特定演员表无效组合c＃

Question

请帮我选择组合框列表表格数据库

 void fillCombo2()
    {
        try
        {
            cc.con = new SqlConnection(cs.DBConn);
            cc.con.Open();
            cc.cmd = new SqlCommand("Select kod_jawatan from jawatan", cc.con);
            cc.rdr = cc.cmd.ExecuteReader(CommandBehavior.CloseConnection);
            while (cc.rdr.Read() == true)
            {
                int kID = cc.rdr.GetInt32(0);
                comboBox1.Items.Add(kID);
                //comboBox1_SelectedIndexChanged will change the index to textbox 



            }
            cc.con.Close();
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
        }
    }

但我收到以下异常：指定演员无效。