角度-如何自动触发mat-error

<form [formGroup]="myForm">
  <mat-form-field>
    <input matInput formControlName="myControl" required>
    <mat-error *ngIf="myForm.get('myControl').invalid && myForm.get('myControl').touched">
      错误消息内容
    </mat-error>
  </mat-form-field>
</form>

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

@Component({
  selector: 'app-my-component',
  templateUrl: './my-component.component.html',
  styleUrls: ['./my-component.component.css']
})
export class MyComponentComponent implements OnInit {
  myForm: FormGroup;

  constructor(private formBuilder: FormBuilder) { }

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