1. 确认服务中是否正确返回数据，并且数据类型与组件中需要的数据类型一致。
2. 在组件中使用订阅来获取异步的数据。示例代码如下：

服务中返回数据

import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { Observable } from 'rxjs';

@Injectable()
export class DataService {
  private dataUrl = 'url_to_data';

  constructor(private _http: HttpClient){}

  getData(): Observable {
    return this._http.get(this.dataUrl);
  }
}

组件中获取异步数据

import { Component, OnInit } from '@angular/core';
import { DataService } from './data.service';

@Component({
  selector: 'app-data',
  template: `
    
Data
    

      
{{ item.property }}
    
  `
})
export class DataComponent implements OnInit {
  data: any[];

  constructor(private _dataService: DataService) {}

  ngOnInit() {
    this._dataService.getData().subscribe(
      data => {
        this.data = data;
      },
      err => console.error(err),
      () => console.log('done loading data')
    );
  }
}