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This time I will show you how to avoid the misunderstandings of using Dom in Angular. What are the precautions for using Dom in Angular? The following is a practical case, let's take a look.
Preface
The design goal of Angular2 is to make the browser and DOM independent. The DOM is complex, so decoupling components from it will make our applications easier to test and refactor. In order to support cross-platform, Angular also encapsulates the differences of different platforms through abstraction.Content
#1. Why can’t the DOM be manipulated directly?
Angular2 adopts AOT static compilation mode. In this form, our template type must be stable and safe. Directly2. Three incorrect ways to operate DOM:
@Component({ ... }) export class HeroComponent { constructor(private _elementRef: ElementRef) {} doBadThings() { $('id').click(); //jquery this._elementRef.nativeElement.xyz = ''; //原生的ElementRef document.getElementById('id'); //javascript } }
3. How does Angular2 DOM operate mechanism?
In order to support cross-platform, Angular encapsulates the differences of different platforms through abstraction layers. For example,4. Correct way to operate DOM (ElementRef and Renderer2):
product.component.html<p>商品信息</p> <ul> <li *ngFor="let product of dataSource| async as list"> {{product.title}} </li> </ul> <p #dia> </p>product.component.ts
import { Component, OnInit,Renderer2, ViewChild,ElementRef,AfterViewInit} from '@angular/core'; @Component({ selector: 'app-product', templateUrl: './product.component.html', styleUrls: ['./product.component.css'] }) export class ProductComponent implements OnInit,AfterViewInit { @ViewChild('dia') dia:ElementRef ;定义子试图 ngOnInit() { /**1. *创建一个文本 */ this.dia.nativeElement.innerHTML="这只是一个测试的文档"; /**2. *添加click事件 */ let ul=this.element.nativeElement.querySelector('ul'); this.render2.listen(ul,"click",()=>{ this.render2.setStyle(ul,"background","blue"); ngAfterViewInit(){ /**3. *修改背景颜色 */ let li=this.element.nativeElement.querySelector('ul'); this.render2.setStyle(li,"background","red"); } }I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the php Chinese website! Recommended reading:
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