折叠表格行中的角材料

Question

我如何在角形材料设计中折叠展开的行

<tr mat-header-row *matHeaderRowDef="displayedColumns"></tr>
      <tr mat-row *matRowDef="let element; columns: displayedColumns;"
          class="example-element-row"
          [class.example-expanded-row]="expandedElement === element"
          (click)="publisherspiltup(element)">
      </tr>
      <tr mat-row *matRowDef="let row; columns: ['expandedDetail']" class="example-detail-row"></tr>