ASP.net Web Forms with Routing - How to Get the name of the Physical File Being Executed

Scenario.
Have ASPX web forms page.  The MasterPage associated with the ASPX page has a common ASCX control in it.  The ASCX control needs to determine the name of the physical file being executed. This use to be simple, but we recently implemented ASP.net routing and are having difficulty retrieving the name of the physical file being executed from a control in the master page.  For example:
http://www.somewhere.com/somedirectory/xyz.aspx  - pre routing it was easy to get xyz.aspx as the name of the file executing www.somewhere.com/somedirectory/xyz/p1/p2 - routing sends this to physical file xyz.aspx to execute In a usercontrol in the masterpage associated with xyz.aspx we want know that xyz.aspx is the file being executed.
Any suggestions would be appreciated.
Thanks
P.S. not asking h ...