Dependency on a service layer with Ninject and MVC - asp.net-mvc

Question

I've got a problem with a bog standard three tier project using MVC that I'm trying to use Ninject with. I've got a MemberRepository:
public class MemberRepository : IMemberRepository{
public bool Save(Member member){
//saves member
}
}
I then have my Service Layer:
public class MemberService : IMemberService{
public bool Register(string email){
//Do Stuff & Populate Member Object
_repo.Save(member);
}
}
Given I'll be using Ninject what is the best way of me setting up my AccountController. Should I pass in the MemberService to the constructor like so:
public class AccountController : Controller
{
IMemberService _memberService;
public AccountController(IMemberService memberService)
{
_memberService = memberService;
}
}
Or pass in the repository:
public class AccountController : Controller
{
IMemberService _memberService;
public AccountController(IMemberRepository memberRepo)
{
_memberService = new MemberService(memberRepo);
}
}
Or Both?
I originally had just a repository (no service layer) but I've had to implement a service layer and I'm not sure how I'd handle the 'dependency' when registering the kernal in my NinjectWebCommon.cs file. Which was originally just this:
kernel.Bind<IMemberRepository>().To<SqlMemberRepository>();
But now I'm wondering if I need to register the IMemberService and have the repo as some kind of parameter.
:s Feeling kind of lost. Hope I'm making sense and someone can help out.

Answer 1

I've never used Ninject, I've been using Unity, but the same principles exist so hopefully this might help.
The service layer is the thing that is exposed to the controller - the controller needs to know nothing about the underlying repository. The flow is as follows, and each layer doesn't know about the layers above it:
Controller -> Service > Repository
So I would go with option 1, and then inject the repository into the constructor of the service.
public class MemberService : IMemberService {
private readonly IMemberRepository _repo;
[Inject]
public MemberService (IMemberRepository repo){
this._repo = repo;
}
public bool Register(string email){
//Do Stuff & Populate Member Object
_repo.Save(member);
}
}
and
public class AccountController : Controller
{
private readonly IMemberService _memberService;
[Inject]
public AccountController(IMemberService memberService)
{
_memberService = memberService;
}
}
That example obviously uses constructor injection but you can use property/field injection if you want instead. When you register your dependencies, you'll have to register both:
kernel.Bind<IMemberRepository>().To<SqlMemberRepository>();
kernel.Bind<IMemberService>().To<MemberService>();