Angular 2中的变化事件是什么？什么时候发送,我该如何使用它？
I. e.通过(change)=“update()”在以下代码中订阅了什么？
I. e.通过(change)=“update()”在以下代码中订阅了什么？
http://plnkr.co/edit/mfoToOSLU6IU2zr0A8OB?p=preview
import {Component,View,Input,Output,EventEmitter,OnChanges} from '@angular/core'
@Component({
selector: 'inner-component',template: `
<label><input type="checkBox" [(ngModel)]="data.isSelected"> Selected</label>
`
})
export class InnerComponent {
data = { isSelected: false };
}
@Component({
selector: 'my-app',template: `
<p><inner-component (change)="update()"></inner-component></p>
<p>The component was updated {{count}} times</p>
`,directives: [InnerComponent]
})
export class AppComponent {
count = 0;
update() {
++this.count;
}
}
这是冒泡的事件：输入发生变化,然后是dom树的气泡,并在内部组件元素上处理.可以通过记录事件来检查：
http://plnkr.co/edit/J8pRg3ow41PAqdMteKwg?p=preview
@Component({
selector: 'my-app',template: `
<p><inner-component (change)="update($event)"></inner-component></p>
<p>The component was updated {{count}} times</p>
`,directives: [InnerComponent]
})
export class AppComponent {
count = 0;
update($event) {
console.log($event,$event.target,$event.currentTarget);
++this.count;
}
}
