Autofac, how to intercept the service with an instance of a Aspect but not with the Type of Aspect?

Question

I have an Autofac as an IoC container. I want to register Aspect for the some types. I can do it like this:

build.RegisterType(myType).As(ImyType).EnableInterfaceInterceptors().InterceptedBy(typeof(Aspect));

But what if I need to register the interceptor to the some amount of classes using not a Type of interceptor but it's instance. Lets look how I think it should look like:

Aspect aspectInstance = new Aspect("some data to constructor")
build.RegisterType(myType).As(ImyType).EnableInterfaceInterceptors().InterceptedBy(aspectInstance);

I was doing so using Ninject IoC. but what about Autofac? Thx for any advance!

Answer 1

Check out the Autofac wiki page on Autofac.Extras.DynamicProxy2. It shows an example of a CallLogger interceptor where it registers a lambda as the interceptor:

var builder = new ContainerBuilder(); 
builder.RegisterType<SomeType>()
       .As<ISomeInterface>()
       .EnableInterfaceInterceptors(); 
builder.Register(c => new CallLogger(Console.Out));
var container = builder.Build();
var willBeIntercepted = container.Resolve<ISomeInterface>();

For your case, just switch it to register an instance.

var builder = new ContainerBuilder(); 
builder.RegisterType<SomeType>()
       .As<ISomeInterface>()
       .EnableInterfaceInterceptors()
       .InterceptedBy(typeof(Aspect));
var interceptor = new Aspect();
builder.RegisterInstance(interceptor);
var container = builder.Build();
var willBeIntercepted = container.Resolve<ISomeInterface>();

Alternatively, you can use named interceptors if you don't want your aspect to be typed.

var builder = new ContainerBuilder(); 
builder.RegisterType<SomeType>()
       .As<ISomeInterface>()
       .EnableInterfaceInterceptors()
       .InterceptedBy("my-aspect-instance");
var interceptor = new Aspect();
builder.RegisterInstance(interceptor)
       .Named<IInterceptor>("my-aspect-instance");
var container = builder.Build();
var willBeIntercepted = container.Resolve<ISomeInterface>();

Again, check out the wiki - there are lots of ways to associate the interceptor with the class being intercepted, including named, typed, attributes... lots of samples on the wiki.