MVC过滤器处理Session过期

 public class CheckSession: ActionFilterAttribute
    {
        public override void OnActionExecuting(ActionExecutingContext filterContext)
        {
            object[] attrs = filterContext.ActionDescriptor.GetCustomAttributes(typeof(NoFilter), true);
            if (attrs.Length == 1){}
            else { 
                if (filterContext.HttpContext.Session != null)
                {
                    if (filterContext.HttpContext.Session.IsNewSession)
                    {
                        var loginUser = filterContext.HttpContext.Session["User"];


                        if (loginUser == null)
                        {
                            if (!filterContext.HttpContext.Request.IsAjaxRequest())
                            {
                                filterContext.Result = new RedirectResult("/GY_User/LoginIndex");
                            }
                            else
                            {
                                filterContext.Result = new JsonResult
                                {
                                    Data = new
                                    {
                                        Success = false,
                                        Message = string.Empty,
                                        Redirect = "/GY_User/LoginIndex"
                                    }
                                };
                            }
                        }
                    }
                }
            }
            // base.OnActionExecuting(filterContext);
        }
    }

   //不想使用全局过滤器可使用此标签
    public class NoFilter:Attribute
    {
        public NoFilter() { }
    }

public static void RegisterGlobalFilters(GlobalFilterCollection filters)
        {
           // filters.Add(new HandleErrorAttribute());
            filters.Add(new CheckSession());
        }

protected void Application_Start()
        {
            AreaRegistration.RegisterAllAreas();
            RouteConfig.RegisterRoutes(RouteTable.Routes);
            FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
        }

Session["User"] = jsonData.data;
 Session.Timeout = 3;