Principal Permission

Question

I worte a method with PrincipalPermissionAttrubute then i run this method but i get an exception - security exception.

It happen cause i dont know who is the principal that running. I try to get the current principal by

Thread.GetCurrntPrincipal()

but i have a casting problem.

My question is how i know the principal who running and then i know what to define in name and role in PrincipalPermissionAttribut

Thanks a lot..