MVC设定默认路由为指定的Area下的某个action

public static void RegisterRoutes(RouteCollection routes)
    {
      routes.IgnoreRoute("{resource}.axd/{*pathInfo}");
      routes.MapRoute(
        name: "Default",
        url: "{controller}/{action}/{id}",
        defaults: new { controller = "WebShow", action = "List", id = UrlParameter.Optional }
      );     
    }

public class AdminAreaRegistration : AreaRegistration
  {
    public override string AreaName
    {
      get
      {
        return "Admin";
      }
    }
    public override void RegisterArea(AreaRegistrationContext context)
    {
      context.MapRoute(
        "Admin_default",
        "Admin/{controller}/{action}/{id}",
        new { controller = "Login", action = "Index", id = UrlParameter.Optional } //默认路径是Login控制器，和Index action
      );
    }
  }

public static void RegisterRoutes(RouteCollection routes)
    {
      routes.IgnoreRoute("{resource}.axd/{*pathInfo}");
      routes.MapRoute(
         "Default",
        "{controller}/{action}/{id}",
        new { controller = "Login", action = "Index", id = UrlParameter.Optional }, //这里要和Admin块下的默认控制器和action一样
        new[] { "GTA.CMS.Site.Web.Areas.Admin.LoginController" }// 这个是你控制器所在命名空间
      ).DataTokens.Add("area","Admin");     
    }