如何用angular2

Question

Hello All我面临一些承诺和处理500内部服务器错误的问题我已经创建了一个Promises来处理post和获取服务但是当我收到500响应时我无法在烤面包机中显示它是我的代码。

var toasterService: ToasterService;

constructor(toasterService: ToasterService) {
  this.toasterService = toasterService;
}

postService(url: string, bodyParam: any): Promise < any > {
  return this.http
    .post(url, bodyParam, this.options)
    .toPromise()
    .then()
    .catch(this.handleError);
}

private handleError(error: any): Promise < any > {
  let toast;
  toast = {
    type: 'info',
    title: 'Data Zone',
    body: 'Data Zone Failure!',
    showCloseButton: boolean
  };
  this.toasterService.pop(toast);
  return Promise.reject(error.message || error);
}

但是在这段代码中

this.toasterService.pop(toast);

这里是stacktrace

Uncaught (in promise): TypeError: Cannot read property 'toasterService' 
of undefined
TypeError: Cannot read property 'toasterService' of undefined

它显示为未定义。我做错了什么，另一件事如何展示烤面包机以防止陷入困境。

Answer 1

你不必为toastservice设置一个变量，带来toastservice＆＃39;在构造函数中足以使用＆＃39; this＆＃39;。

来引用它

您还需要将http导入构造函数。

constructor(toasterService: ToasterService, http: HttpClient) { }

postService(url: string, bodyParam: any): Promise < any > {
   return this.http
      .post(url, bodyParam, this.options)
      .toPromise()
      .then()
      .catch(this.handleError);
}

private handleError(error: any): Promise < any > {
      let toast;
      toast = {
        type: 'info',
        title: 'Data Zone',
        body: 'Data Zone Failure!',
        showCloseButton: boolean
      };
      this.toasterService.pop(toast);
      return Promise.reject(error.message || error);
}