Question

I’m building an MVC3 application using the Entity Framework. In the application my controllers talk to a service layer. One of the controllers is a TournamentController which uses the TournamentService. This service has some standard methods such as CreateTournament, UpdateTournament etc.

When I want to insert a new tournament I want the view to have a dropdownlist of possible sports for which the tournament can be organised. So in the TournamentController's Create method I fill the ViewBag.Sports with a list of possible sports. Now to obtain this list of sports I use _tournamentService.GetAllSports(). In this GetAllSports() method of the TournamentService I want to create an instance of the SportService so I can ‘forward’ the question to the right service.

All services use dependency injection in the constructor to inject their own repository, like so:

private ITournamentRepository _repo;

public TournamentService(ITournamentRepository repo) {
    _repo = repo;
}

My GetAllSports() method in the TournamentService looks like this:

public IEnumerable<Sport> GetAllSports() {
    ISportService sportService = new SportService();
    return sportService.GetSports();
}

The problem is that by calling the new SportService() it expects me to hand it an ISportRepository like in the TournamentService, where ninject creates the TournamentRepository. Now I could do the following:

public IEnumerable<Sport> GetAllSports() {
    ISportService sportService = new SportService(new SportRepository());
    return sportService.GetSports();
}

But the problem with that is that each repository expects an IContext, which is normally handled by ninject as well. Furthermore, I don’t want two separate contexts to be instantiated.

A possible solution I found myself is to do this:

private ITournamentRepository _repo;
private ISportService _sportService;

public TournamentService(ITournamentRepository repo, ISportService sportService) {
    _repo = repo;
    _sportService = sportService
}

But there’s only one method in my TournamentService class that would actually use the _sportService so I figure this is a bit overkill to make it a class attribute.

Answer 1

Keep it simple, inject ISportService to your controller and call sportService.GetSports() directly from the controller!