ASP.NET MVC Route不起作用，为什么？

Question

我有这条路线：

routes.MapRoute(
    name: "ThreadList",
    url: "Forums/{category}/",
    defaults: new { controller = "Forums", action = "ThreadList" }
);

它与此链接不匹配：

http://localhost:11227/Forums/MyCategory

我犯了错误？