使用Simple Injector注册相同类型的实例

Question

I have just picked up Simple Injector and all I currently want to do is this:

Container.Register<IMessageHandler>(() => new MessageHandlerOne());
Container.Register<IMessageHandler>(() => new MessageHandlerTwo());

I'm just trying to register two message handlers, so I can later iterate through them.

To get back these registered instances, this method sounds like it would do the trick.

var instances = Container.GetAllInstances<IMessageHandler>();
//why doesn't instances contain both MessageHandlerOne, and MessageHandlerTwo ?

Instead this returns back an empty IEnumerable .

What am I doing wrong? For something named Simple Injector you would think this would work? Am I thinking about this the wrong way?

Answer 1

What you are trying to do should fail with an exception on the second call to Container.Register<IMessageHandler> since the Simple Injector API clearly differentiates the registration of collections .

In other words, if you want to resolve a collection, you should register a collection:

Container.Collection.Register<IMessageHandler>(
    typeof(MessageHandlerOne), 
    typeof(MessageHandlerTwo));