父母和孩子通过angular 8中的服务进行通信

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

@Injectable({
  providedIn: 'root'
})
export class DataService {
  private data: string;

  setData(data: string) {
    this.data = data;
  }

  getData() {
    return this.data;
  }
}

import { Component } from '@angular/core';
import { DataService } from './data.service';

@Component({
  selector: 'app-parent',
  template: `
    <h2>Parent Component</h2>
    <input [(ngModel)]="data" (ngModelChange)="updateData()" placeholder="Enter data">
    <app-child></app-child>
  `,
  providers: [DataService]
})
export class ParentComponent {
  data: string;

  constructor(private dataService: DataService) {}

  updateData() {
    this.dataService.setData(this.data);
  }
}

import { Component } from '@angular/core';
import { DataService } from './data.service';

@Component({
  selector: 'app-child',
  template: `
    <h2>Child Component</h2>
    <p>Data from parent: {{ data }}</p>
  `,
  providers: [DataService]
})
export class ChildComponent {
  data: string;

  constructor(private dataService: DataService) {}

  ngOnInit() {
    this.data = this.dataService.getData();
  }
}