Question

I’ve a WCF Service which is hosted inside MVC Application. Service interacts with several Repository (I’ve Code First design) to do its job. Currently I create an instance of all Repository classes inside each Service method, I think it is bad and my Service is totally coupled to Repository classes. I want to know how should I implement a nice and clean DI for WCF Service.

Thanks in Advance.

Answer 1

One approach you can take is to inject a repository factory in your service class and then call/get your repository from the factory.

Repository Factory:

public interface IRepositoryFactory
{
    IRepositoryOne GetRepositoryOne();
    IRepositoryTwo GetRepositoryTwo();
}

public class RepositoryFactory: IRepositoryFactory
{
    public DataAccess.RepositoryInterfaces.IRepositoryOne GetRepositoryOne()
    {
        return new RepositoryOne();
    }
    public DataAccess.RepositoryInterfaces.IRepositoryTwo GetRepositoryTwo()
    {
        return new RepositoryTwo();
    }
}

Service Class:

public ServiceClass: IService
{

    private readonly IRepositoryFactory _repositoryFactory;

    public ServiceClass(IRepositoryFactory factory)
    {
        _repositoryFactory = factory;
    }

    public IList<YourItems> GetYourItems()
    {
        var repository = _repositoryFactory.GetRepositoryOne();
        return repository.GetItems(....);
    }
}

With this approach, you’ll need to register and resolve only your repository factory, not all the individual repositories. This is sort of hybrid approach, but I think it’s very clean and easy to understand. Of course, you can always not use a factory and resolve your repositories in every call. I can show a sample of that too, if you’d like.