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我做一个简单的项目空数组:角2:在组分HTML
有2个输入滑块和按钮“计算”,当按下按钮时,计算完成和印刷到表中。
我有一个小问题,当我按下按钮时,表组件显示答案数组是空的,但如果我从构造函数将它打印到控制台,一切都会显示出来。
有人可以帮忙吗? 我想做一个*ngFor
并稍后循环遍历元素。
服务:
@Injectable()
export class DataService {
loanArray: Payment[] = [];
setCalculatedPayments(loanSum: number, loanTime:number) {
this.loanArray = new PaymentsCalculated(loanSum, loanTime).calculateLoanDetails();
}
getCalculatedPayments() {
return this.loanArray;
}
}
贷款部分:
export class LoanTablesComponent implements OnInit {
loanArray: Payment[] = []; // is it always empty?
constructor(private DataService: DataService) {
this.loanArray = this.DataService.getCalculatedPayments();
// here it prints the loanArray as required
// but if I print out in the .html, it is always zero
}
ngOnInit() {
}
}
计算部件:
export class CalculatorComponent implements OnInit {
loanSum: number;
loanTime: number;
constructor(private DataService: DataService) {
setTimeout(() => this.loanSum = 500);
setTimeout(() => this.loanTime = 1);
// for input sliders
}
ngOnInit() {
}
calculatePayments(): void{
this.DataService.setCalculatedPayments(this.loanSum, this.loanTime);
}
}
感谢您的帮助,刚开始学习和寻求建议(:
'CalculatorComponent'和'LoanTablesComponent'之间的关系是什么? – AngularChef
计算器显示用于计算的输入的输入UI,当按下按钮时它将数据提供给数据服务,贷款表输出表,从数据服务中取数据 –
好的。但我的意思是他们如何在组件树**中关联**? (例如,是否是另一个的孩子?)看起来你有一个时间问题:一旦'LoanTablesComponent'实例化,你尝试读取数据,但直到你调用setCalculatedPayments()'它才被设置。如果'loanArray'包含非原始值,我认为变更检测不能用于您的设置。也许尝试用[get property](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/get)替换'LoanTablesComponent'中的'loanArray'? – AngularChef