<ul class="left">
  <li *ngFor="let categoryItem of categoryList" 
  (click)="switchCategory(categoryItem.dropOptionOrder)"
  [ngClass]="{'actived':selectedCategoryId===categoryItem.dropOptionOrder}">
  {{categoryItem.dropOptionName}}
  </li>
</ul>
<div class="materialContainer">
  <div class="materialItem" *ngFor="let posterInfo of posterInfos;index as i"
       [routerLink]="['/material',posterInfo.itemId]" [queryParams]="{itemType:posterInfo.itemType}">
    <div>
      <img src="{{posterInfo.thumbnailPath}}" alt="" class="img-responsive">
    </div>
    <div class="title">{{posterInfo.title}}</div>
  </div>
</div>
