Problem about UpdatePanel Triggers with SelectedNodeChanged event

Hi,everyone

I have a problem when use UpdatePanel , when debugging ,cannot run ,but no error tips,who can help me .Thanks very much!

<asp:UpdatePanel ID="AjaxMapPanel" runat="server">
<Triggers>

<asp:AsyncPostBackTrigger ControlID="DataTreeView" EventName="SelectedNodeChanged" />
</Triggers>
<ContentTemplate>
<asp:ImageButton ID="imgMap" runat="server" Height="672px" Width="864px" BorderWidth="1px">
</asp:ImageButton>
</ContentTemplate>

</asp:UpdatePanel>

Hi,

Would you mind elaborating it?

What happened when you tried to debug it?

Can you successfully build it?

Or please show me a simple repro.