Question

能否等到安吉特米特林匹兹,如同有可能等待亚克斯呼吁(Angular 5 synchronous HTTP打 )一样?

What I want to do is:

A. 儿童部分

@Component({
  template:  <button (click)="emit1()">emit</button> 
})
export class ChildComponent {
  @Output() dataChanged: EventEmitter<number> = new EventEmitter<number>(true);  // synchronous

  emit1(){
    this.dataChanged.emit(1)
  }
}

父母一方积极创建儿童部分

@Component()
export class ParentComponent {
  childComponentRef: ComponentRef<ChildComponent>

  constructor(private resolver: ComponentFactoryResolver, private vcRef: ViewContainerRef) {}

  openChild() {
    const factory = this.resolver.resolveComponentFactory(ChildComponent);
    this.childComponentRef = this.vcRef.createComponent(factory);
    await this.childComponentRef.instance.dataChanged.toPromise()
    alert( emited! )
  }

}

我想(a) 放弃,直到从儿童部分获得价值为止。

Answer 1

您可使用 firstValueFrom。

兑现承诺,将可观测的承诺归于兑现,并兑现承诺,一旦从可观测到的数值中得出第一价值,这一承诺将尽快解决。然后将停止订阅。

It turns everithing that is subscriptable in a promise. Will be something like this:

import { firstValueFrom } from  rxjs ;
@Component()
export class ParentComponent {
  childComponentRef: ComponentRef < ChildComponent > ;

  constructor(
    private resolver: ComponentFactoryResolver,
    private vcRef: ViewContainerRef
  ) {}

  openChild() {
    const factory = this.resolver.resolveComponentFactory(ChildComponent);
    this.childComponentRef = this.vcRef.createComponent(factory);
    await firstValueFrom(this.childComponentRef.instance.dataChanged).then(() => {
      alert( emited! );
    })

  }
}

Answer 2

Angular EventEmitter,是RxJS 编码<>>>>>。他们无所作为,不像问题中提到的那样行事。因此,你们需要接受这一通知。



openChild() {
  const factory = this.resolver.resolveComponentFactory(ChildComponent);
  this.childComponentRef = this.vcRef.createComponent(factory);
  this.childComponentRef.instance.dataChanged.subscribe(
    response => { alert( emited! ) }
  );
}

Answer 3

http://www.learnrxjs.io/learn-rxjs/operators/filtering/first"rel=“nofollow noreferer”>first(),以等待活动者的第一价值:

      openChild() {
        ...
        await this.childComponentRef.instance.dataChanged.pipe(first()).toPromise()
        alert( emited! )
      }

Answer 4

you can emit whenever you want from child component like

this.dataChanged.emit(yourData);

and in your parent component you can try catch that event using

this.childComponentRef.instance.dataChanged.then((res) => {
   console.log(res);
});

友情链接