Angular2的双向数据绑定 [英] Two-Way Data-Binding with Angular2
本文介绍了Angular2的双向数据绑定的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
有人知道我在做什么错吗?我无法使用[[ngModel)]语法使Angular2 2路数据绑定正常工作.这是我的组件:
Does anybody know what I'm doing wrong here? I'm unable to get Angular2 2-way data-binding to work using the [(ngModel)] syntax. Here's my Component:
import { Component } from '@angular/core';
import { FormsModule } from '@angular/forms';
declare let window;
@Component({
templateUrl: 'tabs.html'
})
export class TabsPage {
progress: number;
constructor(public _sharedService: SharedService) {
window.addEventListener('progress.update', function () { # ANSWER: Change function () { to () => {
this.progress = window.sharedService.progress;
console.log(this.progress); # this outputs numbers
});
}
}
这是我的HTML:
<ion-range [(ngModel)]="progress" min="0" max="100" name="progress">
<ion-icon range-left small name="sunny"></ion-icon>
<ion-icon range-right name="sunny"></ion-icon>
</ion-range>
因为我正在使用[[ngModel)],所以不应该更改Component内部的this.progress的值反映在视图中吗?
Shouldn't changing the value of this.progress inside the Component reflect in the view since I'm using [(ngModel)]?
推荐答案
对于双向绑定,您需要一个 @Input()
和 @Output()
,其中名称匹配而 @Output()
的名称具有一个附加的 Change
后缀.
For two-way-binding you need an @Input()
and and @Output()
where the name matches while the @Output()
s name has an additional Change
suffix.
@Component({
templateUrl: 'tabs.html'
})
export class TabsPage {
@Input()
progress: number;
@Output()
progressChange:EventEmitter<number> = new EventEmitter<number>();
constructor(public _sharedService: SharedService) {
window.addEventListener('progress.update', () => { // <<<=== use arrow function for `this.` to work
this.progress = window.sharedService.progress;
this.progressChange.emit(this.progress);
console.log(this.progress); # this outputs numbers
});
}
}
对于事件处理程序,您也可以使用
for the event handler you can also use
@Component({
templateUrl: 'tabs.html'
})
export class TabsPage {
@Input()
progress: number;
@Output()
progressChange:EventEmitter<number> = new EventEmitter<number>();
constructor(public _sharedService: SharedService) {}
@HostListener('window:progress.update')
onProgressUpdate() {
this.progress = window.sharedService.progress;
this.progressChange.emit(this.progress);
console.log(this.progress); # this outputs numbers
}
}
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