A brief discussion on DOM operations in Angular

This article will introduce to you the DOM operations in Angular. It has certain reference value. Friends in need can refer to it. I hope it will be helpful to everyone.

Related recommendations: "angular Tutorial"

1. Dom operations in Angular and @ViewChild, Angular execution css3 animation

1.1 Native js dom operation and animation

Demo component: app\components\transition
HTML

<div class="content">

    <p>内容区域</p>

    <div id="box">
          this is box
    </div>
    <br>
    <div id="box1" *ngIf="flag">
      this is box1  
    </div>

    <button (click)="showAside()">弹出侧边栏</button>
    <button (click)="hideAside()">隐藏侧边栏</button>
  </div>
  
  <aside id="aside">
    这是一个侧边栏
  </aside>

Component ts:

public flag:boolean=true;
  constructor() { }

  ngOnInit(): void {
      //组件和指令初始化完成   并不是真正的dom加载完成
      let oBox:any=document.getElementById('box');
      console.log(oBox.innerHTML);
      oBox.style.color="red";
      //获取不到dom节点
     /*
      let oBox1:any=document.getElementById('box1');
      console.log(oBox1.innerHTML);
      oBox1.style.color="blue";
     
     */
  }
     //视图加载完成以后触发的方法    dom加载完成  （建议把dom操作放在这个里面）  
    ngAfterViewInit(){
        let oBox1:any=document.getElementById('box1');
        console.log(oBox1.innerHTML);
        oBox1.style.color="blue";
    }

  showAside(){
    //原生js获取dom节点
    var asideDom:any=document.getElementById('aside');
    asideDom.style.transform="translate(0,0)";

 }

hideAside(){
   //原生js获取dom节点
   var asideDom:any=document.getElementById('aside');
   asideDom.style.transform="translate(100%,0)";

}

1.2 DOM operation in Angular (ViewChild)

ViewChild: Property decorator

Demo file:\ngDemo\src\ app\components\news

1. Now the component template file defines attributes through

#

<div #myBox>
   我是一个dom节点
</div>

2. Now the component ts gets dom

<div #myBox>我是一个dom节点</div>
<app-header #header></app-header>
<button type="button" (click)=&#39;getChildProp()&#39;>获取子组件header的属性</button>
<button type="button" (click)=&#39;getChildMethod()&#39;>获取子组件header的方法</button>

import { Component, OnInit, ViewChild } from '@angular/core';

@Component({
  selector: 'app-news',
  templateUrl: './news.component.html',
  styleUrls: ['./news.component.less']
})
export class NewsComponent implements OnInit {
  //获取Dom
  @ViewChild('myBox')
  public myBoxIn: any;

  @ViewChild('header')
  public header: any;

  constructor() { }

  ngOnInit(): void {
    // console.log(this.myBoxIn)

  }

  //处理dom节点
  ngAfterViewInit() {
    console.log(this.myBoxIn.nativeElement)

    //父组件获取到了整个子组件header
    console.log('父组件获取到了整个子组件header')
    console.log(this.header)
  }
  //获取子组件header的属性
  getChildProp() {
    console.log(this.header.title)

  }
  //获取子组件header的方法
  getChildMethod() {
    console.log(this.header.headRun)
    this.header.headRun();
  }

}


// 父组件   news   引入 <app-header #header></app-header>
// 子组件  header

// 父组件 得到 子组件的 数据 和 方法   ---   子组件 传 值给父组件  


// 总结：
// 1. 父组件中调用子组件的时候， 给子组件一个名称
// <app-header #header></app-header>
// 2. 在父组件引入viewChild

// import { Component, OnInit,ViewChild } from &#39;@angular/core&#39;;


// @ViewChild(&#39;header&#39;)
// public header:any;

// 3. 已经可以在父组件调用子组件的属性和方法了


// 父组件传值给子组件  @input   -- 子组件 得到 父组件的 数据 和 方法 

// 父组件： home
// 子组件： header

more through ViewChild For programming-related knowledge, please visit: Introduction to Programming! !

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