NgZone/Angular2/Ionic2 TypeError：无法读取未定义的属性“运行”

Posted 2023-03-13

【中文标题】NgZone/Angular2/Ionic2 TypeError：无法读取未定义的属性“运行”

【英文标题】：NgZone/Angular2/Ionic2 TypeError: Cannot read property 'run' of undefined

【发布时间】：2016-12-20 15:02:27

【问题描述】：

我收到此错误 TypeError: Cannot read property 'run' of undefined in Subscriber.js:229 并且不知道为什么 - 在 ionic beta 10 中，此代码运行良好...在 11 没有。

import Component, NgZone from '@angular/core';
import NavController from 'ionic-angular';

declare var io;

@Component(
  templateUrl: 'build/pages/home/home.html'
)    
export class HomePage 
    static get parameters() 
        return [NgZone];
    

    zone: any;
    chats: any;
    chatinp: any;
    socket: any;

constructor(public navCtrl: NavController, ngzone) 
    this.zone = ngzone;
    this.chats = [];
    this.chatinp ='';
    this.socket = io('http://localhost:3000');
    this.socket.on('message', (msg) => 
        this.zone.run(() => 
            this.chats.push(msg);
        );
    );


send(msg) 
    if(msg != '')
        this.socket.emit('message', msg);
    
    this.chatinp = '';
   

【参考方案1】：

而不是像这样注入它：

static get parameters() 
  return [NgZone];

你为什么不这样做：

import  Component, NgZone  from "@angular/core";

@Component(
  templateUrl:"home.html"
)
export class HomePage 

  public chats: any;

  constructor(private zone: NgZone) 

    this.chats = [];
    let index: number = 1;

    // Even though this would work without using Zones, the idea is to simulate
    // a message from a socket.
    setInterval(() =>  this.addNewChat('Message ' + index++); , 1000);
  

  private addNewChat(message) 
    this.zone.run(() => 
        this.chats.push(message);
    );
  

我将private zone: NgZone 添加为constructor 中的参数，然后我可以通过使用zone 变量来使用run() 方法，如下所示：

this.zone.run(() => 
  // ... your code
);