c# combox繫結oracle查詢的資料集（列)

private void Form1_Load(object sender, EventArgs e)
        {

            OracleConnection con1 = new OracleConnection("Data Source=orcl;User id=scott; Password=system;");//oracleconnection類隸屬於名稱空間system.data.oracleclient
            
           
            OracleCommand oc1 = new OracleCommand("select loc as newloc  from dept", con1);
            OracleDataAdapter da = new OracleDataAdapter(oc1);
            DataSet ds1 = new DataSet();
            oda.Fill(ds1);

            //dataGridView1.DataSource = ds1.Tables[0];

            ////統計出列表中記錄條數 tables.rows.count
            //this.Text = ds1.Tables[0].Rows.Count.ToString();

            //for (int i=0; i < ds1.Tables[0].Rows.Count; i++)
            //{
            //    //向combox新增子項items.add,dataset.tables.rows[行索引][列名字],此列名字對應oraclecommand中sql的列名
            //    comboBox1.Items.Add(ds1.Tables[0].Rows[i]["newloc"]);
            //}

            //comboBox1.DataSource = ds1.Tables[0].Columns["newloc"];
            //combox繫結資料庫表查詢資料集不用定位到每個列，和操作datagridview一樣，定位到tables即可
            comboBox1.DataSource = ds1.Tables[0];
            //displaymember是展現給客戶看的
            comboBox1.DisplayMember = "居住地";
            //valuemember為真正資料庫中的列（或者sql的列或別名)
            comboBox1.ValueMember = "newloc";
        }