AngularFIRE 属性“订阅"在类型“AngularFireList<{}>"上不存在

问题描述

我正在关注本教程，了解如何将 angular 与 firebase 数据库连接.但在 17:30 分钟，我收到此错误:

I'm following this tutorial about how to connect angular with firebase database. But in minute 17:30 I'm getting this error:

属性订阅"不存在于类型AngularFireList"

我的应用组件:

import { Component } from '@angular/core';
import {AngularFireDatabase, AngularFireDatabaseModule} from 'angularfire2/database';

import {AngularFireAuth, AngularFireAuthModule} from 'angularfire2/auth';
import { Observable } from 'rxjs/Observable';
import * as firebase from 'firebase/app';
import { Country } from './models/country';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})

export class AppComponent {
  countries: any[];

  constructor(db: AngularFireDatabase )
  {
     db.list('/Country/countries')
     .subscribe(countries => { //  <--ERROR IS HERE
      this.countries = countries;
      console.log(this.countries);
      });
  }
}

我的模型:

export class Country {
     // --ATTRIB--
     id: string;
     name: string;
     code: string;
     urlFlag: string;
}

无法找到有关此错误的任何信息.我是角度的初学者.如果可以帮助我，谢谢.

Cant find anything about this error. I'm beginner in angular. Thanks if can help me.

推荐答案

从 AngularFire 5.0 开始，您将需要使用 snapshotChanges()、valueChanges<T>()、stateChanges() 或 auditTrail().请参阅 5.0 迁移指南.

Starting in AngularFire 5.0 you'll want to use one of snapshotChanges(), valueChanges<T>(), stateChanges(), or auditTrail(). See the 5.0 migration guide.

从最基本的开始，valueChanges():

export class AppComponent {
  countries: Observable<Country[]>;
  constructor(db: AngularFireDatabase ) {
    this.countries = db.list('/Country/countries').valueChanges();
  }
}

这篇关于AngularFIRE 属性“订阅"在类型“AngularFireList<{}>"上不存在的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！