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?

Answer 1

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