Question

如何访问escope以外的变量？

导出类ClientsComponent实现OnInit { title：string =“所有客户”

clients: Client[] = [];
response: any;
total_clients: number;
total_pages: number;
pages: any[] = [];

constructor( private _clientService: ClientService ) {}

ngOnInit() {

   this._clientService.getData()
        .subscribe(
        data => this.response = data,
        err => console.error(err),
        () => {
            this.clients = this.response.data, 
            this.total_clients = this.response.total
            }
        );


    console.log(this.total_clients); <- i can not access this


}

Answer 1

它不在范围之外，当在控制台中打印this.total_clients时，它还没有填充。所有HTTP请求都是异步操作，因此如果您想要访问它，您可以在订阅中执行此操作，如下所示：

ngOnInit() {

   this._clientService.getData()
        .subscribe(
        data => this.response = data,
        err => console.error(err),
        () => {
            this.clients = this.response.data, 
            this.total_clients = this.response.total
            console.log(this.total_clients); <- this will print your data
            }
        );


    console.log(this.total_clients); <- this is executed before the call is finished, as you will see


}

Answer 2

您需要在构造函数中初始化变量，然后在异步调用的回调中填充它。这是完整的代码：

export class ClientsComponent implements OnInit { title: string = "All Clients"
  clients: Client[] = [];
  response: any;
  total_clients: number;
  total_pages: number;
  pages: any[] = [];

  constructor( private _clientService: ClientService ) {
    this.clients = [];
    this.total_clients = 0l
  }

  ngOnInit() {
    this._clientService.getData()
        .subscribe(
        data => {
          this.clients = this.response.data;
          this.total_clients = this.response.total;
        }
        err => console.error(err)
    );
  }
}

为什么我无法访问变量“total_clients”？

2 个答案: