public class AuthenAdminAttribute:FilterAttribute,IAuthorizationFilter

    {

        public void OnAuthenticationChallenge(AuthenticationChallengeContext filterContext)

        {

            //这个方法是在Action执行之后调用

        }

        public void OnAuthorization(AuthorizationContext filterContext)

        {

            //这个方法是在Action执行之前调用

            var user = filterContext.HttpContext.Session["userName"];

            if (user == null)

            {

                //filterConetext.HttpContext.Response.Redirect("/Login/index");

                var url = new UrlHelper(filterContext.RequestContext);

                var urls = url.Action("Index", "Login");

                filterContext.Result = new RedirectResult(urls);

            }

        }

    }

    [AuthenAdmin]

    public class HelloController : Controller

    {

        // GET: Hello

        public ActionResult Index()

        {

            return View();

        }

        public string welcome(string name,int id=1){

            return HttpUtility.HtmlEncode("hello "+name+":"+id);

        }

    }

方法二：

public class BaseController : Controller

    {

        protected override void OnActionExecuting(ActionExecutingContext filterContext)

        {

            if (HttpContext != null)

            {

                if (HttpContext.Session["userName"] != null)

                {

                }

                else

                {

                    filterContext.Result = new RedirectResult("/Login/Index");

                }

            }

            base.OnActionExecuting(filterContext);

        }

    }