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angularjs - 如何在 ng-if 条件中使用枚举?(angular2/typescript)


我有一个视图,在这个视图中有三个按钮:

showListOne()

showListTwo()

showListThree()

当点击这些按钮中的每一个时,我想在同一个视图中展示不同的列表,但不是同时展示(一次只展示一个列表,就像标签页的行为)。

所以我想用枚举来做,就是这样:

导出枚举 当前列表视图 { 人员, 汽车, 地点 }

@Component({
  selector: 'my-app',
  styles: [require('./my-app.css')],
  directives: [DND_DIRECTIVES],
  providers: [DND_PROVIDERS],
  template: require('./my-app.component.html')
})

  @Injectable()
  export class AppCmp implements OnInit {

    listOfPeople: Person[];
    listOfCars: Car[];
    listOfPlaces: Place[];

    currentListView: CurrentListView;

    constructor(private _MyService: MyService) {
    };

    public showListOfPeopleData(): void {
      this.currentListView = CurrentListView.People;
    }

    public showListOfCarsData(): void {
      this.currentListView = CurrentListView.Cars;
    }

    public showListOfPlacesData(): void {
      this.currentListView = CurrentListView.Places;
    }

    ngOnInit() {
      this._MyService.getListOfPeopleData().subscribe(res => {
        this.listOfPeople = res;
      });

      this._MyService.getListOfCarsData().subscribe(res => {
        this.listOfCars = res;
      });

      this._MyService.getListOfPlacesData().subscribe(res => {
        this.listOfPlaces = res;
      });
    }
  }

现在,我如何使用 ng-if 来询问 currentListView 的状态?这是我的视图(里面的 ng-if 是我尝试过的,但它不起作用):

<div *ngIf="currentListView == CurrentListView.People">
    <div dnd-sortable-container [dropZones]="['zone-one']" [sortableData]="listOfPeople">
      <div class="list-bg" *ngFor="#person of listOfPeople; #i = index" dnd-sortable [sortableIndex]="i">
        ID: {{person.id}} <p></p> Age: {{person.age}}
      </div>
    </div>
  </div>

<div *ngIf="currentListView == CurrentListView.Cars">
    <div dnd-sortable-container [dropZones]="['zone-one']" [sortableData]="listOfCars">
      <div class="list-bg" *ngFor="#car of listOfCars; #i = index" dnd-sortable [sortableIndex]="i">
        ID: {{car.id}} <p></p> Color: {{car.color}}
      </div>
    </div>
  </div>

<div *ngIf="currentListView == CurrentListView.Places">
    <div dnd-sortable-container [dropZones]="['zone-one']" [sortableData]="listOfPlaces">
      <div class="list-bg" *ngFor="#place of listOfPlaces; #i = index" dnd-sortable [sortableIndex]="i">
        City: {{place.city}} <p></p> Capacity: {{place.capacity}}
      </div>
    </div>
  </div>

我的 TypeScript 或 HTML 能否更高效?我很想看到一个更通用的方法来实现这一点,而不需要重复。

非常感谢!

答案#1

我认为你不能比较数组(更不用说性能很差了),我建议你可以将“要显示的列表”存储在某个字符串变量中,类似这样:

    currentListView:string = 'Bikes';

就像在这个 plunkr 中一样