Autofac and generic command pattern

Question

I am trying to decorate my command handlers and I am trying to resolve them in my processor.

I registered my command like this:

builder.RegisterAssemblyTypes(typeof(ICommandProcessor).Assembly)
    .AsClosedTypesOf(typeof(ICommandHandler<,>))
    .AsSelf().AsImplementedInterfaces().Named("implementor", typeof(ICommandHandler<,>));

builder.RegisterGenericDecorator(
    typeof(CatchValidationErrorsDecorator<,>),
    typeof(ICommandHandler<,>), fromKey: "implementor")
    .AsImplementedInterfaces();

The problem is that when i am not using the Named extension, the generic decorator is not working. When I use the named extension, I am not able to resolve my components like this:

var handerType = typeof (ICommandHandler<,>)
    .MakeGenericType(command.GetType(), typeof (TResult));
dynamic handler = _container.Resolve(handerType);

Someone has an idea how to solve this?

Answer 1

This has given me serious headaches in the past. The registration that eventually did it for me was:

var assembly = typeof(ICommandProcessor).Assembly);

builder.RegisterAssemblyTypes(assembly).As(type =>
    from interfaceType in type.GetInterfaces()
    where interfaceType.IsClosedTypeOf(typeof(ICommandHandler<,>))
    select new KeyedService("implementor", interfaceType));

builder.RegisterGenericDecorator(
    typeof(CatchValidationErrorsDecorator<,>), 
    typeof(ICommandHandler<,>),
    fromKey: "implementor");