ASP.NET MVC无法理解路由

Question

我已经得到了这个小组项目，我试图理解并且在路线如何工作方面遇到问题。困扰我的第一件事是为什么在RouteConfig.cs文件中注册了一些路由，而在Global.asax中注册了其他路由？为什么在RouteConfig.cs中使用routes.Add，与routes.MapRoute相比它做了什么？

这里的RouteConfig.cs：

public class RouteConfig
{
    public static void RegisterRoutes(RouteCollection routes)
    {
        routes.Add(new LowercaseDashedRoute("{controller}/{action}/{id}",
            new RouteValueDictionary(
                new { controller = "Home", action = "Index", id = UrlParameter.Optional }),
                new DashedRouteHandler()
            )
        );

    }

这是Global.asax：

 public class MvcApplication : System.Web.HttpApplication
{
    protected void Application_Start()
    {
        AreaRegistration.RegisterAllAreas();
        FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
        RouteConfig.RegisterRoutes(RouteTable.Routes);
        BundleConfig.RegisterBundles(BundleTable.Bundles);
    }

    public static void RegisterRoutes(RouteCollection routes)
    {
        routes.MapRoute("SpecificRouteforHomeController", "{action}/{id}", new { controller = "Home", action = "Index", id = "" });

        // default route  any defalt you want
        routes.MapRoute("Default", "{controller}/{action}/{id}", new { controller = "Services", action = "Index", id = "" });
    }