Angular コンポーネントはどのように相互作用するのでしょうか?一般的な対話方法の紹介

export class ChildComponent implements OnInit { @Input() hero: any; @Input('master') masterName: string; // 第二个 @Input 为子组件的属性名 masterName 指定一个别名 master constructor() { } ngOnInit(): void { } }

 
child works!
 
{{hero?.name}} says:
 
I, {{hero?.name}}, am at your service, {{masterName}}.
 

export class ParentComponent implements OnInit { hero = {name: 'qxj'} master = 'Master' constructor() { } ngOnInit(): void { } }

export class ChildComponent implements OnInit { @Input() name: string; @Output() voted = new EventEmitter(); didVote = false; vote(agreed: boolean) { this.voted.emit(agreed); this.didVote = true; } constructor() { } ngOnInit(): void { } }

{{name}}
 Agree Disagree

export class ParentComponent implements OnInit { agreed = 0 disagreed = 0 voters = ['Narco', 'Celeritas', 'Bombasto'] onVoted(agreed: boolean) { agreed ? this.agreed++ : this.disagreed++ } constructor() { } ngOnInit(): void { } }

Should mankind colonize the Universe?
 
Agree: {{agreed}}, Disagree: {{disagreed}}
 

export class ChildComponent implements OnInit, OnDestroy { intervalId = 0 message = '' seconds = 11 clearTimer() { clearInterval(this.intervalId) } ngOnInit() { this.start() } ngOnDestroy() { this.clearTimer() } start() { this.countDown() } stop() { this.clearTimer() this.message = `Holding at T-${this.seconds} seconds` } private countDown() { this.clearTimer() this.intervalId = window.setInterval(() => { this.seconds -= 1 if (this.seconds === 0) { this.message = 'Blast off!' } else { if (this.seconds < 0) { this.seconds = 10 } // reset this.message = `T-${this.seconds} seconds and counting` } }, 1000) } }

{{message}}

export class ParentComponent implements OnInit { constructor() { } ngOnInit(): void { } }

Countdown to Liftoff (via local variable)
 Start Stop 
{{child.seconds}}
 

import {AfterViewInit, Component, ViewChild} from '@angular/core' import {ChildComponent} from '../child/child.component' @Component({ selector: 'app-parent-vc', template: ` 
Countdown to Liftoff (via ViewChild)
 Start Stop 
{{ seconds() }}
  `, }) export class CountdownParentComponent implements AfterViewInit { @ViewChild(ChildComponent) private timerComponent: ChildComponent seconds() { return 0 } ngAfterViewInit() { // Redefine `seconds()` to get from the `ChildComponent.seconds` ... // but wait a tick first to avoid one-time devMode // unidirectional-data-flow-violation error setTimeout(() => { this.seconds = () => this.timerComponent.seconds }, 0) } start() { this.timerComponent.start() } stop() { this.timerComponent.stop() } }