Is it bad practice to have a repository that manually opens and closes a db connection?

Question

Environment: ASP.NET MVC3 C#

Say I have some repository (semi-psuedo):

public interface IRepository
{
 create();read();update();delete();opendb();closedb();
}

public class CarRepository : IRepository
{
 private DbContext namedDbContext;

 public void opendb()
 {
  namedDbContext = new DbContext();
 }
 public void closedb()
 {
  namedDbContext.dispose();
 }
}

And then in a controller the repository is injected and used as follows to manually control the db connection lifetime:

public class SomeController : Controller
{
    private IRepository CarRepository;

    public void SomeController(IRepository _carRepository)
    {
        CarRepository = _carRepository;
    }

    public ActionResult SomeAction(int CarId)
    {
        CarRepository.opendb();
        var car = CarRepository.read(CarId);
        CarRepository.closedb();
    }
}

Is this considered bad practice because it is taking the control of the connection from the repository and placing it in the controller? I am worried about memory leaks from using dependency injection and want to ensure duplicate connections are not opened, nor long running and unused.

Answer 1

Yes. Sure. Most ADO.NET drivers uses connection pooling, so the actual connection process isn't that heavy. And you have TransactionScope which can take care of transaction over multiple connections, but it wont be as fast as one transaction over one connection.

I am worried about memory leaks from using dependency injection and want to ensure duplicate connections are not opened, nor long running and unused.

A IoC will guaranteed clean up the connection (a large user base have made sure of that). There is no guarantee that a programmer will do the cleanup in all places.