MVC: Controller knows about persistence?

Question

Just getting started with MVC, long-time WebForms experience.

I don't want to decorate my entities with UI-oriented properties like "display name" or "required", plus a lot of them have more methods and properties than I care to expose on a view.

So I'm experimenting with ViewModels that wrap, or in other ways interact with the actual entities in my system. What I don't like is how the Controller has to know to query a repository and then instantiate a ViewModel to wrap the entity it got back.

What are best-practices for a controller to interact with ViewModels without having to know how they're persisted? All the examples I see talk directly to EntityFramework or other ORM's.

I was thinking about static methods on the ViewModel classes that take an IRepository reference and an ID to load and return the ViewModel. Does that make sense?

Answer 1

Use DependencyInjection to pass your Repository to your controller.

public HomeController
{
    private readonly IHomeRepository repo;

    public HomeController(IHomeRepository repository)
    {
        repo = repository;
    }
}

Then inside your action methods, get the items, and create your ViewModels from those objects.

public ActionResult Index()
{
    // IEnumerable models are bad, but this is just a quick demo.
    var viewModels = repo.GetWidgets().Select(w => new WidgetModel(w));

    return View("Index", viewModels);
}