在没有构造函数注入的情况下获取服务实例 [英] Getting instance of service without constructor injection

问题描述

我在引导程序中定义了@Injectable服务.我想在不使用构造函数注入的情况下获取服务的实例.我尝试使用ReflectiveInjector.resolveAndCreate，但这似乎创建了一个新实例.

I have a @Injectable service defined in bootstrap. I want to get the instance of the service without using constructor injection. I tried using ReflectiveInjector.resolveAndCreate but that seem to create a new instance.

我要这样做的原因是我有一个由许多组件派生的基本组件.现在，我需要访问服务，但是由于不想将服务注入所有派生组件，所以我不想将其添加到ctor中.

The reason I'm trying to do is I have a base component derived by many components. Now I need to access a service but I don't want to add it to the ctor because I don't want to inject the service on all of the derivative components.

TLDR:我需要一个ServiceLocator.GetInstance<T>()

TLDR: I need a ServiceLocator.GetInstance<T>()

更新:RC5 +的更新代码:存储用于组件的喷油器实例

UPDATE: Updated code for RC5+: Storing injector instance for use in components

推荐答案

是的，ReflectiveInjector.resolveAndCreate()创建一个新的且未连接的注射器实例.

Yes, ReflectiveInjector.resolveAndCreate() creates a new and unconnected injector instance.

您可以注入Angulars Injector实例，并使用它从中获取所需的实例

You can inject Angulars Injector instance and get the desired instance from it using

constructor(private injector:Injector) {
  injector.get(MyService);
}

您还可以将Injector存储在某些全局变量中，然后使用此注入器实例来获取提供的实例，例如，如

You also can store the Injector in some global variable and than use this injector instance to acquire provided instances for example like explained in https://github.com/angular/angular/issues/4112#issuecomment-153811572

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