汪汪一只猫
import { Component, OnInit, Output, Input, EventEmitter } from '@angular/core';@Component({selector: 'twoway',template: `<input [(ngModel)]="username"><p>Hello {{username}}!</p>`})export class TwoWayComponent implements OnInit {constructor() { }usernameValue: string;@Output() usernameChange = new EventEmitter();@Input()get username() {return this.usernameValue;}set username(val) {this.usernameValue = val;this.usernameChange.emit(this.usernameValue);}ngOnInit() {}}使用时，就可以通过[(username)]=“你的当前属性” 进行双向绑定了。属性名 + 后缀 Change是一个约定的固定写法。