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  • angular2组件通讯

    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)
        }
    
    }
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  • 原文地址:https://www.cnblogs.com/XIE7654/p/6568024.html
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