Autofac 注册 IEnumerable 和个人来解决它们

Question

我们都知道您可以注册多个实例并使用 Autofac 解决它们

builder.RegisterType<Foo1>().As<IFoo>();    
builder.RegisterInstance(new Foo2("something")).As<IFoo>();    
builder.RegisterInstance(new Foo2("another")).As<IFoo>();

//and finally
var foos = ctx.Resolve<IEnumerable<IFoo>>();

现在我必须注册一些 foos 如下：

builder.Register(ctx =>{
   var factory = ctx.Resolve<IFooFactory>();
   var allTheFoos = config.FooConfigs.Select(fooConfig => factory.CreateFoo(fooConfig));
   return allTheFoos;
}).As<IEnumerable<IFoo>>();

这仍然有效，但我认为这不是正确的方法。除此之外，我还想补充一个IFoo

的额外注册

builder.RegisterInstance(new Foo2("this one")).As<IFoo>();

如果我现在解析 IEnumerable，我会将集合显式注册为 IEnumerable，但我需要它还包含 Foo2("this one");

//contains allTheFoos, but not Foo2("this one");
var foos = ctx.Resolve<IEnumerable<IFoo>>();

注册本身无法合并，因为它们出于某种原因位于不同的模块中。我想我需要单独注册工厂创建的 foos，但这需要在 Register 方法（或等效方法）中，因为我需要能够首先解析工厂本身。我希望是这样的：

builder.Register(ctx => /* generate foos*/).AsMultiple<IFoo>();

编辑：基于答案

public class BotRegistrationSource : IRegistrationSource
{
    private readonly IConfiguration _config;

    public BotRegistrationSource(IConfiguration config)
    {
        _config = config;
    }

    public IEnumerable<IComponentRegistration> RegistrationsFor(Service service,
        Func<Service, IEnumerable<ServiceRegistration>> registrationAccessor)
    {
        var swt = service as IServiceWithType;
        if (!(swt?.ServiceType.IsAssignableTo<IBot>() ?? false))
        {
            return Enumerable.Empty<IComponentRegistration>();
        }

        return  _config.GetSection("Bots")
            .GetChildren()
            .Select(c =>
                new ComponentRegistration(
                    Guid.NewGuid(),
                    new DelegateActivator(swt.ServiceType, (componentContext, _) =>
                    {
                        var botFactory = componentContext.Resolve<IBotFactory>();
                        var config = botFactory.CreateConfig();
                        c.Bind(config);
                        var bot = botFactory.Create(config);
                        bot.Enable();
                        return bot;
                    }),
                    new CurrentScopeLifetime(),
                    InstanceSharing.None,
                    InstanceOwnership.OwnedByLifetimeScope,
                    new[] { service },
                    new Dictionary<string, object>()));
    }

    public bool IsAdapterForIndividualComponents => false;
}

Answer 1

我想你要看的是a registration source. Registration sources are a way to do exactly what you want - provide one or more components to the container when a service is requested. The documentation has an example。

Autofac 注册 IEnumerable 和个人来解决它们

Autofac register IEnumerable and individuals to resolve them all

c#

autofac