什么是 Angular 2 中的 change
事件?什么时候发货,如何使用?
IE。我通过 (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;
}
}
最佳答案
这就是事件冒泡:change
发生在 input
上,然后通过 dom 树冒泡并在 inner-component
元素上得到处理。可以通过记录事件来检查它:
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;
}
}
关于typescript - 什么是 Angular 2 中的 `change` 事件,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/38227838/