSNum.AutoCompleteSource = AutoCompleteSource.CustomSource;

            this.txtSNum.AutoCompleteMode = AutoCompleteMode.Suggest;

            string sqy = "select SNUM,sname from  xhs where SClass123='"+cobGrade123.Text+"'";

            DataSet ds = sServer.GetDataSet1(sqy);

            for (int i = 0; i < dy.Tables[0].Rows.Count; i++)  

           {

                this.txtSNum.AutoCompleteCustomSource.Add(ds.Tables[0].Rows[i][0].ToString() + "|" + ds.Tables[0].Rows[i][1].ToString());

            }

        }