.NET MVC Dependency Injection with Ninject

asp.net, asp.net-mvc, c#, dependency-injection, ninject

Solution

From the package manager console run this command:

Install-package Ninject.MVC3

This will add a class to `App_Start/NinjectWebCommon.cs`

If you look near the bottom there is a RegisterServices method.

You simply add the code from your question there i.e.

    private static void RegisterServices(IKernel kernel)
    {
      kernel.Bind<IUnitOfWork>().To<UnitOfWork>();
      kernel.Bind<ITownService>().To<TownService>();
      kernel.Bind<IRestaurantService>().To<RestaurantService>();
      kernel.Bind<IFoodService>().To<TownService>();
    }

Problem

I've just started programming in .NET and I'm having some problems with implementing `dependency injection (using Ninject)`. I'm creating some sort of catering application where user can browse towns, in towns browse restaurants and in restaurants browse food. I'm using UnitOfWork and repository pattern where for example I access town by id like this: ``` _unitOfWork.TownRepository.GetByID(id); ``` Now I started implementing services into application and I have encountered need for `dependency injection`. I have created `ITownService`, `IRestaurantService` and `IFoodService` (since I've `TownRepository`, `RestaurantRepository` and `FoodRepository` in my `UnitOfWork`). Sample look of TownService: ``` public class TownService : ITownService { // initialize UnitOfWork private IUnitOfWork _unitOfWork; public TownService() : this(new UnitOfWork()) { } public TownService(IUnitOfWork unitOfWork) { _unitOfWork = unitOfWork; } public Town GetByID(object id) { return _unitOfWork.TownRepository.GetByID(id); } public IEnumerable<Town> GetAll() { return _unitOfWork.TownRepository.Get(); } public bool Insert(Town town) { // validation logic if (!ValidateTown(town)) return false; try { _unitOfWork.TownRepository.Insert(town); _unitOfWork.Save(); } catch { return false; } return true; } public bool Delete(object id) { try { _unitOfWork.TownRepository.Delete(id); _unitOfWork.Save(); } catch { return false; } return true; } public bool Update(Town townToUpdate) { // validation logic if (!ValidateTown(townToUpdate)) return false; try { _unitOfWork.TownRepository.Update(townToUpdate); _unitOfWork.Save(); } catch { return false; } return true; } } ``` I haven't implemented `FoodService` and `RestaurantService` yet, but they should be similar with of course some additinal methods exepct this that I have. For example in `RestaurantService` I might have `public Restaurant GetRestaurantsInTown(Town town){}` or something like that. I hope that you got the feel of application a bit. Now lets back to `Ninject`. In my `TownController` I would have something like this: ``` public class TownController : Controller { private ITownService _townService; public TownController(ITownService townService) { _townService = townService; } } ``` Similar would be for `RestaurantController` and `FoodController` of course just constructor injecting. How do I use `Ninject` in such example? Do I need some global `IService` and not `ITownService`, `IRestaurantService` and `IFoodService` which I'd inherid in `TownService`, `RestaurantService` and `FoodService` or is it okay like this? When binding what do I need to bind? ``` kernel.Bind<IUnitOfWork>().To<UnitOfWork>(); kernel.Bind<ITownService>().To<TownService>(); kernel.Bind<IRestaurantService>().To<RestaurantService>(); kernel.Bind<IFoodService>().To<TownService>(); ``` Something like this? In short - what I need for adding dependency injection with `Ninject`? I'm really having problems with this and would need help. Thanks a lot in forward.

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