Tiny Tip: Exporting to Excel from GridView inside UpdatePanel
This is a basic feature that most of todays application provide the most widly used implementation make use of the Response object to write to all the page which dosn't go well with ajax calls that concerns with only a portion of the page.
you can place the export button outside the girdview ofcourse but itn's that conveniant for all secenarions, however you can tell the updatepanel to do a semi full post back when specifit trigger is fired using the following:
<Triggers>
<asp:PostBackTrigger ControlID="btnExport" />
</Triggers>