我有三個變量，我創建了一個數組并將所有這三個變量推送到這個數組中。在我的 html 模板中，我使用了一個表格。我試過 *ngFor 但它不起作用，我也試過字符串插值，但也不起作用。我收到一個錯誤，叫做 <--can not read property "title" of undefined-->在我的控制臺中，我正在獲取這樣的數據....array of data(3)[{...}{...}{...}]0:{key:"-LtZprPfMtDgzuxmaI5o"}1:{price:1}2:{title:"title1"}array of data(3)[{...}{...}{...}]0:{key:"-LtcY8_6dd8fzibK9EYV"}1:{price:2}2:{title:"title2"}array of data(3)[{...}{...}{...}]0:{key:"-LtcZF9NHknDZ0OcKzHg"}1:{price:3}2:{title:"title3"}這里是我的 product.component.tsimport { ProductsService } from './../../products.service';import { Component, OnInit } from '@angular/core';import { AngularFireDatabase, AngularFireAction, DatabaseSnapshot } from 'angularfire2/database';@Component({  selector: 'app-admin-products',  templateUrl: './admin-products.component.html',  styleUrls: ['./admin-products.component.css']})export class AdminProductsComponent{  constructor(    private products:ProductsService,    private db : AngularFireDatabase    ) {     products.getAll().on('child_added',function(c){        let data = c.val();        let key = c.key;        let price = data.price;        let title = data.title;        let array=[];        array.push({"key":key});        array.push({"title":title});        array.push({"price":price});        console.log('array of data',array);    })      }}還有我的 admin-products.component.html<table class="table">    <thead>        <th>Title</th>        <th>Price</th>        <th></th>    </thead>    <tbody *ngFor="let p of array">        <td>{{p.title}}</td>        <td>{{p.price}}</td>        <td ><a [routerLink]="['/admin/products',p.key]">Edit</a></td>    </tbody></table>