Getting instance of service without constructor injection

angular angular2-di angular2-injection
dstr picture dstr · May 27, 2016 · Viewed 87.7k times · Source

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.

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

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

Answer

G&#252;nter Z&#246;chbauer picture Günter Zöchbauer · May 27, 2016

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

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

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

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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