0

我参考了以下链接，仅在登录 https://stackblitz.com/edit/angular-login-hide-navbar-ngif后启用注销按钮

我只想在用户登录时在导航栏中显示“注销”，我正在通过从“身份验证服务”调用“this.authservice.isUserLoggedIn”并将其分配给变量并写入来验证用户是否已登录ngif“注销”链接附近的情况。我已经使用 BehaviourSubject 来获取当前状态。但我不知道为什么代码不起作用，它总是返回 false，因此即使在用户登录后也没有启用“注销”链接

我有 header.component.ts

export class CommonheaderComponent implements OnInit {

  constructor(private authservice : AuthenticationService) { }
  isLoggedIn$ : Observable<boolean>;
  ngOnInit() {
    this.isLoggedIn$ = this.authservice.isUserLoggedIn;
  }
  }

我有如下 header.component.html

<ul class="nav navbar-nav">
      <li><a [routerLink]='["/search"]'>Search <span class="slider"></span></a></li>
      <li *ngIf="isLoggedIn"><a (click)="logout()">Logout</a></li>
  </ul>

下面是 login.component.ts

export class LoginComponent implements OnInit {
  isLoggedIn : Observable<boolean>;

 ngOnInit() {
   this.isLoggedIn = this.authservice.isUserLoggedIn;
   this.loginForm = this.formbuilder.group({
    username : ['', Validators.required],
    password : ['', Validators.required]
  })
 }

}

  onSubmit(){
    this.authservice.login(this.loginForm.value).subscribe(data => {
  })    
 }
}

我有如下认证服务

    import { Injectable } from '@angular/core';
    import { HttpClient, HttpHeaders } from '@angular/common/http';
    import { BehaviorSubject, Observable } from 'rxjs';
    import { map } from 'rxjs/operators';
    import { User } from '../_models/user';
    import { Router } from '@angular/router';

    const httpOptions =  {
      headers : new HttpHeaders({'Content-type' : 'application/json'})
    }

    @Injectable({
      providedIn: 'root'
    })
    export class AuthenticationService {
      private currentUserSubject : BehaviorSubject<User>;
      private currentUser : Observable<User>;
      private loggedIn: BehaviorSubject<boolean> = new BehaviorSubject<boolean>(false);

      constructor(private http: HttpClient, private router: Router) {
        this.currentUserSubject = new BehaviorSubject<User>(JSON.parse(localStorage.getItem('currentUser')));
        this.currentUser = this.currentUserSubject.asObservable();
      }

      public get currentUserValue(): User{
        return this.currentUserSubject.value;
      }

      public login(user: User):Observable<any>{
        var baseUrl = "http://localhost:3000/";
        return this.http.post<any>(baseUrl+'auth/login', user, httpOptions).pipe(map(user => {
          if(user && user.accesstoken){
            localStorage.setItem('currentUser', JSON.stringify(user));
            this.currentUserSubject.next(user);
            this.loggedIn.next(true);
          }else{
            return false;
          }
          return user;
        }))
      }

      get isUserLoggedIn(){
          return this.loggedIn.asObservable();
      } 
    }

我在哪里做错了。或者对此的解决方案/替代方案是什么。请帮忙！！

很长一段时间以来我一直坚持这一点

4

2 回答 2

3

您可以像这样更改模板后尝试：

<ul class="nav navbar-nav">
      <li><a [routerLink]='["/search"]'>Search <span class="slider"></span></a></li>
      <li *ngIf="isLoggedIn$ | async"><a (click)="logout()">Logout</a></li>
  </ul>

注意async管道解开可观察值。

请注意，在您共享的 stackblitz 示例中 - 可观察值已使用async管道展开 -

<mat-toolbar color="primary" *ngIf="isLoggedIn$ | async as isLoggedIn">
于 2019-07-07T17:58:30.193 回答
1

对于您的最后一条评论，发生这种情况是因为正在重新初始化服务并且正在重置您的 observable。将此添加到您的构造函数

if(localStorage.getItem('currentUser') != null)
    this.loggedIn.next(true);

这对我有用。

于 2019-09-26T15:11:23.623 回答