组件之间的共享可以有好几种方式
父->子 input 方式
@Component({
selector: 'App',directives: [Child],template: `
App
i:number = 0;
constructor() {
setInterval(()=> {
this.i++;
},1000)
}
}
子->父 output 方式
selector: 'child',template: `
child
` }) class Child { @Output() updateNumberI:EventEmitterconstructor() {
setInterval(()=> {
this.updateNumberI.emit(++this.i);
},1000)
}
}
@Component({
selector: 'App',template: `
App {{i}}
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
selector: 'child',template: `
child
` }) class Child {constructor(@Host() @Inject(forwardRef(()=> App)) app:App) {
setInterval(()=> {
app.i++;
},1000);
}
}
@Component({
selector: 'App',template: `
App {{i}}
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
@Component({
selector: 'App',template: `
App {{i}}
@ViewChild(Child) child:Child;
ngAfterViewInit() {
setInterval(()=> {
this.child.i++;
},1000)
}
}
service 方式
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}}
constructor(service:KittencupService) {
setInterval(()=> {
service.i++;
},1000)
}
}
service EventEmitter方式
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}}
i:number = 0;
constructor(service:KittencupService) {
setInterval(()=> {
service.change.emit(++this.i);
},1000)
}
}