Angular 2. Can access to the service from everywhere but app.component

Question

It's not my first month with angular so please do not say things like "be sure if you import the service". I can call methods from the service from any component but from app.component.

No errors when importing

import { GeneralService } from './services/generalservice.service';

No errors when declaring

private generalService: GeneralService

Even if i do in @Component({......})

  providers: [GeneralService]

No errors in command line... But for some reason browser says..

Uncaught Error: Can't resolve all parameters for GeneralService: ([object Object], [object Object], [object Object], ?).
at syntaxError (compiler.es5.js:1690)
at CompileMetadataResolver.webpackJsonp.../../../compiler/@angular/compiler.es5.js.CompileMetadataResolver._getDependenciesMetadata (compiler.es5.js:15765)
at .............

I don't even call any function to see an error. It shows right after declaring the service in the constructor.

I just finished second Starbucks's Venti-Americano. But still no light in my brain about this... so please tell me something guys. Thanks.

Answer 1

如果要注入到服务AppComponent ，该服务需要被提供@Component(...)的AppComponent或@NgModule(...)非延迟加载的模块。