MVC验证session是否过期，在每个action执行之前验证

        protected override void OnActionExecuting(ActionExecutingContext filterContext)

        {

            base.OnActionExecuting(filterContext);

            if (Session["wx_s_user"] == null)

            {

                filterContext.Result = new RedirectToRouteResult(new RouteValueDictionary(new { controller = "Login", action = "index" }));

            }

}