角4 - 观察属性变化的变量

我想观看json的嵌套属性。每当此嵌套属性更改时调用fn（）。角4 - 观察属性变化的变量

export class HeaderComponent { 
    user: any; 

    constructor(){ 
    this.user = { 
     options: [ 
     { name: 'Jenny Hess', img: 'assets/img/avatar/small/jenny.jpg' }, 
     { name: 'Elliot Fu', img: 'assets/img/avatar/small/elliot.jpg' }, 
     { name: 'Stevie Feliciano', img: 'assets/img/avatar/small/stevie.jpg' } 
     ], 
     selected: { name: 'Jenny Hess', img: 'assets/img/avatar/small/jenny.jpg' } 
    } 
    }

FN变化值

public changeUser(item) { 
    this.user.selected = item; 
    /*Some Code here*/ 
} 

    public customLogin(user) { 
     /*Some Code here*/ 
     this.user.selected = user; 
     /*Some Code here*/ 
}

每当this.user.selected变化值调用一个函数。我也使用rxjx。

任何建议？

来源

2017-07-12 Sumit Ridhal

'HeaderComponent'是否需要监视值或其他组件（父组件）？ –

@ ADreNaLiNe-DJ通过函数在'HeaderComponent'中更改'this.user.selected'的编号值。 –

提供更多信息，以何种方式改变。你可以尝试'ngDoCheck'。 –

你可以做这样的事情：

export class HeaderComponent implements OnDestroy { 
    user: any; 
    userSelectSubject: BehaviorSubject<{name: string, img: string}>; 
    private userSelectSubscription: Subscription; 

    constructor(){ 
    this.user = { 
     options: [ 
     { name: 'Jenny Hess', img: 'assets/img/avatar/small/jenny.jpg' }, 
     { name: 'Elliot Fu', img: 'assets/img/avatar/small/elliot.jpg' }, 
     { name: 'Stevie Feliciano', img: 'assets/img/avatar/small/stevie.jpg' } 
     ] 
    } 

    this.userSelectSubject = new BehaviorSubject<{name: string, img: string}>({ name: 'Jenny Hess', img: 'assets/img/avatar/small/jenny.jpg' }); 

    this.userSelectSubscription = this.userSelectSubject.subscribe((newSelectedUser) => { 
     this.user.selected = newSelectedUser; 
    }); 
    } 

    ngOnDestroy() { 
    this.userSelectSubscription.unsubscribe(); 
    } 
}

然后你只需要调用this.userSelectSubject.next({...})传递新的选择的用户作为参数。

来源

2017-07-12 14:21:54 Giovane

谢谢@Giovane它帮助 –

角4 - 观察属性变化的变量

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