【发布时间】：2019-08-09 08:19:09
【问题描述】：
我试图在 LoginService 中注入 AccountService 但它不会，accountService 未定义但另一方面 authServiceProvider 已定义。
相反，它完美地注入了footerComponent。
那么为什么 AccountService 被完美地注入到 FooterComponent 中并且它在 LoginService 中出现了错误。
我不知道问题出在哪里。
import { Injectable } from '@angular/core';
import { AccountService } from 'app/core/auth/account.service';
import { AuthServerProvider } from 'app/core/auth/auth-jwt.service';
@Injectable({ providedIn: 'root' })
export class LoginService {
constructor(public accountService: AccountService, private authServerProvider: AuthServerProvider) {
console.log(this.accountService); // is undefined
console.log(this.authServerProvider); // is defined
}
这是 AuthentificationService
@Injectable({ providedIn: 'root' })
export class AuthServerProvider {
constructor(private http: HttpClient, private $localStorage: LocalStorageService, private $sessionStorage: SessionStorageService) {}
这是 AccountService
@Injectable({ providedIn: 'root' })
export class AccountService {
private userIdentity: any;
private authenticated = false;
private authenticationState = new Subject<any>();
constructor(private languageService: JhiLanguageService, private sessionStorage: SessionStorageService, private http: HttpClient) {}
我尝试在其他组件中使用 AccountService 并完美注入
import { Component } from '@angular/core';
import { AccountService } from 'app/core';
@Component({
selector: 'jhi-footer',
templateUrl: './footer.component.html',
styleUrls: ['./footer.component.scss']
})
export class FooterComponent {
constructor( private accountService: AccountService) {
console.log(this.accountService); // It is defined
}
}
这是 app.module.ts
import './vendor.ts';
import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { HTTP_INTERCEPTORS } from '@angular/common/http';
import { NgbDatepickerConfig } from '@ng-bootstrap/ng-bootstrap';
import { Ng2Webstorage } from 'ngx-webstorage';
import { NgJhipsterModule } from 'ng-jhipster';
import { AuthInterceptor } from './blocks/interceptor/auth.interceptor';
import { AuthExpiredInterceptor } from './blocks/interceptor/auth-expired.interceptor';
import { ErrorHandlerInterceptor } from './blocks/interceptor/errorhandler.interceptor';
import { NotificationInterceptor } from './blocks/interceptor/notification.interceptor';
import { SharedModule } from 'app/shared';
import { CoreModule } from 'app/core';
import { AppRoutingModule } from './app-routing.module';
import { HomeModule } from './home/home.module';
import { AccountModule } from './account/account.module';
import { EntityModule } from './entities/entity.module';
import * as moment from 'moment';
// jhipster-needle-angular-add-module-import JHipster will add new module here
import { JhiMainComponent, NavbarComponent, FooterComponent, PageRibbonComponent, ActiveMenuDirective, ErrorComponent } from './layouts';
@NgModule({
imports: [
BrowserModule,
Ng2Webstorage.forRoot({ prefix: 'jhi', separator: '-' }),
NgJhipsterModule.forRoot({
// set below to true to make alerts look like toast
alertAsToast: false,
alertTimeout: 5000,
i18nEnabled: true,
defaultI18nLang: 'en'
}),
SharedModule.forRoot(),
CoreModule,
HomeModule,
AccountModule,
// jhipster-needle-angular-add-module JHipster will add new module here
EntityModule,
AppRoutingModule
],
declarations: [JhiMainComponent, NavbarComponent, ErrorComponent, PageRibbonComponent, ActiveMenuDirective, FooterComponent],
providers: [
{
provide: HTTP_INTERCEPTORS,
useClass: AuthInterceptor,
multi: true
},
{
provide: HTTP_INTERCEPTORS,
useClass: AuthExpiredInterceptor,
multi: true
},
{
provide: HTTP_INTERCEPTORS,
useClass: ErrorHandlerInterceptor,
multi: true
},
{
provide: HTTP_INTERCEPTORS,
useClass: NotificationInterceptor,
multi: true
}
],
bootstrap: [JhiMainComponent]
})
export class AppModule {
constructor(private dpConfig: NgbDatepickerConfig) {
this.dpConfig.minDate = { year: moment().year() - 100, month: 1, day: 1 };
}
}
这是 core.module 。
import { NgModule, LOCALE_ID } from '@angular/core';
import { DatePipe, registerLocaleData } from '@angular/common';
import { HttpClientModule } from '@angular/common/http';
import { Title } from '@angular/platform-browser';
import locale from '@angular/common/locales/en';
@NgModule({
imports: [HttpClientModule],
exports: [],
declarations: [],
providers: [
Title,
{
provide: LOCALE_ID,
useValue: 'en'
},
DatePipe
]
})
export class CoreModule {
constructor() {
registerLocaleData(locale);
}
}
提前感谢您的帮助。
【问题讨论】：
-
你能分享你的模块定义吗？
-
你能否确保你的两个服务都在你的 app.module.ts 文件的 providers 数组中
-
@O.MeeKoh 不，他们不是因为@Injectable({ providedIn: 'root' })
-
我不是 100% 确定，但是在使用 providedIn:root 属性时，为了将服务注入另一个服务，您可能会遗漏一些东西。尝试简单地从您的 AccountService 服务中删除 @Injectable() ，然后将其指定到 app.module.ts 提供程序数组中。看看这是否有效
-
@O.MeeKoh 感谢您的帮助。当我将它添加到 app.module 中时它可以工作，但我不知道为什么它不使用 @Injectable({ providedIn: 'root' }) 即使两个主题都做同样的工作。
标签： angular typescript ecmascript-6 dependency-injection jhipster