看不到值来自服务的变量的出价答案

【问题标题】：Biding on a variable which value comes from a service can't be seen看不到值来自服务的变量的出价
【发布时间】：2021-10-03 19:33:39
【问题描述】：

一开始，我使用了一个服务，它给了我一个字符串，我将它保存在变量中，并使用大括号在 HTML 上显示它，但我没有看到值，我已经测试了服务和值来自后端，所以我认为这种情况是由于生命周期。我尝试了ngOnInit 和ngAfterViewInit，但我无法获得价值。

elCodigoInterno: string;

  ngOnInit() {
    this.iniciarFormulario();   

    this.dataService.getCodigoInterno().subscribe(
      //result => this.colaborador.codigoInterno = result,
      result => this.elCodigoInterno = result,
      error => console.log('error ', error)
    );       
  }

  ngAfterViewInit(){
    this.dataService.getCodigoInterno().subscribe(
      //result => this.colaborador.codigoInterno = result,
      result => this.elCodigoInterno = result,
      error => console.log('error ', error)
    ); 
  }

<label for="codigoInterno">Código Interno </label>      
<p>{{elCodigoInterno}} </p>

【问题讨论】：

标签： angular binding livecycle

【解决方案1】：

如果你在dataService中创建一个公共变量，然后在getCodigoInterno方法中赋值给这个变量，就可以得到你想要得到的值。

我可以举个例子

///// 服务

export class LocationService {
  public locationlist: Location[] | any;
  public location: Location | any;
  constructor(private http: HttpClient) { }


  public getAllLocation(): Observable<Location[]> {
    return this.http.get<ApiResponse>(environment.locationApiUrl, {}).pipe(
      map(
        (response: ApiResponse) => {
          return this.locationlist = response.content;
        }
      )
    );
  }
}

///// 组件

 public location;
      constructor(private locationService: LocationService) { }
    
      ngOnInit(): void {
        this.location = this.locationService.locationlist[0].id;
      }
      public getAlllocations() {
      this.locationService.getAllLocation().subscribe(location => {
      ...
      });
   }

【讨论】：