使用Autofac作为服务定位器 [英] Using Autofac as a service locator

问题描述

我使用Autofac处理依赖注入我的应用程序。不过，我有一个组件，做一些反思魔术在运行时，我不知道在编译时哪些依赖它需要。

I'm using Autofac to handle dependency injection in my application. However, I have one component that does some reflection magic at runtime and I don't know at compile-time what dependencies it will need.

通常情况下，我只想有此组件参考容器直接解决为所欲为。然而，就是这个实例化类的类没有引用到容器中。

Ordinarily, I would just have this component reference the Container directly and resolve whatever it wants. However, the class that is instantiating this class has no reference to the Container.

实际上，我的分量对Autofac的依赖。我宁愿更松散的耦合，但是这似乎并没有在这里是一种选择。有没有办法问（构造函数中指定参数时，或使用属性注入，或其他！）Autofac给我在我的构造函数的容器的引用？或者说，有没有有Autofac我提供一个神奇的服务定位器对象，可以解决任何问题一个更清洁的方式？

Effectively, my component has a dependency on Autofac. I'd prefer looser coupling, but that doesn't seem to be an option here. Is there a way to ask (in the constructor args, or using property injection, or whatever!) Autofac to give me a reference to the container in my constructor? Or, is there a cleaner way to have Autofac provide me with a magic service locator object that can resolve anything?

推荐答案

是的，您可以。就拿在 IComponentContext 的依赖关系：

Yes, you can. Just take a dependency on the IComponentContext:

public class MyComponent
{
    public MyComponent(IComponentContext context)
    {
        _context = context;
    }

    public void DoStuff()
    {
        var service = _context.Resolve(...);
    }
}

从注释更新：在 IComponentContext 注入为MyComponent 取决于从哪个为MyComponent 得到解决的范围。什么终身范围注册为MyComponent 来考虑这是重要的。例如。使用 InstancePerLifetimeScope ，上下文将始终解析到在其中根据不同的服务为MyComponent 同一范围内的生活。

Update from the comments: the IComponentContext injected into MyComponent depends on the scope from which MyComponent was resolved. It is thus important to consider with what lifetime scope MyComponent is registered. E.g. using InstancePerLifetimeScope, the context will always resolve to the same scope in which the service depending on MyComponent lives.

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