选择下拉列表在提交表单时发送null (Angular，Reactive Form)

<form [formGroup]="myForm" (ngSubmit)="onSubmit()">
  <select formControlName="selectedOption">
    <option value="" disabled>请选择</option>
    <option *ngFor="let option of options" [value]="option.value">{{ option.label }}</option>
  </select>
  <button type="submit">提交</button>
</form>

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

@Component({
  selector: 'app-my-form',
  templateUrl: './my-form.component.html',
  styleUrls: ['./my-form.component.css']
})
export class MyFormComponent {
  myForm: FormGroup;
  options = [
    { value: 'option1', label: '选项1' },
    { value: 'option2', label: '选项2' },
    { value: 'option3', label: '选项3' }
  ];

  constructor(private fb: FormBuilder) {
    this.myForm = this.fb.group({
      selectedOption: ['', Validators.required]
    });
  }

  onSubmit() {
    console.log(this.myForm.value);
  }
}