Redirect to another page when user is not authorized in asp.net mvc3

Question

I\'ve read

How to easily redirect if not authenticated in MVC 3? and Redirect to AccessDenied page when user is not authorized but the link from an answer (means h

Answer 1

I like Mark's Answer,
but I don't want to change all of my action attributes
from [Authorize] to [CustomAuthorize]

I edit Login() action on AccountController
and check Request.IsAuthenticated before show view
I think, if the authenticated user go to /Account/Logon,
I will redirect to /Error/AccessDenied.

    [AllowAnonymous]
    public ActionResult Login(string returnUrl)
    {
        if (Request.IsAuthenticated)
        {
            return RedirectToAction("AccessDenied", "Error");
        }

        ViewBag.ReturnUrl = returnUrl;

        return View();
    }