Question

我有firebase数据库，并尝试通过angular检索数据库。能够连接到数据库，但是，无法读取数据...这是我所做的并且无法获取数据...

我肯定会丢失一些东西，任何人都可以指导或提供链接吗？

import { Component } from '@angular/core';
import { Observable } from 'rxjs/Observable';

import {AngularFirestore, AngularFirestoreCollection, AngularFirestoreDocument} from 'angularfire2/firestore';
import { Http } from '@angular/http';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent {
  private itemsCollection: AngularFirestoreCollection<UserProfiles>;
  items: Observable<UserProfiles[]>;
  constructor(private afs: AngularFirestore) {
    this.itemsCollection = afs.collection<UserProfiles>('UserProfiles');
    this.items = this.itemsCollection.valueChanges();
  }

}

export class UserProfiles{
  id?: string;
  active?: string;
  company?: string;
  email?: string;
  firstName?: string;
  lastName?: string;
  password?: string;
  userId?: string;
  userType?: string;
}

Answer 1

您需要针对subscribe()创建的Observable<UserProfiles[]>;（在这种情况下为valueChanges()()类属性）items进行检索/使用数据：

import { Component } from '@angular/core';
import { Observable } from 'rxjs/Observable';

import {AngularFirestore, AngularFirestoreCollection, AngularFirestoreDocument} from 'angularfire2/firestore';
import { Http } from '@angular/http';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent {
  private itemsCollection: AngularFirestoreCollection<UserProfiles>;
  items: Observable<UserProfiles[]>;
  constructor(private afs: AngularFirestore) {
    this.itemsCollection = afs.collection<UserProfiles>('UserProfiles');
    this.items = this.itemsCollection.valueChanges();
    this.items.subscribe(data => console.log(data)); // subscribe and log emitted data
  }

}

否则，如果您在模板中使用items，作为一种选择，您可以利用async管道来订阅items的可观察对象并呈现数据：

<ul>
  <li *ngFor="let item of items | async">{{item.someProperty}}</li>
</ul>

希望有帮助！

检索firestore集合，使用angular4文档

1 个答案: