我正在使用Ionic 2,其中一个组件有两个组件,数据是使用 Launcher 共享的 . 但是当我执行程序时,就出现了这个错误 .
运行时错误未捕获(在承诺中):TypeError:无法读取未定义的属性'BillNo'TypeError:无法读取Object.eval中未定义的属性'BillNo'[as updateDirectives]
这是我的代码:
bill-settlement.html
...
<page-bill-list (BillSelected)="onBillSelected($event)"></page-bill-list>
...
<page-bill-details [billItem]="billItem"></page-bill-details>
...
bill-settlement.ts
@Component({
selector: 'page-bill-settlement',
templateUrl: 'bill-settlement.html',
})
export class BillSettlement {
...
billItem: BillDetail
...
onBillSelected(billData: BillDetail) {
this.billItem = billData
}
}
bill-list.html
<ion-buttons>
<button ion-button *ngFor="let item of billItems" (click)="getBillDetails(item)">
{{item.BillNo}}
</button>
</ion-buttons>
bill-list.ts
@Component({
selector: 'page-bill-list',
templateUrl: 'bill-list.html',
})
export class BillList {
billItems: BillDetail[] = []
billItem = new BillDetail()
@Output() BillSelected = new EventEmitter<BillDetail>()
constructor(public navCtrl: NavController,
public navParams: NavParams,
public billSrv: BillerService,
public authSrv: AuthService,
public genSrv: GenericService) {
this.billSrv.getBills()
.subscribe(data => {
this.billItems = data
})
}
getBillDetails(item: BillDetail) {
this.BillSelected.emit(this.billItem)
}
}
bill-details.ts
@Component({
selector: 'page-bill-details',
templateUrl: 'bill-details.html',
})
export class BillDetails {
...
@Input() billItem: BillDetail
...
}
bill-details.html
...
<ion-input text-right type="text" [value]="billItem.BillNo" readonly></ion-input> //billItem model has BillNo property
...
问题是 billItem.BillNo
在 bill-details.ts
中最初没有值,只有在我单击 bill-list.html
中的帐单编号按钮时才会定义它 . 如何最初定义billItem,然后在使用bill number按钮单击时替换 .
1 回答
在设置
billItem
之前加载视图 .您可以使用安全导航操作符
?
.或者在 bill-details.ts 的构造函数中将其设置为空对象: