如果复选框处于选中状态，如何向matInput添加所需的验证

<mat-checkbox [(ngModel)]="isChecked">选中</mat-checkbox>

<mat-form-field>
  <input matInput [(ngModel)]="inputValue" [required]="isChecked">
</mat-form-field>

import { Component } from '@angular/core';
import { FormControl, Validators } from '@angular/forms';

@Component({
  selector: 'app-example',
  templateUrl: './example.component.html',
  styleUrls: ['./example.component.scss']
})
export class ExampleComponent {
  isChecked: boolean = false;
  inputValue: string;

  get inputValidator(): Validators | null {
    return this.isChecked ? Validators.required : null;
  }
}

<mat-form-field>
  <input matInput [(ngModel)]="inputValue" [required]="isChecked" [validators]="inputValidator">
</mat-form-field>