如何在ng2-select中实现“全选”和“全选”功能

<ng-select [items]="options" [multiple]="true" [(ngModel)]="selectedOptions">
  <ng-option *ngFor="let option of options" [value]="option">{{option}}</ng-option>
</ng-select>

<input type="checkbox" [(ngModel)]="selectAll" (change)="toggleSelectAll()">

import { Component } from '@angular/core';

@Component({
  selector: 'app-select',
  templateUrl: './select.component.html',
  styleUrls: ['./select.component.css']
})
export class SelectComponent {
  options: string[] = ['Option 1', 'Option 2', 'Option 3', 'Option 4'];
  selectedOptions: string[] = [];
  selectAll: boolean = false;

  toggleSelectAll() {
    if (this.selectAll) {
      this.selectedOptions = [...this.options];
    } else {
      this.selectedOptions = [];
    }
  }
}