如何在Mat-Toolbar中选中被点击的链接

<mat-toolbar>
  <a mat-button (click)="selectLink('link1')">Link 1</a>
  <a mat-button (click)="selectLink('link2')">Link 2</a>
  <a mat-button (click)="selectLink('link3')">Link 3</a>
</mat-toolbar>

selectedLink: string;

selectLink(link: string) {
  this.selectedLink = link;
}

<mat-toolbar>
  <a mat-button [class.active]="selectedLink === 'link1'" (click)="selectLink('link1')">Link 1</a>
  <a mat-button [class.active]="selectedLink === 'link2'" (click)="selectLink('link2')">Link 2</a>
  <a mat-button [class.active]="selectedLink === 'link3'" (click)="selectLink('link3')">Link 3</a>
</mat-toolbar>

.active {
  background-color: #e0e0e0;
  color: #000000;
}