How to check if user is authorized inside Action

Question

Usually I protect my Actions with [Authorize] but this time I need to check if a user is authorized inside the action.

Eg

if(userIsAuthorized) {
    //do stuff
}
else {
    //return to login page
}

I believe I am using 'Forms Authentication'

This question is kind of similar to this but none of the answers given seemed to work.

EDIT: I have done some more digging- it seems if I breakpoint on an Action that has [Authorize], the User.Identity is set, but on Actions without it, the User.Identity is empty, even if I am logged in

Answer 1

If you just want to know if the user is logged in:

if (User.Identity.IsAuthenticated) { ... }

If you are trying to do anything role-specific:

if (User.IsInRole("Administrators")) { ... }

The User instance is a public property of the Controller class, so you always have access to it from a Controller you write. If no user is logged in you should have a GenericPrincipal for the User and a GenericIdentity for the User.Identity, so don't worry about checking for nulls.