public class CheckLoginAttribute : ActionFilterAttribute    {        public CheckLoginAttribute()        {         }        public override void OnActionExecuting(ActionExecutingContext filterContext)        {            if (filterContext.HttpContext.Session["User"] == null)            {                filterContext.Result = new RedirectResult("/Account/LogOn");                return;            }            base.OnActionExecuting(filterContext);        }    }

public class HomeController : Controller    {        public ActionResult Index()        {            ViewBag.Message = "Welcome to ASP.NET MVC!";            return View();        }        [CheckLogin]        public ActionResult About()        {            return View();        }    }

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