Angular 5下拉菜单

Question

Angular 5我无法通过下拉菜单显示"类别",类别存在于item.category和类别中,并且是相同的.我尝试过使用ngModel和ngValue而只是值,并且不能让它工作

<td>
   <select [(ngModel)]="item.category">
        <option style="display:none">select a category</option>
        <option *ngFor="let item of categories" [ngValue]="item.category" value="item.category">{{item.category}}</option>
      </select>
    </td>

Answer 1

对我来说,这样工作:

<select [(ngModel)]="category" id="category">
   <option value="" disabled selected>select a category</option>
   <option *ngFor="let item of categories" [value]="item.category">{{item.category}}</option>
 </select>