我有一个选择器，可让用户更改所选的付款方式。这称为一个名为PaymentComponent的组件，它“应该”监听父组件中Selector的更改，然后切换相应的支付方法组件（即WireTransferPayment，CheckPayment，CreditCardPayment），但现在不起作用。事实上，PaymentComponent甚至没有注册选择器已经改变。我还在学习Angular2所以我意识到我仍然缺少一些简单的东西。有人能指出我正确的方向吗？我的google foo现在让我失望了。
print(format(MyArray_precise[0], '.64'))
# 0.442000000000000003996802888650563545525074005126953125
答案 0 :(得分：0)
所以，我找到了解决方案，import {Component, OnInit, Input, OnChanges, SimpleChange} from '@angular/core';
@Component({
moduleId: module.id,
selector: 'app-payment',
templateUrl: 'payment.component.html',
styleUrls: ['payment.component.css'],
directives: [
CheckPaymentComponent,
WireTransferPaymentComponent
],
})
export class PaymentComponent implements OnInit, OnChanges {
@Input() name: string;
changeLog: string[] = [];
ngOnChanges(changes: {[propkey: string]: SimpleChange}) {
let log: string[] = [];
console.log('log ', log);
for (let propName in changes) {
console.log('propName ', propName);
let changedProp = changes[propName];
let from = JSON.stringify(changedProp.previousValue);
let to = JSON.stringify(changedProp.currentValue);
log.push( `${propName} changed from ${from} to ${to}`);
}
this.changeLog.push(log.join(', '));
}
constructor() {
}
ngOnInit() {
}
}
就是我所需要的。
{site:randomNumber(min: 1, max:10)}