Autofac的委托工厂，以及容器的传递 [英] Autofac delegate factories, and passing around container

问题描述

我对委托工厂有疑问: autofac文档

I have a question about delegate factories: autofac docs

我了解他们是如何建立工厂的，但是我没有解决问题的部分:

I understand how they set up the factories but I do not get the resolving part:

var shareholdingFactory = container.Resolve<Shareholding.Factory>();
var shareholding = shareholdingFactory.Invoke("ABC", 1234);

看来您必须绕过容器才能解决.也许我必须使用仅在运行时才知道的参数来调用某些东西.如何在不将容器传递给例如服务方法的情况下做到这一点?

It looks like you have to pass around the container in order to resolve. Maybe I have to Invoke something with parameters I only know at runtime. How do I do that without passing the container to for example a service method?

更新

那么您应该通过工厂?

So you are supposed to pass the factories instead?

推荐答案

Autofac可以自动解析工厂，即没有容器:

Autofac can automatically resolve factories, i.e. without the container:

public class ShareHolding
{
    public ShareHolding(int accountId)
    {
        // do whatever you want
    }
}

public class MyApp
{
    private readonly ShareHolding _shareHolding;
    public MyApp(Func<int, ShareHolding> shareHoldingFactory)
    {
        _shareHolding = shareHoldingFactory(99);
    }

    public void Run()
    {
        // do whatever you want with the _shareHolding object
    }
}

Autofac注册

var containerBuilder = new ContainerBuilder();
containerBuilder.RegisterType<ShareHolding>(); // not a singleton
containerBuilder.RegisterType<MyApp>().SingeInstance();

var myApp = containerBuilder.Resolve<MyApp>();
myApp.Run();

现在，如果您的ShareHolding类型的ctor像这样:

Now, if your ShareHolding type had ctor like:

public class ShareHolding
{
    public delegate ShareHolding Factory(int accountId, int userId);
    public ShareHolding(int accountId, int userId)
    {
        // do whatever you want
    }
}

然后，您将需要一个委托工厂，因为Autofac使用类型信息来解析构造函数，而使用参数名称来委托工厂.您的用法将变为:

Then you would need a delegate factory because Autofac resolves constructors using type information and delegate factories using parameters names. Your usage would then become:

public class MyApp
{
    public MyApp(ShareHolding.Factory shareHoldingFactory)
    {
        ....
    }
}

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