每當(dāng)我嘗試創(chuàng)建新票時(shí)，都會(huì)收到以下錯(cuò)誤消息：無(wú)法讀取未定義的屬性“id”這是我的 thread.service.ts，其中有用于創(chuàng)建票證的 AddTicket 方法： addTicket(id: string,heading: string,user: string,date: Date,description: string,likeCount: number,timeLeft: number){  const newTicket = new Threads  (    id,    heading,    user,    new Date(date),    description,    likeCount,    timeLeft  );  let generatedId: string;  return this.http  .post<{ name: string }>(    'https://ionic-angular-a0570.firebaseio.com/all-tickets.json',    {      ...newTicket,      id: Math.random().toString()    }  )  .pipe(    switchMap(resData => {      generatedId = resData.name;      return this.tickets;    }),    take(1),    tap(tickets => {      newTicket.id = generatedId;      this._tickets.next(tickets.concat(newTicket));    })  );}我正在調(diào)用 new-thread.page.ts 中的方法：  onCreateTicket(){this.threadService.addTicket(this.threads.id, this.heading, this.registerService.user, this.threadService.getDate(), this.description, +this.threadService.getLikes(), +12).subscribe();如果有幫助，這是我的threads.model.ts：export class Threads {constructor(    public id: string,    public heading: string,    public user: string,    public date: Date,    public description: string,    public likeCount: number,    public timeLeft: number){}}新線(xiàn)程.page.ts：import { Component, OnInit } from '@angular/core';import { ThreadsService } from '../main/departmentforum/threads/threads.service';import { NavController } from '@ionic/angular';import { RegisterService } from '../register/register.service';import { Threads } from '../main/departmentforum/threads/threads.model';@Component({  selector: 'app-new-thread',  templateUrl: './new-thread.page.html',  styleUrls: ['./new-thread.page.scss'],})export class NewThreadPage implements OnInit {  heading: string;  description: string;  businessforum: string;  departmentforum: string;  threads: Threads;  constructor(private navController: NavController, private threadService: ThreadsService, public registerService: RegisterService) {}  ngOnInit() {  }