问在给定复杂继承的情况下保持一致的松散耦合

EN

public interface ICar
{
    ICarDAL DAL;
    bool StartEngine();
    bool StopEngine();
    Driver ChangeDriver(Driver d);
}

public abstract class Car : ICar
{
    private ICarDAL DAL;

    public virtual Car(ICarDAL DALInstance)
    {
        this.DAL = DALInstance;
    }

    public virtual bool StartEngine()
    {
        return this.DAL.UpdateEngine(true);
    }

    public virtual bool StopEngine()
    {
        return this.DAL.UpdateEngine(false);
    }

    public virtual Driver ChangeDriver(Driver d)
    {
        return this.DAL.UpdateDriver(d);
    }
}

public interface ICarDAL<T>
{
    T EFContext;
    bool UpdateEngine(bool b);
    Driver UpdateDriver(Driver d);
}

public abstract class CarDAL<T> : ICarDAL<T>
{
    private T EFContext;

    public virtual bool UpdateEngine(bool b)
    {
        try
        {
            using(T db = new T())
            {
                // Perform DB update
                // return true
            }
        }
        catch(Exception e)
        {
            // Handle and return false
        }
    }

    // and so on..
}

public class FordCarController : Controller
{
    private Car BLLMethods;

    public FordCarController()
    {
        // Init concrete type
        this.BLLMethods = new FordCar();
    }

    public ActionResult DoHeating()
    {
        this.BLLMethods.TurnOnScreenHeating();
        return View();
    }
}