如何从服务中调用组件(Modal Popup)？

import { Injectable } from '@angular/core';
import { ModalComponent } from './modal.component'; // 引入组件所在的模块

@Injectable()
export class ModalService {
  private modal: ModalComponent; // 组件实例

  constructor() { }

  setModal(modal: ModalComponent) {
    this.modal = modal;
  }

  openModal(content: string) {
    // 在组件中显示不同的内容
    this.modal.setContent(content);
    this.modal.show(); // 调用组件的显示方法
  }

  closeModal() {
    this.modal.hide(); // 调用组件的关闭方法
  }
}

import { Component, OnInit } from '@angular/core';
import { ModalService } from './modal.service';

@Component({
  selector: 'app-example',
  template: `
    <button (click)="openModal()">打开模态框</button>
    <app-modal></app-modal>
  `,
})
export class ExampleComponent implements OnInit {
  constructor(private modalService: ModalService) { }

  ngOnInit() {
    this.modalService.setModal(this.modal); // 设置组件实例
  }

  openModal() {
    this.modalService.openModal('这是模态框的内容'); // 调用服务中的方法来显示组件
  }
}