Angular 是否在HTML视图中显示sesstionStorage字符串？

我只想在角度视图中显示存储在会话存储中的数据

我的遗产存储：

sessionStorage.getItem('username');

My dashboard.ts文件：

export class DashboardComponent implements OnInit {
  currentUserSubscription: Subscription;

  constructor(private authenticationService: AuthenticationService){

  }

  ngOnInit() {

  }
}

export class DashboardComponent implements OnInit {
  username: string;

  constructor(private authenticationService: AuthenticationService){}

  ngOnInit() {
   this.username = this.authenticationService.getUsername();
  }
}

我的HTML文件：

<div *ngIf = "username">
          <p class="introText"><b>Welkom:</b> {{ username }}
            <button mat-button (click)="clockIn()" class="mat-raised-button mat-primary clockButton">
              Inklokken
            </button>
            <button mat-button type="submit" class="mat-raised-button mat-basic">
              Uitklokken
            </button> <br> 
            <b>Ingelogd: </b>{{dateTime}}
      </div>

Welkom:{{username}
因克洛肯
尤特克洛肯


Ingelogd:{{dateTime}

及

Welkom:{{username} dashboard.ts文件：

export class DashboardComponent implements OnInit {
  currentUserSubscription: Subscription;

  constructor(private authenticationService: AuthenticationService){

  }

  ngOnInit() {

  }
}

export class DashboardComponent implements OnInit {
  username: string;

  constructor(private authenticationService: AuthenticationService){}

  ngOnInit() {
   this.username = this.authenticationService.getUsername();
  }
}

authentication.service.ts

@Injectable({
  providedIn: 'root'
})
export class AuthenticationService{
   getUsername():string {
      return sessionStorage.getItem('username');
   }
}

---

我不确定我是否理解为什么这需要成为一个问题。您已经知道如何从会话存储中获取值，那么为什么在获取值时不能存储该值呢？