Why aren't MVC Controllers fired in a Web API application?

Question

API

I am learning ASP.net MVC Framework.
I created an application from Web Api templates (it is the API that interests me now) according to a tutorial from Microsoft .
Now I'm trying to add standard MVC controllers to it and nothing comes out.
I created a HomeController class that inherited from Controller and put it in the Controllers folder.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using System.Web.Http;

namespace StopSalesApi.Controllers
{
    public class HomeController : Controller
    {
        //
        // GET: /Home/
        public String Index()
        {
            return "HelloWorld";
        }
  }
}

Previously added to the collection of routings, a route for non-Api controllers.

public static void Register(HttpConfiguration config)
        {
            // Web API routes
            config.MapHttpAttributeRoutes();

            config.Routes.MapHttpRoute(
                name: "DefaultApi",
                routeTemplate: "api/{controller}/{id}",
                defaults: new { id = RouteParameter.Optional }
            );

         // MVC routes
            config.Routes.MapHttpRoute(
                name: "Default",
                routeTemplate: "{controller}/{action}",
                defaults: new {controller = "Home", action = "Index"}
            );
        }

But the MVC Framework flatly refuses to see my Home controller. Other controllers that inherit from ApiController run, but Controller descendants do not.
Gives json error

{"Message":"Не удалось найти ресурс HTTP, соответствующий URI запроса \"http://localhost:9707/\".","MessageDetail":"Не удалось найти тип, соответствующий контроллеру \"Home\"."}

At the same time, it is worth changing the parent class of the Home type to ApiController and the framework begins to see it.
I have already created a full-fledged MVC application from templates in VS and checked the differences, copied the list of packages to my project, but nothing has changed.
I just can’t understand which setting is responsible for finding controllers?

Answer 1

Everything. Mastered at last.
In addition to using RouteTable.Routes instead of GlobalConfiguration.Configuration.Routes, you must also use the MapRoute() method instead of MapHttpRoute().

namespace StopSalesApi
{
    public class WebApiApplication : System.Web.HttpApplication
    {
        protected void Application_Start()
        {
            AreaRegistration.RegisterAllAreas();

            RouteTable.Routes.MapRoute(
                name: "Default",
                url: "{controller}/{action}",
                defaults: new { controller = "Home", action = "Index" });

            GlobalConfiguration.Configure(WebApiConfig.Register);
        }
    }
}

Answer 2

MVC controllers should be added to RouteTable.Routes (RouteTable.RouteCollection) , not GlobalConfiguration.Configuration.Routes (HttpConfiguration.HttpRouteCollection). These are different routes.
And there it will be

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