Dependency Injection with repository "Generator"

Question

I did my research and I can’t find any specific example of what I want to do.

I successfully implement Ninject into me MVC project. Everything works perfect. However, I want to do a last step.

Until now, I have been working like this (normal DI pattern):

public class myController : Controller
{  
    private iMyInterface myRepository;

    public myController(iMyInterface myRepository)
    {
        this.myRepository = myRepository;
    }        

    public ActionResult list(){
        return view(myRepository.getMyList())
    }        

    // rest o the code ...
}

My Question is; there is a way to do something like this? (Repository “Generator”)

public class myController : Controller
{  
    private iMyInterface myRepository = specialClass.GetMyRepository();

    public ActionResult list(){
        return view(myRepository.getMyList()) }

    // rest o the code ...    
}

I aware I’m writing a nonsense code, but the idea is to be able to do something similar.

Any recommendation?

What's the intension behind this? Your current solution seems to be ok. So why changing to a service locator like design? — Remo Gloor, Mar 13 '11 at 14:27

Mark Seemann · Accepted Answer · 2011-03-13T21:47:43.917

I don't know what specialClass is supposed to be, but this looks a lot like the Service Locator anti-pattern in action.

The first option where the repository is injected through the constructor is better, because it gives you more options, including using specialClass:

var controller = new myController(specialClass.GetMyRepository());

I don't know Ninject, but most DI Containers give you an option to map an interface to a method call that returns an instance of the interface.

score 0 · Answer 2 · answered Mar 13 '11 at 14:30

0

I would rather take a repository "Generator" in a constructor. That would give you the same result, but with a correct injection.

answered Mar 13 '11 at 14:30

Tengiz

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2

No, that would be a Leaky Abstraction. See e.g. http://stackoverflow.com/questions/4648318/dependency-injection-new-instance-required-in-several-of-a-classes-methods/4650050#4650050 for an similar question and an explanation for why it would be a leaky abstraction. – Mark Seemann Mar 13 '11 at 14:44
Personally I prefer classic dependency injection approach http://martinfowler.com/articles/injection.html – Tengiz Mar 15 '11 at 16:09

Dependency Injection with repository "Generator"

2 Answers2