Question

RedirectToAction is protected, and we can use it only inside actions. But if I want to redirect in a filter?

public class IsGuestAttribute: ActionFilterAttribute {     public override void OnActionExecuting(ActionExecutingContext filterContext)     {         if (!Ctx.User.IsGuest)              filterContext.Result = (filterContext.Controller as Controller)                 .RedirectToAction('Index', 'Home');     } } 

Answer 1

RedirectToAction is just a helper method to construct a RedirectToRouteResult(), so what you do is simply create a new RedirectToRouteResult() passing along a RouteValueDictionary() with values for your action.

Complete sample based on code from @Domenic in the comment below:

public class IsGuestAttribute: ActionFilterAttribute {     public override void OnActionExecuting(ActionExecutingContext filterContext)     {         if (!Ctx.User.IsGuest)          {             filterContext.Result = new RedirectToRouteResult(                 new RouteValueDictionary                  {                      { 'controller', 'Home' },                      { 'action', 'Index' }                  });         }     } }