Angular服务未将数据分配给局部变量[duplicate]

Question

此问题已经在这里有了答案：

How do I return the response from an Observable/http/async call in angular?（9个答案）

已关闭现在。

我正在尝试使用GET请求来接收要放入本地变量的数据。如果这在subscibe代码内，我已经能够获取本地变量以在控制台admin中显示其数据。但是，当我将console.log放在外面时，它不起作用。为什么“ this.taskSchedule”没有显示在控制台中？

export class TestTaskComponent implements OnInit {
  profileForm: FormGroup;

  taskSchedule: any = {};


  constructor(
    private taskScheduleService: TaskScheduleService,
    private stateStorageService: StateStorageService,
    private router: Router) { }

  ngOnInit() {
    this.taskId = this.stateStorageService.getCurrentTaskId();

    this.taskScheduleService.getTaskSchedule(19).subscribe(data => {
      this.taskSchedule = data;
    });
    console.log(this.taskSchedule);
  }
}

在控制台输出中，它只是说“未定义”。它应该输出API数据

Answer 1

因为您正在尝试在异步的预订块之后访问它。通读我的评论。

ngOnInit() {
    // This is an asynchronous function
    this.taskScheduleService.getTaskSchedule(19).subscribe(data => {
      this.taskSchedule = data;
      // Here you can access this.taskSchedule
    });
    // This is where the subscribe block ends so when you try to console this.taskSchedule you will find it empty or not yet assigned
    console.log(this.taskSchedule);
}