如何在angular material中显示为空的页面上的表格

import { MatTableDataSource } from '@angular/material/table';
import { MatSort } from '@angular/material/sort';

dataSource: MatTableDataSource<any>;
@ViewChild(MatSort, { static: true }) sort: MatSort;

ngOnInit() {
  this.dataSource = new MatTableDataSource<any>([]);
  this.dataSource.sort = this.sort;
}

<div *ngIf="dataSource.data.length === 0">表格为空</div>

<table mat-table [dataSource]="dataSource" matSort>
  <!-- 表格列定义 -->
  <ng-container matColumnDef="column1">
    <th mat-header-cell *matHeaderCellDef mat-sort-header>列1</th>
    <td mat-cell *matCellDef="let element">{{element.column1}}</td>
  </ng-container>

  <!-- 其他表格列定义 -->

  <!-- 表格行定义 -->
  <tr mat-header-row *matHeaderRowDef="displayedColumns"></tr>
  <tr mat-row *matRowDef="let row; columns: displayedColumns;"></tr>
</table>