如何用反应式表单验证angular中的单选按钮字段

import { Component, OnInit } from '@angular/core';
import { FormBuilder, FormGroup, Validators } from '@angular/forms';

export class MyComponent implements OnInit {
  myForm: FormGroup;

  constructor(private formBuilder: FormBuilder) { }

  ngOnInit() {
    this.myForm = this.formBuilder.group({
      radioButton: ['', Validators.required]
    });
  }
}

<form [formGroup]="myForm">
  <label>
    <input type="radio" formControlName="radioButton" value="option1"> Option 1
  </label>
  <label>
    <input type="radio" formControlName="radioButton" value="option2"> Option 2
  </label>
  <label>
    <input type="radio" formControlName="radioButton" value="option3"> Option 3
  </label>
</form>

<div *ngIf="myForm.get('radioButton').invalid && myForm.get('radioButton').touched">
  <div *ngIf="myForm.get('radioButton').errors.required">Please select an option.</div>
</div>

export class MyComponent implements OnInit {
  // ...

  onSubmit() {
    if (this.myForm.valid) {
      // 表单验证通过，执行相应的操作
    } else {
      // 表单验证失败，显示错误消息
    }
  }
}