Angular 5 - 数据未显示在模板中

debugcn 发表于 Dev

达米安

我正在使用 angular 5，并且我正在努力使用可观察对象从休息端点获取数据以显示在我的模板上。

我的组件如下

import { Component, OnInit, Input } from '@angular/core';
import { NewsService } from './news.service';
import { NewsItem } from './newsItem.model';
import { Observable } from 'rxjs';

@Component({
  selector: 'app-news',
  //templateUrl: './news.component.html',
template: `
  <ul>
      <li *ngFor="let newsItem of newsItems">{{newsItem}}</li>
  </ul>
  <h3 *ngIf="newsItems"> {{ newsItems }} </h3> 

  <h3 *ngIf="test"> test: {{ test | async}} </h3>`,
  styleUrls: ['./news.component.css']
})
export class NewsComponent implements OnInit {

  newsItems: NewsItem[];
  test : string;

  constructor(private newsService: NewsService) { 
    this.newsItems = [];
  }

  ngOnInit() {

    this.newsService.getLatestNews().subscribe(
      data => {
        console.log('1 Component Data:', data);
        data.forEach(function (newsItem) {
          console.log('2 Component Data:', newsItem);
        });

        this.newsItems = data;
        this.test = 'Hello';
        console.log('3 Component newsItems:', this.newsItems);
        console.log('4 Component test:', this.test);
      }
    );
  }

}

我的服务如下

import { Injectable } from '@angular/core';
import { HttpClient, HttpHeaders, HttpParams, HttpRequest } from '@angular/common/http';
import 'rxjs';
import { NewsItem } from './newsItem.model';
import { Observable } from 'rxjs';

@Injectable()
export class NewsService {

  newsEndpoint:string = 'http://myendpoint.com/services/news';

  constructor(private httpClient: HttpClient) { }

  getLatestNews(): Observable<NewsItem[]>{
       return this.httpClient.get<NewsItem[]>(this.newsEndpoint, {
          observe: 'body',
          responseType: 'json'
        });
  }

}

数据正在 ngOnInit 方法中打印到控制台，但模板中不会输出任何内容

我正在尝试使用此模板为 sharepoint 框架创建一个角度应用程序 - https://github.com/maliksahil/SPFxAngularCLI

谁能看到我做错了什么？

切拉潘w

使用 ChangeDetectorRef

 constructor(private newsService: NewsService,private cdr:ChangeDetectorRef) { 
    this.newsItems = [];
  }

  ngOnInit() {

    this.newsService.getLatestNews().subscribe(
      data => {
        console.log('1 Component Data:', data);
        data.forEach(function (newsItem) {
          console.log('2 Component Data:', newsItem);
        });

        this.newsItems = data;
        this.cdr.detectChanges()
        this.test = 'Hello';
        console.log('3 Component newsItems:', this.newsItems);
        console.log('4 Component test:', this.test);
      }
    );
  }

}

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