Question

我无法找到问题的解决方案。我有类设备然后我有DeviceService进行通信。最后，在页面场景我需要创建一个Device数组，但以错误结束。我几乎尝试了一切。

错误如：无法读取属性＆＃39; undefined＆＃39;未定义的; 无法读取属性＆＃39; id＆＃39;未定义的 谢谢你的帮助： - ）

Device.ts

export class Device {
  id: number;
  name: string;
  number: string;
  constructor() { }
  get deviceId(): number {return this.id; }
  get deviceNumber(): string {return this.number; }
  get deviceName(): string {return this.name; }
  set deviceNumber(number: string) {this.number = number; }
  set deviceName(name: string) {this.name = name;}
}

然后我制作了我已添加到提供商的DeviceService 的 DeviceService.ts

import {Injectable} from '@angular/core';
import {Device} from '../providers/device';
@Injectable()
export class DeviceService {
  deviceCount: number;
  devices: Array<Device>;
  constructor(){}
  getDevices(): Array<Device> {
    return this.devices;
  }
  pushDevice(name, number) {
    number.toString();
    this.devices[this.deviceCount].id++;
    this.devices[this.deviceCount].deviceName = name;
    this.devices[this.deviceCount].deviceNumber = number;
    this.deviceCount++;
  }
}

Scene.ts ：我需要创建设备数组

import {Component} from '@angular/core';
import {NavController, NavParams, PopoverController, ModalController} from 'ionic-angular';
import {CreateDevicePage} from '../create-device/create-device';
import {PopoverPage} from '../../providers/popover';
import {DeviceService} from '../../providers/device-service';

@Component({
  selector: 'page-scenes',
  templateUrl: 'scenes.html',
})
export class ScenesPage {
  constructor(public navCtrl: NavController,
              public navParams: NavParams,
              public modalCtrl: ModalController,
              public popoverCtrl: PopoverController,
              public deviceCtrl: DeviceService,
  ) { }
  ionViewDidLoad() { }
  launchSecondPage() {
    let modal = this.modalCtrl.create(CreateDevicePage);
    modal.onDidDismiss((data) => {

      /*Problem here*/
      this.deviceCtrl.pushDevice(data.name, data.number);
    });
    modal.present();
  }
}

Answer 1

pushDevice(name, number) {
    number.toString();
    this.devices[this.deviceCount] = new Device(); // <= add this
    this.devices[this.deviceCount].id++;
    this.devices[this.deviceCount].deviceName = name;
    this.devices[this.deviceCount].deviceNumber = number;
    this.deviceCount++;
}

也代替devices: Array<Device>;使用devices: Device[] = [];

Answer 2

你应该试试这个：

export class Device {
  static ID: number = 0;

  private id: number;
  private name: string;
  private number: string;

  constructor(name: string, number: string) {
    this.id = Device.ID++;
    this.name = name;
    this.number = number;
  }

  public get deviceId() {
    return this.id;
  }

  public set deviceName(value: string) {
    this.name = value;
  }

  public get deviceName(): string {
    return this.name;
  }

  public set deviceNumber(value: string) {
    this.number = value;
  }

  public get deviceNumber() {
    return this.number;
  }
}

和DeviceService.ts

import {Injectable} from '@angular/core';
import {Device} from '../providers/device';

@Injectable()
export class DeviceService {
  private _devices: Device[] = [];

  public get devices() {
    return this._devices.slice();
  }

  public get deviceCount() {
    return this.devices.length;
  }

  constructor(){}

  public pushDevice(name: string, number: string) {
    this._devices = this._devices.concat(new Device(name, number));
  }
}

如果你在你的设置者和你的Device类的getter中没有做任何特别的事情，那就去除它们并使用公共属性：

export class Device {
   static ID: number = 0;

   private id: number;

   public name: string;
   public number: string;

   constructor(name: string, number: string) {
     this.id = Device.ID++;
     this.name = name;
     this.number = number;
   }

   public get deviceId() {
     return this.id;
   }
}

Answer 3

正确的方式

设备

中的

id: number = 0;
name: string;
number: string;
constructor(_id:number,_name:string,_number:string) {
    this.id=_id;
    this.name = _name;
    this.number = _number;
  }

在 DeviceService

中

devices: Array<Device> = []; 
idCount: number = 0;

pushDevice(name: string, number: string) {
    let device = new Device(this.idCount, name, number);
    this.devices.push(device);
    this.idCount++;
 }

对象数组Angular 2

3 个答案:

正确的方式