ASP.NET MVC Controller SubFolder

我正在使用ASP.NET MVC并尝试创建一个控制器子文件夹.我查看了这个网站上的其他帖子并尝试了我在网上找到的内容,但它仍然遇到了这个问题:

HTTP 404. The resource you are looking for (or one of its dependencies) could have been removed, had its name changed, or is temporarily unavailable.  Please review the following URL and make sure that it is spelled correctly.

下面的屏幕截图是我在控制器文件夹中创建的子文件夹.

这是我的View文件夹的屏幕截图.

这是我在RouteConfig.cs文件中尝试的内容

public static void RegisterRoutes(RouteCollection routes)
{
    routes.IgnoreRoute("{resource}.axd/{*pathInfo}");

    routes.MapRoute(
        name: "Default",
        url: "{controller}/{action}/{id}",
        defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional }
    );

    routes.MapRoute(
        name: "AdminSubForder",
        url: "admin/{controller}/{action}/{id}",
        defaults: new { controller = "HomeAdmin", action = "Index", id = UrlParameter.Optional }
    );
}

但我的子文件夹仍然无法正常工作.我在这做错了什么？