MVC过滤器

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using System.Web.Routing;

namespace StudentManage.Filter
{
 public class MessageExceptionFilter : FilterAttribute, IExceptionFilter, IActionFilter
 {
  public void OnException(ExceptionContext filterContext)
  {

  }

  public  void OnActionExecuted(ActionExecutedContext filterContext)
  {
           
  }

  public  void  OnActionExecuting(ActionExecutingContext filterContext)
  {
   if(filterContext.HttpContext.Session["UserName"]==null)
   {
    //UrlHelper helper = new UrlHelper(filterContext.RequestContext, RouteTable.Routes);
    //filterContext.Result = new RedirectResult(helper.RouteUrl("Default"));

    filterContext.HttpContext.Response.Redirect("/Account/LogOn");//重定向到登陆页
   }
  }
 }
}