求助：asp.net里fromview控件问题

fromview里已绑定好数据源,如： 我要改变aa的值时重新加载
        <th>
           <asp:Label ID="lblbb" runat="server" Text='bb'></asp:Label>
        </th> text的值
如： Text='bb' 改成 Text =‘cc’
应该用fromview控件的那个事件啊？？示例代码如下：
<asp:FormView ID="frmRecordView" runat="server" DataSourceID="objRecordView" DataKeyNames="Machine_output_id"
            CssClass="FormViewCss" ondatabound="frmRecordView_DataBound">
  <EditItemTemplate>  </EditItemTemplate>
  <InsertItemTemplate>
    <Table>
      <tr>
        <th>
           <asp:Label ID="lblaa runat="server" Text='aa'></asp:Label>
        </th>
        <td>
           <asp:TextBox ID="txtaa" Text='<%# Bind("aa") %>' runat="server"></asp:TextBox>
        </td>
        <th>
           <asp:Label ID="lblbb" runat="server" Text='bb'></asp:Label>
        </th>
        <td>
           <asp:TextBox ID="txtbb" Text='<%# Bind("bb") %>' runat="server"></asp:TextBox>
        </td>
      </tr>
    </Table>
  </InsertItemTemplate>
  <ItemTemplate>  </ItemTemplate>
</asp:FormView>