How to intercept clicking of a built-in Office Ribbon control

Question

I\'m wondering if it\'s possible to detect when a user has clicked the Header/Footer button in Excel so I can show some custom header/footer related ribbon controls on my add-in

Answer 1

One way I've discovered that worked was to use the <commands> section in the Ribbon XML (which I didn't know existed.) Apparently this mechanism allows you to re-purpose actions intrinsic to Excel but beware that not all controls support re-purposing the onAction callback)

<?xml version="1.0" encoding="UTF-8"?>
<customUI onLoad="Ribbon_Load" xmlns="http://schemas.microsoft.com/office/2006/01/customui">
    <commands>
        <command idMso="HeaderFooterInsert" onAction="testHeaderFooter"/>
    </commands>
  <ribbon>
    <tabs>...

along with the associated event handler:

    public void testHeaderFooter(Office.IRibbonControl control, bool cancelDefault)
    {
        MessageBox.Show("Testing.");
        cancelDefault = false;
    }

This link was very helpful:

http://social.msdn.microsoft.com/Forums/office/en-US/e1a60d16-053e-4697-b17c-b22d602f0400/intercept-the-onaction-event-of-a-gallery-element-of-excel-2007-ui-ribbon?forum=vsto