如何在app.module中的服务内部调用方法-Angular

Question

我在服务中具有以下功能：

export class DualLogonService {
  url: string;
  constructor(private router: Router) {}

  saveURL(): void {
    this.url = this.router.url;
  }
}

应用模块

import { DualLogonService } from './ dual-logon/dual-logon.service';
...
export function saveUrl(dualLogonService: DualLogonService, router: Router) {
  console.log(router.url);TypeError: Cannot read property 'url' of undefined
  return dualLogonService.saveURL();//TypeError: Cannot read property 'saveURL' of undefined
}


{
  provide: APP_INITIALIZER,
  deps: [DualLogonService],
  useFactory: saveUrl,
  multi: true
}

如果我在服务中执行以下操作，则可以在app.module中访问该函数，但不能使用this.router.url ：

export function saveURL() {
   this.url = this.router.url;
}

Answer 1

  //This function should be above the @ngModel decorator
  export function callSaveUrl(dualLogonService: DualLogonService) {
       //Do what you need here
       return (): Promise<any> => { 
         return dualLogonService.saveUrl();
        }
  }


 DualLogonService,
 { provide: APP_INITIALIZER,useFactory: callSaveUrl, deps: [DualLogonService], multi: true}

试试这样的东西，它未经测试，但我认为这是您正在寻找的

从更改您的代码

{
 provide: APP_INITIALIZER,
 deps: [DualLogonService],
 useFactory: saveUrl,
 multi: true
}

对此

DualLogonService,
{ provide: APP_INITIALIZER,useFactory: callSaveUrl, deps: [DualLogonService], multi: true}