gridview edititemtemplate dropdownlist问题

        protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
        {          
            if((e.Row.RowState   &   DataControlRowState.Edit)   !=   0 && e.Row.RowType == DataControlRowType.DataRow)
            {
                Label lb1 = (Label)e.Row.FindControl("Label3");
                DropDownList  ddl = (DropDownList)e.Row.FindControl("DropDownList1");

                ListItem li = new ListItem();
                li.Value = "1";
                li.Text = "哈";
                ddl.Items.Add(li);
            }
        }