I wanted to use this Accordion control on a page and so I specified the ContentTemplate and HeaderTemplate and gave it a DataTable as a DataSource and DataBound it. Nothing! No errors, no warnings, no display of any kind. After a few frustrating minutes of trying to solve it I asked buddy Google about it and it turned out that the Accordion control MUST receive a DataView as a DataSource and nothing else. Using datatable.DefaultView solved it.