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

rush:js;"> import {Component,Input} from 'angular2/core'; @Component({ selector: 'child',template: `

child {{content}}

` }) class Child { @input() content:string; }

@Component({
selector: 'App',directives: [Child],template: `

App

` }) export class App {

i:number = 0;

constructor() {
setInterval(()=> {
this.i++;
},1000)
}

}

子->父 output 方式

rush:js;"> import {Output,EventEmitter,Component} from 'angular2/core';

@Component({
selector: 'child',template: `

child

` }) class Child { @Output() updateNumberI:EventEmitter = new EventEmitter(); i:number = 0;

constructor() {
setInterval(()=> {
this.updateNumberI.emit(++this.i);
},1000)
}
}

@Component({
selector: 'App',template: `

App {{i}}

` }) 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

rush:js;"> import {Host,Component,forwardRef} from 'angular2/core';

@Component({
selector: 'child',template: `

child

` }) class Child {

constructor(@Host() @Inject(forwardRef(()=> App)) app:App) {
setInterval(()=> {
app.i++;
},1000);
}
}

@Component({
selector: 'App',template: `

App {{i}}

` }) 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

rush:js;"> import {ViewChild,template: `

child {{i}}

` }) class Child { i:number = 0; }

@Component({
selector: 'App',template: `

App {{i}}

` }) export class App {

@ViewChild(Child) child:Child;
ngAfterViewInit() {
setInterval(()=> {
this.child.i++;
},1000)
}

}

service 方式

rush:js;"> import {Component,Injectable} from 'angular2/core';

@Injectable();
class KittencupService {
i:number = 0;
}

@Component({
selector: 'child',template: `

child {{service.i}}

` }) class Child {

constructor(public service:KittencupService){

}
}

@Component({
selector: 'App',providers: [KittencupService],template: `

App {{i}}

` }) export class App {

constructor(service:KittencupService) {
setInterval(()=> {
service.i++;
},1000)
}

}

service EventEmitter方式

rush:js;"> import {Component,Injectable,EventEmitter} from 'angular2/core';

@Injectable()
class KittencupService {
change: EventEmitter;

constructor(){
this.change = new EventEmitter();
}
}

@Component({
selector: 'child',template: `

child {{i}}

` }) class Child {

public i:number = 0;

constructor(public service:KittencupService){

service.change.subscribe((value:number)=>{
  this.i = value;
})

}
}

@Component({
selector: 'App',template: `

App {{i}}

` }) export class App {

i:number = 0;

constructor(service:KittencupService) {
setInterval(()=> {
service.change.emit(++this.i);
},1000)
}

}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持编程之家。

原文地址：https://www.jb51.cc/js/38431.html