Question

I’m using MVC3 and currently i’m following a practice such that I declare one instance of DB Container for every controller. I use that container instance for every request coming to that controller. If I need to go to my models for a query or sth, I send that instance as a parameter to the model’s function. So for the whole application, I create and use 4-5 different instances of DB Container class. My question is, does this have a good or bad effect on my database operations? Does it matter to create a seperate container instance? What is the proper way to use container classes?

I believe the mentioned class was called DBContext before.

Answer 1

I am not sure it is what you mean but I can give you an example of an approach I’m following rather often:

Create a sort of ‘domainservice class’ for the DBContext

public class MyDomainService : IDisposable
{
    private MyDbEntities dbo;
    private bool isDisposed;

    public MyDomainService()
    {
        dbo = new MyDbEntities();
    }

    public User GetUser(string userName)
    {
        return (from usr in dbo.Users
                where usr.UserName == userName
                select usr).SingleOrDefault();
    }

    public void Dispose()
    {
        if (isDisposed)
            return;
        isDisposed = true;
        dbo.Dispose();
    }
}

Create a custom Controller class that extends Controller or AsyncController
and override the Initialize and Dispose methods:

public class MyController : Controller
{

    protected MyDomainService DomainService { get; private set; }

    protected override void Initialize(System.Web.Routing.RequestContext
                                       requestContext)
    {
        base.Initialize(requestContext);
        DomainService = new MyDomainService();
    }

    protected override void Dispose(bool disposing)
    {
        DomainService.Dispose();
        base.Dispose(disposing);
    }

}

Now you can use the following approach in per example the HomeController inheriting MyController

public class HomeController : MyController
{

    public ActionResult Index()
    {
        return View();
    }

    [HttpPost]
    public ActionResult Index(string username)
    {
        var user = DomainService.GetUser(username);
        if (user != null)
            return RedirectToAction("Account", "Information");
        return View();
    }

}

This will keep your controllers rather clean.