ASP MVC Web API endpoint returning 404

Question

I am learning Angular 2 and trying to get it running on an ASP MVC setup. I am following this very excellent guide: https://www.codeproject.com/Articles/1181888/Angular-in-ASP-NET-MVC-Web-API-Part

I modified it very slightly. The original is supposed to manipulate a list of names obtained from the database through the API endpoint api/userapi . I changed it up so that it becomes a list of posts (like for a blog or something) from the endpoint api/postapi . The Angular part of the project is working so far. It's the ASP.NET part of it that's not working properly.

Looking at the configuration of the original project (which I downloaded from that link and tested in Visual Studio 2017 to be fine) and comparing it to my experiment, for the life of me I could not spot where I may have misconfigured it.

What could be the problem here? Here's my code for the Web API part:

Global.asax.cs

using System.Web.Http;
using System.Web.Mvc;
using System.Web.Optimization;
using System.Web.Routing;

namespace WebAPI
{
    public class WebApiApplication : System.Web.HttpApplication
    {
        protected void Application_Start()
        {
            AreaRegistration.RegisterAllAreas();
            GlobalConfiguration.Configure(WebApiConfig.Register);
            FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
            RouteConfig.RegisterRoutes(RouteTable.Routes);
            BundleConfig.RegisterBundles(BundleTable.Bundles);
        }
    }
}

RouteConfig.cs

using System.Web.Mvc;
using System.Web.Routing;

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

            routes.MapRoute(
                name: "Default",
                url: "{*anything}", // I am suspicious of this line but changing it doesn't fix it
                defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional }
            );
        }
    }

WebApiConfig.cs

using System.Net.Http.Headers;
using System.Web.Http;

namespace WebAPI
{
    public static class WebApiConfig
    {
        public static void Register(HttpConfiguration config)
        {
            // Web API configuration and services

            // Output as JSON instead of XML
            config.Formatters.JsonFormatter.SupportedMediaTypes
                .Add(new MediaTypeHeaderValue("application/octet-stream"));

            // Web API routes
            config.MapHttpAttributeRoutes();

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

PostsAPIController.cs

using WebAPI.Models;
using System.Data.Entity;
using System.Linq;
using System.Net.Http;
using System.Web.Http;

namespace WebAPI.Controllers
{
    [RoutePrefix("api/postapi")] //this did not help either
    public class PostsAPIController : BaseAPIController
    {
        public HttpResponseMessage Get()
        {
            return ToJson(_db.TWebSitePostsSet.AsEnumerable());
        }

        public HttpResponseMessage Post([FromBody]TWebSitePosts value)
        {
            _db.TWebSitePostsSet.Add(value);
            return ToJson(_db.SaveChanges());
        }

        public HttpResponseMessage Put(int id, [FromBody]TWebSitePosts value)
        {
            _db.Entry(value).State = EntityState.Modified;
            return ToJson(_db.SaveChanges());
        }

        public HttpResponseMessage Delete(int id)
        {
            _db.TWebSitePostsSet.Remove(_db.TWebSitePostsSet.FirstOrDefault(x => x.PostId == id));
            return ToJson(_db.SaveChanges());
        }
    }
}

Answer 1

Change this code [RoutePrefix("api/postapi")] to [Route("api/postapi")] and see if that makes a difference.
And check out this page. Attribute routing webapi-2