Autofac: Batch registration of open generic types

问题:

I got an assembly with many concrete types that implement IHandler<TCommand>, such as the following:

public class MoveCustomerHandler : IHandler<MoveCustomerCommand>
{
    void IHandler<MoveCustomerCommand>.Handle(MoveCustomerCommand c)
    {
        // some business logic for moving a customer.
    }
}

Currently, I'm registering them one by one as follows:

builder.RegisterType<MoveCustomerHandler>()
    .As<IHandler<MoveCustomerCommand>>();

builder.RegisterType<ProcessOrderHandler>()
    .As<IHandler<ProcessOrderCommand>>();

builder.RegisterType<SomeOtherFancyHandler>()
    .As<IHandler<SomeOtherFancyCommand>>();

// Many handler registrations here...

The command handlers are injected using constructor injection, as can be seen below:

public class OrderController
{
    private readonly IHandler<ProcessOrderCommand> handler;

    public OrderController(IHandler<ProcessOrderCommand> handler)
    {
        this.handler = handler;
    }
}

Is there a way to batch register all my handlers in an easy way using Autofac?

回答1:

In a similar style to Jim's answer but taking advantage of AsClosedTypesOf:

Assembly[] assemblies = GetYourAssemblies();

builder.RegisterAssemblyTypes(assemblies)
    .AsClosedTypesOf(typeof(IHandler<>));

回答2:

You probably want something like this, although I'm not sure how IsAssignable() behaves with open generics.

Assembly[] assemblies = GetYourAssemblies();

builder.RegisterAssemblyTypes(assemblies)
    .Where(t => t.IsAssignableFrom(typeof(IHandler<>)))
    .AsSelf()
    .AsImplementedInterfaces();