asp.net怎样实现asp中的循环????帮帮我,看看错在那里????

DataSet ds = new DataSet();
            OleDbCommand cm = new OleDbCommand();
            cm.CommandText = "select * from topic";
            OleDbDataAdapter Adapter = new OleDbDataAdapter();
            Adapter.SelectCommand = cm;
            Adapter.Fill(ds);
             if (ds.Tables.Rows[0][0] > 0)
            {
                Datalist1.DataSource = ds.Tables[0].DefaultView;
                Datalist1.DataBind();
                
                DataSet ds1=new DataSet();
                OleDbCommand cm1=new OleDbCommand();
                cm1.CommandText="select * from message where id=" + ds.Tables[0].Rows[0][0];
                OleDbDataAdapter Adapter1 = new OleDbDataAdapter();
                Adapter.SelectCommand = cm1;
                Adapter.Fill(ds1);
                if (ds1.Tables.Rows[0][0]>0)
                {
                    Datalist2.DataSource = ds1.Tables[0].DefaultView;
                    Datalist2.DataBind();
                }            }
            else
            {
                Response.Write("<script>alert('gggggggggg')</script>");
            }