Cast of the intercepted(Castle Windsor interceptor) interface to another interface

Question

Example classes

public interface IDog
{
    string Bark();
}

public interface ICat
{
    string Meow();
}

public class DogCat : IDog, ICat
{
    public string Bark()
    {
        return "Bark";
    }

    public string Meow()
    {
        return "Meow";
    }
}

In the world without interceptors if I have instance I can cast it easily.

IDog dog = new DogCat();
ICat cat = (Cat)dog;

Here's the test. If I don't use LoggingInterceptor, I would get reference to a DogCat and cast will work. But as I use interface it can't cast. The test passes, i.e. throws InvalidCastException. How can I make it do not throw and cast it? Can I get a proxy which can be used as ICat?

[TestFixture]
public class LoggingInterceptorTests2
{
    private WindsorContainer _container;
    private Mock<ILogger> _mock;

    [SetUp]
    public void SetUp()
    {
        _container = new WindsorContainer();
        _mock = new Mock<ILogger>(MockBehavior.Loose);
        _container.Register(
            Component.For<LoggingInterceptor>().LifestyleTransient().DependsOn(new { HeavyLogging = true }),
            Component.For<IDog>().ImplementedBy<DogCat>().Named("dog").Interceptors<LoggingInterceptor>(),
            Component.For<ICat>().ImplementedBy<DogCat>().Named("cat").Interceptors<LoggingInterceptor>()
            );
    }

    [Test]
    public void CastInterceptorForATypeImplementing2Interfaces()
    {
        var dog = _container.Resolve<IDog>();
        dog.Bark().Should().Be("Bark");

        Action cat = () =>
        {
            var t = (ICat)dog;//I want it to be casted here
        };
        cat.ShouldThrow<InvalidCastException>();
    }
}

The task is I have a banch of services performing tasks and in some cases in may be extended services. I was going to cast to extended and if the cast is successful I do extended operations. All is fine but I need to use it as Wcf & use interceptors. How can I do that?

Why in dogs name do you want to cast that? The fact that you need to cast seems flawed to me. Why don't you just inject both an `IDog` and an `ICat`? — Steven, Feb 02 '14 at 14:16
I can't inject IDog & ICat. In fact I'm injecting IEnumerable using collection resolver. If I Inject IEnumerable which is let's say half of the size IEnumerable. I can't figure out for IDog an optional ICat. — user1325696, Feb 02 '14 at 21:00
Use mixins. The chosen answer here (http://stackoverflow.com/questions/678131/windsor-mixin-is-a-singleton) gives an example, though it's in VB rather than C#. — Phil Degenhardt, Feb 03 '14 at 06:41

score 1 · Accepted Answer · answered Feb 04 '14 at 09:29

try changing to :

Component.For<IDog,DogCat>().ImplementedBy<DogCat>().Named("dog").Interceptors<LoggingInterceptor>(),
Component.For<ICat,DogCat>().ImplementedBy<DogCat>().Named("cat").Interceptors<LoggingInterceptor>()

This should force windsor to use a class proxy. I do agree however with the comment above that your design seems to be flawed. It's been a while since I've used this, so let me know if it doesn't work, then I'll look it up.

Kind Regards, Marwijn

I've changed the design, but still many thanks. It works. It was exactly I was looking for. — user1325696, Feb 04 '14 at 13:36

Cast of the intercepted(Castle Windsor interceptor) interface to another interface

1 Answers1