N Layer - Dependency Injection - Net Core

Question

I'm building a solution architecture in ASP.NET Core.

I reference repositories in the web project for declare dependency injection in the ConfigureServices(), is it ok for you?

I think that ideal would be only reference the services project because controllers only should use services but not repositories.

I have these projects:

1. Web App (ASP.NET Core) - reference all projects.

   public void ConfigureServices(IServiceCollection services)
   {
        services.AddMvc();
        services.AddTransient<IEventsService, EventsService>();
        services.AddTransient<IEventsRepository, EventsSqlRepository>();
   }
   
   public class EventsController : Controller
   {
        private readonly IEventsService _eventsService;
   
        public EventsController(IEventsService eventsService)
        {
             _eventsService = eventsService;
        }
   }
   

2. Business (class library - .NET standard)

   Folder IServices 
        IEventsService
   
   Folder Services
   
   public class EventsService : IEventsService
   {
       private readonly IEventsRepository _eventsRepository;
   
       public EventsService(IEventsRepository eventsRepository)
       {
            _eventsRepository = eventsRepository;
       }
   }  
   

3. IRepository (class library - .NET Standard)

   • IEventsRepository

4. Repository (class library - .NET Standard)

   • Access to BD using E.F.

     public class EventsSqlRepository : BaseRepository, IEventsRepository
     {
     }
     

5. Utils (class library - .NET Standard)

6. Entities (class library - .NET Standard)

   • Mapped from BD E.F

Thanks very much !

Answer 1

Your solution looks fine. The part where application dependencies are registered is called the composition root and it's the only place in your application where all your dependencies should be registered. Even though it's physically placed in the web project part of you app, it's logically a standalone part of your application. You can read more about it here: http://blog.ploeh.dk/2011/07/28/CompositionRoot/