與屬性相反,事件從組件的內部流出,用來通知外部世界發生了一些事情:javascript
在Angular2中爲組件增長事件接口也很是簡單:定義一個事件源/EventEmitter, 而後經過Component註解的events接口包括出來:html
1 //EzCard 2 @Component({ 3 events:["change"] 4 }) 5 class EzCard{ 6 constructor(){ 7 this.change = new EventEmitter(); 8 } 9 }
上面的代碼將組件EzCard的事件源change暴露爲同名事件,這意味着在調用者EzApp組件的模板中,能夠直接使用小括號語法掛接事件監聽函數:java
1 //EzApp 2 @View({ 3 template : "<ez-card (change)="onChange()"></ez-card>" 4 })
每次EzCard觸發change事件時,EzApp的onChange()方法都將被調用。bootstrap
1 <!doctype html> 2 <html> 3 <head> 4 <meta charset="utf-8"> 5 <title>hello,angular2</title> 6 <script type="text/javascript" src="lib/system@0.16.11.js"></script> 7 <script type="text/javascript" src="lib/angular2.dev.js"></script> 8 <script type="text/javascript" src="lib/system.config.js"></script> 9 </head> 10 <body> 11 <ez-app></ez-app> 12 13 <script type="module"> 14 import {Component,View,bootstrap,EventEmitter} from "angular2/angular2"; 15 16 //根組件 - EzApp 17 @Component({selector:"ez-app"}) 18 @View({ 19 directives:[EzCard], 20 template:` 21 <div class="ez-app"> 22 <h1>EzApp</h1> 23 <ez-card (change)="onChange($event)"></ez-card> 24 <pre>{{evtStr}}</pre> 25 </div>` 26 }) 27 class EzApp{ 28 constructor(){ 29 this.evtStr 30 } 31 onChange(evt){ 32 console.log("sth. occured"); 33 this.evtStr = JSON.stringify(evt,null,"\t"); 34 } 35 } 36 37 //具備事件接口的組件 - EzCard 38 @Component({ 39 selector:"ez-card", 40 events:["change"] 41 }) 42 @View({ 43 template : `<div class='ez-card'> 44 My name is <b>{{name}}</b>, 45 I am from <b>{{country}}</b>.</div>` 46 }) 47 class EzCard{ 48 constructor(){ 49 this.name = "Mike"; 50 this.country = "Sweden"; 51 this.change = new EventEmitter(); 52 //模擬觸發事件 53 setTimeout(()=>this.change.next({ 54 src:"EzCard", 55 desc:"模擬事件" 56 }),1000); 57 } 58 } 59 60 //渲染組件 61 bootstrap(EzApp); 62 </script> 63 </body> 64 </html>