CODEWITHSUNDEEP
c#.netdependency-injectionstructuremap
Cortlendt
Cortlendt

Reputation: 2240

Structure map - understanding Use and Add semantics

I have the following code with NServiceBus & StructureMap 2.6.2 wired up together:

var bus = Configure.WithWeb().StructureMapBuilder(container)
ObjectFactory.Container.Configure(r => 
    r.For<IBus>().Singleton().Use(Configure.Instance.CreateBus().Start())
);

container.Configure(r => r.For<IBus>().Singleton().Add<MyBus>().Named("named"));

I want first registration to be a default one, second registration to be available as a named one. But when I run:

var bus1 = container.GetInstance<IBus>();
var bus2 = container.GetInstance<IBus>("named");

I get both instances of type MyBus. According to this question first instance must come from first registration (of type UnicastBus) but it is not.

Am I understanding Use and Add semantics wrong?

Upvotes: 1

Views: 720

Answers (2)

LetMeCodeThis
LetMeCodeThis

Reputation: 591

Both registrations:

ObjectFactory.Container.Configure(r => 
    r.For<IBus>().Singleton().Use(Configure.Instance.CreateBus().Start())
);

and

container.Configure(r => r.For<IBus>().Singleton().Add<MyBus>().Named("named"));

are applied do different instances of container (container != ObjectFactory.Container). This results in container having only one registration of IBus (MyBus) and that is why you can only resolve this dependency. When you register only one type (even if it is named instance) for specific plugin type you are able to resolve it when using container.GetInstance<TPluginType>(). To fix this issue and have expected behavior you need to change this registration:

ObjectFactory.Container.Configure(r => 
    r.For<IBus>().Singleton().Use(Configure.Instance.CreateBus().Start())
);

with this:

container.Configure(r => 
    r.For<IBus>().Singleton().Use(Configure.Instance.CreateBus().Start())
);

Tested this issue in both versions of SM (2.6 and 3+) and the behavior is the same on these versions.

Hope this helps!

Upvotes: 1

NightOwl888
NightOwl888

Reputation: 56869

You are registering the first instance in the ObjectFactory container instance. The second instance is being registered in a local container instance named container.

For this behavior to work right, you need to use the same container instance for both registrations.

On a side note, you should never use the ObjectFactory static instance (as per the documentation).

The static ObjectFactory wrapper for Container is still available in 3.0, but we strongly recommend against using it for new applications. It only exists for easier compatibility with older installations.

Upvotes: 1

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