Question

I’ve written an interface which is implemented by multiple classes. I want to write a Service class which will have all the registered implementations injected into its ctor.

The only solution I can think of is to call the Service Locator within the ctor and ask it to Resolve() all implementations.

Ideally I would like something like this –

interface IVehicle
{
    void Start();
}

class Car : IVehicle
{
    public void Start()
    {
        Console.WriteLine("Car started.");
    }
}

class Truck : IVehicle
{
    public void Start()
    {
        Console.WriteLine("Truck started.");
    }
}

class Motorbike : IVehicle
{
    public void Start()
    {
        Console.WriteLine("Motorbike started.");
    }
}

class VehicleService
{
    // How do I inject all implementations of IVehicle?
    public VehicleService(IEnumerable<IVehicle> vehicles)
    {
        foreach (var vehicle in vehicles)
        {
            vehicle.Start();
        }
    }
}

EDIT – I should mention I’m using Castle Windsor.

Answer 1

You have to use CollectionResolver. Check this Castle Windsor FAQ:

Windsor, by default when you have dependency on IFoo[],
IEnumerable or IList will check if you have a component
registered for that exact type (array or list of IFoo), not if you
have any components registered for IFoo (array of components, is not
the same as a component which is an array). You can change the
behavior to say “When you see array or list of IFoo just give me all
IFoos you can get” you use CollectionResolver.

Direct link to Castle Resolvers: Resolvers.