Windsor MixIn is a Singleton?

Question

I have a MixIn that requires some state to operate.

I am registering it as so..

    container.Register(Component.For(Of ICat) _
                        .         


        

Answer 1

I think I resolved this.

Instead of using Proxy.Mixins, I created a custom Activator()

Public Class MixInActivator(Of T)
   Inherits Castle.MicroKernel.ComponentActivator.DefaultComponentActivator

  Public Sub New(ByVal model As Castle.Core.ComponentModel, ByVal kernel As Castle.MicroKernel.IKernel, ByVal OnCreation As Castle.MicroKernel.ComponentInstanceDelegate, ByVal OnDestruction As Castle.MicroKernel.ComponentInstanceDelegate)
    MyBase.New(model, kernel, OnCreation, OnDestruction)
  End Sub

  Protected Overrides Function InternalCreate(ByVal context As Castle.MicroKernel.CreationContext) As Object

    Dim obj As Object = MyBase.InternalCreate(context)
    If GetType(T).IsAssignableFrom(obj.GetType) = False Then
        Dim options As New Castle.DynamicProxy.ProxyGenerationOptions
        Dim gen As New Castle.DynamicProxy.ProxyGenerator
        options.AddMixinInstance(Kernel.Resolve(Of T))
        obj = gen.CreateInterfaceProxyWithTarget(Model.Service, obj, options)
    End If
    Return obj
 End Function
End Class

So now, the component is registered like this

 container.Register(Component.For(Of ICat) _
                     .ImplementedBy(Of Cat) _
                     .LifeStyle.Is(Castle.Core.LifestyleType.Transient) _
                     .Activator(Of MixInActivator(Of IMixin)))

And IMixin is registered as follows

container.Register(Component.For(Of IMixin) _
                       .ImplementedBy(Of MyMixin) _
                       .LifeStyle.Is(Castle.Core.LifestyleType.Transient) _
                       .Named("MyMixin"))

Answer 2

If you register the mixin with transcient lifestyle, it will create a new instance for each component:

container.Register(
    Component.For<ICat>().ImplementedBy<Cat>()
        .LifestyleTransient()
        .Proxy.MixIns(m => m.Component("mixin")),
    Component.For<MyMixin>().LifestyleTransient().Named("mixin")
);

Answer 3

I'm not sure how it bubbles up to Windsor, but at DynamicProxy level, there's mixin Instance per proxy type. So if you're creating yourself mixin instances, you may be also each time be generating a new proxy type. To circumvent this, override Equals and GetHashCode in your mixed in type.

I may however not be right, so you may want to make sure first.