Angular 4如何限制组件的创建

Question

示例代码

<p-accordion *ngIf="cat" (onOpen)="openTabAccordion($event)" [ngClass]="{'p-accordion':true}">
  <p-accordionTab *ngFor="let item of cat;let i = index"  [header]="item.data.name">
    <div *ngIf="results; else loading">
        <p-listbox  *ngIf="results.length > 0; else not_data" [style]="{'width':'100%','max-height':'250px'}"
            [options]="results"
            [(ngModel)]="currentP" (onChange)="selectedP($event);">
            <ng-template let-p pTemplate="item">
                <app-p-i [prop]="p.value"></app-p-i>
            </ng-template>
        </p-listbox>
        <ng-template #not_data>
            Not Record Found
        </ng-template>
    </div>
    <ng-template #loading>loading ...</ng-template>
  </p-accordionTab>
</p-accordion>

组件app-p-i我希望它只在当前的accordionTab中调用，但是当调试app-p-i时，它会创建很多实例，以便accordionTab具有p-accordion。

如何限制组件的创建只打开accordionTab，可以或者我已定义每个accordionTab显式