注入实现某个接口的所有服务 [英] Inject all Services that implement some Interface

问题描述

简单场景:

我有多个实现通用接口的服务.所有这些服务都在 bootstrap 方法中注册.

I have multiple Services that implement a common Interface. All those Services are registered within the bootstrap method.

现在我想要另一个服务，它注入所有实现公共接口的注册服务.

Now I'd like to have another Service, which injects all registered Services that implement the common Interface.

即

export interface MyInterface {
    foo(): void;
}

export class Service1 implements MyInterface {
    foo() { console.out("bar"); }
}

export class Service2 implements MyInterface {
    foo() { console.out("baz"); }
}

export class CollectorService {
    constructor(services:MyInterface[]) {
        services.forEach(s => s.foo());
    }
}

这有可能吗?

推荐答案

您需要像这样注册您的服务提供商:

You need to register your service providers like this:

boostrap(AppComponent, [
  provide(MyInterface, { useClass: Service1, multi:true });
  provide(MyInterface, { useClass: Service2, multi:true });
]);

这仅适用于没有接口的类，因为接口在运行时不存在.

This will work only with classes not with interfaces since interfaces don't exist at runtime.

要使其与接口一起工作，您需要对其进行调整:

To make it work with interfaces, you need to adapt it:

bootstrap(AppComponent, [
  provide('MyInterface', { useClass: Service1, multi:true }),
  provide('MyInterface', { useClass: Service2, multi:true }),
  CollectorService
]);

并以这种方式注入:

@Injectable()
export class CollectorService {
  constructor(@Inject('MyInterface') services:MyInterface[]) {
    services.forEach(s => s.foo());
  }
}

有关更多详细信息，请参阅此 plunkr:https://plnkr.co/edit/HSqOEN?p=预览.

See this plunkr for more details: https://plnkr.co/edit/HSqOEN?p=preview.

查看此链接了解更多详情:

See this link for more details:

• http://blog.thinkram.io/angular2/2015/11/23/multi-providers-in-angular-2.html

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