Castle Windsor: How do I inject all implementations of interface into a ctor?

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.

Answer 2

I know this has already been answered, but I thought an example of how to add the CollectionResolver would be useful, so here it is.

Call AddSubResolver before registering the components in the container, e.g.

container = new WindsorContainer();
container.Kernel.Resolver.AddSubResolver(new CollectionResolver(container.Kernel));

Register the components as normal:

container.Register(
    Component.For<IVehicle>().ImplementedBy<Car>(),
    Component.For<IVehicle>().ImplementedBy<Truck>(),
    Component.For<IVehicle>().ImplementedBy<Motorbike>()
);

Answer 3

Found this answer useful though I was still missing how to register all the implementations of a given interface.

Hope this helps!

container.Register(
            Classes.FromAssemblyContaining<IVehicle>()
                .BasedOn<IVehicle>().WithService.FromInterface()
            );

Answer 4

The answers here are all correct but I just wanted to add a little extra wrinkle to it: You have to add the sub-resolver BEFORE you register your components.

This will work:

container = new WindsorContainer();
container.Kernel.Resolver.AddSubResolver(new CollectionResolver(container.Kernel));
container.Register(
    Component.For<IVehicle>().ImplementedBy<Car>(),
    Component.For<IVehicle>().ImplementedBy<Truck>(),
    Component.For<IVehicle>().ImplementedBy<Motorbike>()
);

This will NOT work

container = new WindsorContainer();
container.Register(
    Component.For<IVehicle>().ImplementedBy<Car>(),
    Component.For<IVehicle>().ImplementedBy<Truck>(),
    Component.For<IVehicle>().ImplementedBy<Motorbike>()
);
container.Kernel.Resolver.AddSubResolver(new CollectionResolver(container.Kernel));