如何创建结合多个模板的 Angular 指令？答案

【问题标题】：How to create an Angular directive that combines multiple templates?如何创建结合多个模板的 Angular 指令？
【发布时间】：2022-11-17 13:53:52
【问题描述】：

我正在尝试创建一个自定义指令，该指令允许我从 json / ts 对象读取模板并将其插入我的指令模板中。

例如，在配置文件/数据库/ts 文件中，我有：

{
//...
  text: '<p>Many of our tools ...AD Groups:</p><AD_GROUPS id="AD_GROUPS"></AD_GROUPS><p>To request access, ...',
  AD_GROUPS: [
    'my-team-users'
  ],
//...
} // truncated and wrapped for readability

我想从配置文件中获取文本（html），用程序员传入的模板替换 <AD_GROUPS> 标签，并将其呈现到页面。该指令是这样使用的：

<div *appAdGroupText="cfg">
  <mat-list>
    <mat-list-item *ngFor="let group of cfg.AD_GROUPS">{{group}}</mat-list-item>
  </mat-list>
</div>

我创建了指令：

@Directive({selector: '[appAdGroupText]'})
export class AdGroupTextDirective implements OnChanges {

  _config: ConfigurationItemModel | undefined;

  constructor(
    private templateRef: TemplateRef<unknown>,
    private vcr: ViewContainerRef,
    private renderer: Renderer2
    // private resolver: ComponentFactoryResolver
  ) {
  }

  @Input() set appAdGroupText(cfg: ConfigurationItemModel) {
    this._config = cfg;
    this.render();
  }

  render() {
    const cfg = this._config; // config is set in a set method. This has the correct value
    const groupListDivElement: HTMLDivElement = this.renderer.createElement('my-group-text'); // creates a 'parent' element
    groupListDivElement.innerHTML = cfg.text; // set the inner html to the config text
    const adListDivRef = this.templateRef.createEmbeddedView(null); // create an unattached version of the template

    // loop through, and replace the "AD_GROUPS" custom tag with the generated template
    groupListDivElement.childNodes.forEach(n => {
    if (n.nodeName === 'AD_GROUPS') {
      n.replaceWith(adListDivRef.rootNodes[0]); // this is incorrect. I only get the root node, rather than the entire node with its children
    }
    // arguably, the above could be replaced with an Array.from(...) find / replace
    console.log(groupListDivElement); // SEE HTML OUTPUT
    // How do I render groupListDivElement in the VCR / renderer???


      // this works will put the mat-list ONLYin:
      // let view = this.templateRef.createEmbeddedView(null);
      // this.vcr.insert(view);
  }
}

从 console.log 生成的 HTML：

<my-group-text _ngcontent-hwh-c107="">
<p>Many of our tools are restricted to specific groups in Active Directory. In order to access the required tools, you will need access to the following AD Groups:</p>
<div _ngcontent-hwh-c107="">
   <mat-list _ngcontent-hwh-c107="" class="mat-list mat-list-base">
      <!--container-->
   </mat-list>
</div>
<p>
   To request access, <a href="https://access" target="_blank" rel="noopener noreferrer">click here</a> and fill out the form with the following information:
   <ad_form_table></ad_form_table>
</p>
<p>You will need to create a ticket for each of the above groups listed.</p>
</ad-group-text>

问题

如何将 adListDivRef 附加到正确的父级？我想我可以这样访问父母：this.renderer.parentNode(this.vcr.element.nativeElement)？
mat-list 似乎没有从我嵌入的*ngFor 中找到列表项。我怎么得到它？我在想也许我的指令首先被调用而下一个没有被调用？
代码最少的 Stackblitz： https://stackblitz.com/edit/angular-ivy-zv16cn

【问题讨论】：

标签： javascript html angular angular-renderer2

【解决方案1】：

这里有两个步骤来实现你的目标：

将生成的ag-group-text元素放入页面

this.vcr.element.nativeElement.parentNode.appendChild(groupListDivElement);

将正确的 context 传递到动态生成的模板中

const adListDivRef: EmbeddedViewRef<any> = 
    this.vcr.createEmbeddedView(this.templateRef, { cfg });

Forked Stackblitz

【讨论】：