详解Angular2组件之间如何通信

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: `

`

})

class Child {

@Input() content:string;

}

@Component({

selector: 'App',

directives: [Child],

template: `

`

})

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: `

`

})

class Child {

@Output() updateNumberI:EventEmitter = new EventEmitter();

i:number = 0;

constructor() {

setInterval(()=> {

this.updateNumberI.emit(++this.i);

}, 1000)

}

}

@Component({

selector: 'App',

directives: [Child],

template: `

`

})

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: `

`

})

class Child {

constructor(@Host() @Inject(forwardRef(()=> App)) app:App) {

setInterval(()=> {

app.i++;

}, 1000);

}

}

@Component({

selector: 'App',

directives: [Child],

template: `

`

})

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: `

`

})

class Child {

i:number = 0;

}

@Component({

selector: 'App',

directives: [Child],

template: `

`

})

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: `

`

})

class Child {

constructor(public service:KittencupService){

}

}

@Component({

selector: 'App',

directives: [Child],

providers: [KittencupService],

template: `

`

})

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;

constructor(){

this.change = new EventEmitter();

}

}

@Component({

selector: 'child',

template: `

`

})

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: `

`

})

export class App {

i:number = 0;

constructor(service:KittencupService) {

setInterval(()=> {

service.change.emit(++this.i);

}, 1000)

}

}

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