Angular使用@Input和@Output实现父子组件互相传参（类似Vue的props和this.emit）

<app-in-out [in]='"传输进入"' (out)="out($event)" ></app-in-out>

import { Component } from '@angular/core';
@Component({
  selector: 'app-root',
  templateUrl: './app.component.html'
})
export class AppComponent {
  out($event: any) {
    alert($event);
  }
}

<h1>来自父组件的参数：{{in}}</h1> 
<button (click)="out.emit('向父组件传参')">向父组件传参</button>

import { Component, Input, OnInit, Output, EventEmitter } from '@angular/core';
 
@Component({
  selector: 'app-in-out',
  templateUrl: './in-out.component.html',
  styleUrls: ['./in-out.component.css']
})
export class InOutComponent implements OnInit {
 
  constructor() { }
 
  @Input() in: any = '';//从父组件传入参数进来
  @Output() out = new EventEmitter;//从子组件传出参数到父组件（采用事件的方式，类似Vue的emit）
  
  ngOnInit(): void {  }
 
}