Question

I just want to know now how to separate code in proper way in MVC3 using EF

As per my project structure.

Presentation -> View & Controller

Domain –> Model (Business Entity)

Data –> RepositoryBase, IRepository, ApplicationDbContext

Services –> 3rd Party Service (PayPal, SMS) or Application Service

ApplicationDbContext require Model as reference.

public sealed class ApplicationDbContext : DbContext
{

    public DbSet<CountryModel> Country { get; set; }

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();
    }
}

1. So is it good to place DbContext in Data ? Or I have to move it into Domain ?

Now in Controller I have to write a code

using (ApplicationDbContext db = new ApplicationDbContext())
{
    var countryRepository = new Repository<Country>(db);

    if (ModelState.IsValid)
    {
        countryRepository.insert(country);
        db.SaveChanges();
    }
}

Is there any way to Separate this code block any Business Layer / Service Layer ?

So we just Call that Layer from controller & just pass the Specific Business Entity in order to perform rest of the operation.

I want to do PL –> BLL –> DLL approach Using MVC 3 & EF ?

Please suggest me the proper way.

Answer 1

So is it good to place DbContext in Data ?

Yes, it’s where it belongs.

Now in Controller I have to write a code

No, you absolutely should not write code like this in the controller because you are now making your controller strongly coupled to the specific data access technology you are using (EF in your case). Even worse you will not be able to unit test your controllers in isolation.

I would recommend you abstracting the operations over the entities in an interface (you already have mentioned it by the way in your question – IRepository). And now your controller could take the repository as dependency:

public class CountriesController: Controller
{
    private readonly IRepository repository;
    public CountriesController(IRepository repository)
    {
        this.repository = repository;
    }

    public ActionResult Index(int id)
    {
        Country country = this.repository.Get<Country>(id);
        return View(country);
    }


    [HttpPost]
    public ActionResult Index(Country country)
    {
        if (ModelState.IsValid)
        {
            this.repository.Insert(country); 
            return RedirectToAction("Success");
        }

        return View(country);
    }
}

Now all you have to do is configure your favorite dependency injection framework to inject the specific implementation of this IRepository into the controller constructor. In your case this specific implementation could be some class that implements the IRepository interface and which is using the ApplicationDbContext inside.

This way you are abstracting away the data access logic from your controllers.