angular2组件间是可以相互传递参数的，可以通过子组件传递到父组件，也可以由父组件传递到子组件，也可以由子组件传递到父组件，然后再传递到其他子组件。
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: `
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
import {Output,EventEmitter,Component} from 'angular2/core';
@Component({
selector: 'child',
template: `
child
`
})
class Child {
@Output() updateNumberI:EventEmitter
i:number = 0;
constructor() {
setInterval(()=> {
this.updateNumberI.emit(++this.i);
}, 1000)
}
}
@Component({
selector: 'App',
directives: [Child],
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
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',
directives: [Child],
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
import {ViewChild,Component} from 'angular2/core';
@Component({
selector: 'child',
template: `
child {{i}}
`
})
class Child {
i:number = 0;
}
@Component({
selector: 'App',
directives: [Child],
template: `
App {{i}}
`
})
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: `
child {{service.i}}
`
})
class Child {
constructor(public service:KittencupService){
}
}
@Component({
selector: 'App',
directives: [Child],
providers: [KittencupService],
template: `
App {{i}}
`
})
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: `
child {{i}}
`
})
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: `
App {{i}}
`
})
export class App {
i:number = 0;
constructor(service:KittencupService) {
setInterval(()=> {
service.change.emit(++this.i);
}, 1000)
}
}
转自：https://github.com/kittencup/angular2-ama-cn/issues/23