使用指令使用渲染器添加属性 [英] Add attribute with renderer using a directive

问题描述

我想实现扩展带有属性的HTML标记，但将其封装在angular 2组件中.

I want to achieve extending an HTML tag with an attribute but encapsulate this with an angular 2 component.

让我们使用Angular 2组件foo来假定原始标记

Let's assume the original markup using my Angular 2 component foo

<div foo="x"></div>

foo属性应将div转换为:

The foo attribute should transform the div like:

<div some-other-fancy-attribute="x"></div>

首先，我尝试实现一个指令，但无法弄清楚如何使用angular/core中的Renderer向宿主元素添加另一个属性.

First I tried implementing a directive but I could not figure out how to add another attribute to the hosting element using Renderer from angular/core.

然后，我使用[foo]这样的属性选择器了解了Angular 2组件.我喜欢使用模板来呈现其他一些花式属性的想法.

Then I read about Angular 2 components using an attribute selector like [foo]. I liked the idea of using a template to render some-other-fancy-attribute.

但是，模板是在标记后呈现的，所以我最终得到了:

However, the template get's rendered AFTER the tag so I end up with:

<div foo="x">some-other-fancy-attribute="x"

没有简单的方法来封装某些属性创建吗? 认为这是一件微不足道的事，但它给我带来的头痛比预期的要多.

Isn't there an easy way to encapsulate some attribute creation? Thought this is a trivial one but it gives me more headache than expected.

推荐答案

如果我理解的正确. 您的想法很好，应该可以！

If I understood you right.. your idea is good, should work!

请参阅以下示例: https://plnkr.co/edit/YctUpK9r9AqIk0D1qvgZ?p=preview

已更新为使用Renderer2

import {Component, Directive, NgModule, ElementRef, Renderer2, ViewChild} from '@angular/core'
import {BrowserModule} from '@angular/platform-browser'

@Directive({
  selector: '[foo]'
})
export class MyFancyDirective {

  constructor (private _elRef: ElementRef, private _renderer: Renderer2) { console.log('!'); }

  ngOnInit() {
    this._renderer.setAttribute(this._elRef.nativeElement, 'another-fancy-attribute', 'HERE I AM !!');
  }

}

@Component({
  selector: 'my-app',
  template: `
    <div>
      <h2 #header foo (click)="headerClicked()">Hello {{name}}</h2>
    </div>
  `,
})
export class App {

  @ViewChild('header', { static: true }) header: ElementRef;

  name:string;
  constructor() {
    this.name = 'Angular2'
  }

  headerClicked() {
    console.dir(this.header.nativeElement.attributes['another-fancy-attribute'].value);
  }
}

@NgModule({
  imports: [ BrowserModule ],
  declarations: [ App, MyFancyDirective ],
  bootstrap: [ App ]
})
export class AppModule {}

这篇关于使用指令使用渲染器添加属性的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！