1. 确保在路由定义中正确配置了AuthGuard。

例如，在app-routing.module.ts中定义路由：

const routes: Routes = [
  { path: 'dashboard', component: DashboardComponent, canActivate: [AuthGuard] },
  ...
];

2. 确保AuthGuard中的canActivate()方法返回一个Observable或Promise。

例如，在auth.guard.ts中定义AuthGuard：

@Injectable({
  providedIn: 'root'
})
export class AuthGuard implements CanActivate {
  constructor(private authService: AuthService, private router: Router) {}

  canActivate(route: ActivatedRouteSnapshot, state: RouterStateSnapshot): Observable | Promise | boolean {
    return this.authService.isLoggedIn()
      .pipe(
        map((isLoggedIn: boolean) => {
          if (!isLoggedIn) {
            this.router.navigate(['/login']);
            return false;
          }
          return true;
        })
      );
  }
}

3. 确保AuthService中的isLoggedIn()方法返回一个Observable或Promise。

例如，在auth.service.ts中定义AuthService：

@Injectable({
  providedIn: 'root'
})
export class AuthService {
  // use BehaviorSubject to keep track of login state
  private loggedIn = new BehaviorSubject(false);

  constructor() { }

  isLoggedIn(): Observable {
    // return BehaviorSubject as an Observable
    return this.loggedIn.asObservable();
  }

  login() {
    this.loggedIn.next(true);
  }

  logout() {
    this.loggedIn.next(false);
  }
}

在login.component.ts中处理用户登录：

export class LoginComponent implements OnInit {
  constructor(private authService: AuthService) {}

  ngOnInit() {}

  login() {
    // authenticate user and set isLoggedIn to true
    this.authService.login();
  }
}

在navbar.component.ts中处理用户注销：

export class NavbarComponent implements OnInit {
  constructor(private authService: AuthService) {}

  ngOnInit() {}

  logout() {
    // log out user and set isLoggedIn to false
    this.authService.logout();
  }
}