Session超时问题(AOP 过滤器)

public class TimeoutAttribute : ActionFilterAttribute
    {
        public override void OnActionExecuting(ActionExecutingContext filterContext)
        {
            HttpContextBase context = filterContext.HttpContext;
            HttpResponseBase response = filterContext.HttpContext.Response;
            HttpRequestBase request = filterContext.HttpContext.Request;
            if (context.Session["User"] == null)
            {
                if (request.IsAjaxRequest())
                    response.Status = "401 Session Timeout";
                else
                    response.Redirect("/Home/Login");//返回登录页
                filterContext.Result = new HttpUnauthorizedResult();//这一行保证不再执行Action的代码
                response.End();//必须加上这句，否则返回前台status始终是200
                return;
            }
            base.OnActionExecuting(filterContext);
        }
    }