Question

Following scenario:

We use the Fluent API to register all components in an assembly and two components tyepof(A) with named keys. Another class B with two properties typeof(A) should get the named components injected.

Sample:

public class A : IA {}

public class B : IB
{
    [Named("first")]
    public IA First { get; set; }

    [Named("second")]
    public IA Second { get; set; }
}

// ...

container.Register(Component.For<IA>().Instance(new A(value1)).Named("first"));
container.Register(Component.For<IA>().Instance(new A(value2)).Named("second"));

// ...
var b = container.Resolve<IB>(); // named instances of A get injected to B using the Named attribute

Is this possible with an attribute like Named or only with the Xml Config?

Answer 1

The standard way to do this in Windsor is using service overrides. In your example, when you register B you’d do it like this:

container.Register(Component.For<IB>().ImplementedBy<B>()
                     .ServiceOverrides(new {First = "first", Second = "second"}));

(there are other ways to express this, check the linked docs)

Using a Named attribute as you propose pollutes the code with unrelated concerns (B should not care about what As get injected)