angular8的双向绑定

ngModel

FormsModule 中提供的指令

使用[(ngModel)] = "变量"   形式进行双向绑定

[(ngModel)] = "username"  (ngModelChange) = "username = $event"

 

在app.module.ts中使用

import {FormsModule} from '@angular/forms'

imports: [

[BrowserModule,FormsModule]

],

子组件  双向绑定是怎么来的

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

@Component({
  selector: 'app-horizontal-grid',
  templateUrl: './horizontal-grid.component.html',
  styleUrls: ['./horizontal-grid.component.css']
})
export class HorizontalGridComponent implements OnInit {
  private _username =  '';
  constructor() { }
  @Output() usernameChange = new EventEmitter();
  @Input()
  public get username() : string {
    return this._username;
  }
  
  public set username(value : string) {
    this._username = value;
     this.usernameChange.emit(value)
  }
  
  
  ngOnInit() {
  }

}

父组件

语法糖