如何在angular中做dropdown而没有警告或者ngModel？

import { FormsModule, ReactiveFormsModule } from '@angular/forms';

import { FormGroup, FormControl } from '@angular/forms';

@Component({
  // 组件配置
})
export class YourComponent {
  form: FormGroup;

  constructor() {
    this.form = new FormGroup({
      dropdown: new FormControl('') // 这里的''是下拉菜单的初始值
    });
  }
}

<form [formGroup]="form">
  <select formControlName="dropdown">
    <option value="option1">选项1</option>
    <option value="option2">选项2</option>
    <option value="option3">选项3</option>
  </select>
</form>

// 获取下拉菜单的值
const dropdownValue = this.form.get('dropdown').value;

// 检查下拉菜单的有效性
const isDropdownValid = this.form.get('dropdown').valid;