Angular 2 eventEmitter不起作用

Question

I need to make something simple, I want to display a dialog when I click on an help icon.

I have a parent component:

@Component({
  selector: 'app-quotation',
  templateUrl: './quotation.component.html'
})
export class QuotationComponent implements OnInit {

  public quotation: any = {};
  public device: string;
  public isDataAvailable = false;

  @Output() showPopin: EventEmitter<string> = new EventEmitter<string>();

  constructor(private quotationService: QuotationService,
              private httpErrors: HttpErrorsService,
              private popinService: PopinService) {}

  moreInfo(content: string) {
      console.log('here');
    this.showPopin.emit('bla');
  }
}

And his html:

<ul>
    <li *ngFor="let item of quotation.HH_Summary_TariffPageDisplay[0].content">
        <label></label>
        <i class="quotation-popin" (click)="moreInfo()"></i>
        <div class="separator"></div>
    </li>
</ul>

My popin component:

@Component({
  selector: 'app-popin',
  templateUrl: './popin.component.html',
  styleUrls: ['./popin.component.scss']
})
export class PopinComponent implements OnInit {

  public popinTitle: string;
  public popinContent: string;
  public hidden: boolean = true;

  constructor() { }

  openPopin(event):void {
    console.log("here");
    this.hidden = false;
  }

}

His HTML:

<div class="card-block popin-container" (showPopin)="openPopin($event)" *ngIf="!hidden">
  <div class="card">
    <div class="popin-title">
      {{ popinTitle }}
      <i class="icon icon-azf-cancel"></i>
    </div>
    <div class="popin-content">
      {{ popinContent }}
    </div>
  </div>
</div>

My parent component is loaded in a router-outlet and my popin is loaded on the same level than the router-outlet, like this:

<app-nav-bar></app-nav-bar>
<app-breadcrumb></app-breadcrumb>
<div class="container">
  <router-outlet></router-outlet>
</div>

<app-popin></app-popin>

My problem is the eventEmitter doesn't work and i don't know why, someone can explain me ?

thx,

regards

Answer 1

EventEmitters only work for direct Parent-Child component relationships. You do not have this relationship with the components you are describing here.

In a parent-child relatonship, we will see the child's component element within the parent's template. We do not see this in your example.

You have two options:

1. Refactor to use a parent-child relationship
2. Use a service for communication

If you go with option 2, the service should just contain an observable that one component calls next on, and the other component subscribes to.

@Injectable()
export class PopinService {
  showPopin = new ReplaySubject<string>(1); 
}

Inject this in QuotationComponent and modify moreInfo

  moreInfo(content: string): void {
    this.popinService.showPopin.next('bla' + content);
  }

In PopinComponent inject the popinService and add the following:

ngOnInit() {

  this.popinService.showPopin.subscribe(content => {
    this.hidden = false;
    this.popinContent = content;
  });

}

Answer 2

It's because you misuse it.

In your popin component, you just call the function and do a log, and set a variable to false.

And nowhere I can see that you use the app-quotation selector, so you don't really use it, do you ?

Answer 3

Looks like you are sending an output to a child component (popin) . Ideally if you give output that means it should be from child to parent and from parent to child, it is Input.