子组件视图

<button (click)="sengMsg()">发送消息给父组件</button>

子组件：导入事件发射器：EventEmitter，导入Output

import { Component, OnInit, Input, Output,EventEmitter } from '@angular/core';

@Component({
  selector: 'app-child',
  templateUrl: './child.component.html',
  styleUrls: ['./child.component.scss']
})
export class ChildComponent implements OnInit {
  @Input() item: any;
  @Output() childMsg=new EventEmitter();
  constructor() { }
  sengMsg(){
    this.childMsg.emit({msg:"我是子组件，这是我发给父组件的消息"})
  }

  ngOnInit(): void {
  }

}

父组件视图

<h1>子组件发来信息{{getChildMsg}}</h1>
<app-child [item]="sendchildMsg" (childMsg)="getEvent($event)"></app-child>

父组件

export class AppComponent {
  msg="";
  title = 'my-App';
  sendchildMsg = '这是给子元素的数据，希望在子组件中显示';
  getChildMsg = "";
  getEvent(event:any){
    console.log(event);
    this.getChildMsg=event.msg;
  }
}