01.private void parties()
02.{
03.string sql_parties = "SELECT * FROM tb_parties ORDER BY parties_id ASC";
04.conn_manage.dbconn_manage.Open();
05.DataTable dt_parties = new DataTable();
06.SqlDataAdapter adap_manage = new SqlDataAdapter(sql_parties,conn_manage.dbconn_manage);
07.adap_manage.Fill(dt_parties);
08.
09.if (dt_parties.Rows.Count > 0)
10.{
11.ddl_parties_id.DataSource = dt_parties;
12.ddl_parties_id.DataTextField = "parties_name";
13.ddl_parties_id.DataValueField = "parties_id";
14.ddl_parties_id.DataBind();
15.}
16.ddl_parties_id.Items.Add("");
17.ddl_parties_id.SelectedIndex = ddl_parties_id.Items.IndexOf(ddl_parties_id.Items.FindByValue(""))
18.conn_manage.dbconn_manage.Close();
19.}
ขอบคุณมากเลยครับที่ให้คำแนะนำ 
