Filter过滤的2种方式

1.新建一个过滤器，继承ActionFilterAttribute，然后重写

public class DemoFilterAttribute:ActionFilterAttribute
    {
        //在Action执行之前执行
        public override void OnActionExecuting(ActionExecutingContext filterContext)
        {
            filterContext.HttpContext.Response.Write("action之前");
            base.OnActionExecuting(filterContext);
        }
        //在Action执行之后执行
        public override void OnActionExecuted(ActionExecutedContext filterContext)
        {
            filterContext.HttpContext.Response.Write("action之后");
            base.OnActionExecuted(filterContext);
        }
        //在Result执行之前执行
        public override void OnResultExecuting(ResultExecutingContext filterContext)
        {
            filterContext.HttpContext.Response.Write("Result之前");
            base.OnResultExecuting(filterContext);
        }
        //在Reuslt执行之后执行（就是方法中的代码走完之后）
        public override void OnResultExecuted(ResultExecutedContext filterContext)
        {
            filterContext.HttpContext.Response.Write("Result之后");
            base.OnResultExecuted(filterContext);
        }
    }

然后在要进行过滤的控制器或方法上打上该特性标签

public class AjaxDemoController : Controller
    {
        EFDemo.OAEntities db = new EFDemo.OAEntities();
        // GET: AjaxDemo
        [DemoFilter]
        public ActionResult Index()
        {
            return View();
        }
    }

2.新建一个控制器，在控制器内重写OnActionExecuting方法，然后让要进行过滤的控制器继承它

    public class BaseController : Controller
    {
        /// <summary>
        /// 在执行控制器中方法前先执行该方法
        /// </summary>
        /// <param name="filterContext"></param>
        protected override void OnActionExecuting(ActionExecutingContext filterContext)
        {
            base.OnActionExecuting(filterContext);
            if (Session["userInfo"] == null)
            {
                filterContext.HttpContext.Response.Redirect("/Login/Index");
            }
        }
    }

public class UserInfoController :BaseController //Controller
    {
    }