如何将事件从父母传给孩子? [英] How to emit an event from parent to child?

问题描述

我当前正在使用Angular2.通常，我们先使用@Output() addTab = new EventEmitter<any>();然后使用addTab.emit()向父组件发出事件.

I am currently using Angular 2. Usually we use @Output() addTab = new EventEmitter<any>(); and then addTab.emit() to emit an event to parent component.

从父母到孩子，我们有什么方法可以做反之吗?

Is there any way we can do it vice cersa, from parent to child?

推荐答案

使用 RxJs ，您可以在父组件中声明Subject并将其作为Observable传递给子组件child组件只需要订阅此Observable.

Using RxJs, you can declare a Subject in your parent component and pass it as Observable to child component, child component just need to subscribe to this Observable.

父组件

eventsSubject: Subject<void> = new Subject<void>();

emitEventToChild() {
  this.eventsSubject.next();
}

父母HTML

<child [events]="eventsSubject.asObservable()"> </child>    

子组件

private eventsSubscription: Subscription;

@Input() events: Observable<void>;

ngOnInit(){
  this.eventsSubscription = this.events.subscribe(() => doSomething());
}

ngOnDestroy() {
  this.eventsSubscription.unsubscribe();
}

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