详解Angular2组件之间如何通信

组件之间的共享可以有好几种方式

父->子 input 方式

import {Component,Input} from 'angular2/core'; @Component({ selector: 'child', template: ` <h2>child {{content}}</h2> ` }) class Child { @Input() content:string; } @Component({ selector: 'App', directives: [Child], template: ` <h1>App</h1> <child [content]="i"></child> ` }) export class App { i:number = 0; constructor() { setInterval(()=> { this.i++; }, 1000) } }

子->父 output 方式

import {Output,EventEmitter,Component} from 'angular2/core'; @Component({ selector: 'child', template: ` <h2>child</h2> ` }) class Child { @Output() updateNumberI:EventEmitter<number> = new EventEmitter(); i:number = 0; constructor() { setInterval(()=> { this.updateNumberI.emit(++this.i); }, 1000) } } @Component({ selector: 'App', directives: [Child], template: ` <h1>App {{i}}</h1> <child (updateNumberI)="numberIChange($event)"></child> ` }) export class App { i:number = 0; numberIChange(i:number){ this.i = i; } }

子获得父实例

如果不了解forwardRef用处的的可以看 #11

@Host 表示这个Injector必须是host element在这里可以理解为 parent

import {Host,Component,forwardRef} from 'angular2/core'; @Component({ selector: 'child', template: ` <h2>child</h2> ` }) class Child { constructor(@Host() @Inject(forwardRef(()=> App)) app:App) { setInterval(()=> { app.i++; }, 1000); } } @Component({ selector: 'App', directives: [Child], template: ` <h1>App {{i}}</h1> <child></child> ` }) export class App { i:number = 0; }

父获得子实例

子元素指令在父constructor时是获取不到的，所以必须在组件的ngAfterViewInit生命周期钩子后才能获取，如果对组件生命周期不了解的话，可以参考#56

import {ViewChild,Component} from 'angular2/core'; @Component({ selector: 'child', template: ` <h2>child {{i}}</h2> ` }) class Child { i:number = 0; } @Component({ selector: 'App', directives: [Child], template: ` <h1>App {{i}}</h1> <child></child> ` }) export class App { @ViewChild(Child) child:Child; ngAfterViewInit() { setInterval(()=> { this.child.i++; }, 1000) } }

service 方式

import {Component,Injectable} from 'angular2/core'; @Injectable(); class KittencupService { i:number = 0; } @Component({ selector: 'child', template: ` <h2>child {{service.i}}</h2> ` }) class Child { constructor(public service:KittencupService){ } } @Component({ selector: 'App', directives: [Child], providers: [KittencupService], template: ` <h1>App {{i}}</h1> <child></child> ` }) export class App { constructor(service:KittencupService) { setInterval(()=> { service.i++; }, 1000) } }

service EventEmitter方式

import {Component,Injectable,EventEmitter} from 'angular2/core'; @Injectable() class KittencupService { change: EventEmitter<number>; constructor(){ this.change = new EventEmitter(); } } @Component({ selector: 'child', template: ` <h2>child {{i}}</h2> ` }) class Child { public i:number = 0; constructor(public service:KittencupService){ service.change.subscribe((value:number)=>{ this.i = value; }) } } @Component({ selector: 'App', directives: [Child], providers: [KittencupService], template: ` <h1>App {{i}}</h1> <child></child> ` }) export class App { i:number = 0; constructor(service:KittencupService) { setInterval(()=> { service.change.emit(++this.i); }, 1000) } }