[C#] combobox显示数据库内容

SqlConnection Conn = //到sqlsever的连接          
            string Sql = "SELECT sno+'- '+sname as result FROM student where profession='" + comboBox1.SelectedItem + "'";
            DataSet Ds = new DataSet();  
            SqlDataAdapter Da = new SqlDataAdapter(Sql, Conn);  
            Da.Fill(Ds, "student");  
            comboBox2.DataSource = Ds.Tables["student"];  
            comboBox2.DisplayMember = "result";  

            Conn.Close();