Unity Registration by Convention with Interface Interception

Question

I am currently trying to use the registration by convention with interface interception. Unfortunately, it seems that I am doing something wrong because I am running in a StackOverflowException in the Unity.Container.dll on the first resolve...

This is what I tried:

container = new UnityContainer();
container.RegisterTypes(AllClasses.FromAssemblies(Assembly.GetAssembly(typeof(IFoo)), 
  WithMappings.FromMatchingInterface, 
  getInjectionMembers: c => new InjectionMember[] { new Interceptor<InterfaceInterceptor>(), new InterceptionBehavior<IBarBehavior>()});

It seems that now all classes are registered, instead of only classes with matching interfaces (Foo --> IFoo). Without the interface interception, the statement is fine and my classes are registered as expected.

Any idea or help would be great!

Update:

I have found this post in a different question that states when a LifeTimeManager or interception behavior is used all types are registered. By using these information, the following code produced the expected outcome:

container.RegisterTypes(AllClasses.FromAssemblies(Assembly.GetAssembly(typeof(IFoo)).
  Where(t => t.GetTypeInfo().GetInterface("I" + t.Name) != null), 
  WithMappings.FromMatchingInterface,
  getInjectionMembers: c => new InjectionMember[] { new Interceptor<InterfaceInterceptor>(), new InterceptionBehavior<IBarBehavior>()});

score 0 · Answer 1 · answered Nov 27 '17 at 18:51

If I remember correctly, you are running into a StackOverflowException because of a cyclic dependency issue in your injections. This occurs when you are injecting a number of dependencies, say you have,

public YourController(IA a, IB b, IC c){  ... }
public ConcreteA(IB b, IC c) { ... }
public ConcreteB(IA a) { ... }

The issue, with a set up like this is that, ConcreteA needs ConcreteB (IB) so it injects it. While injecting ConcreteB, Unity finds that ConcreteA (IA) is needed so it injects it also, and this will continue in a loop until that stack is overflowed.

If you start tracing from your default entry point, you find that one or more of your injections are dependent on one another causing a cyclic loading of dependencies like above.

Once you eliminate this cyclic dependency, you will be fine.

I guess the direction is right, but there is no cyclic dependency without the interface interception. So I think there might be something wrong... — royalTS, Nov 30 '17 at 06:31

Unity Registration by Convention with Interface Interception

1 Answers1