点击事件在 innerhtml 字符串 angular 6 中不起作用

Question

I am working on an generate dynamic template using angular 6. I have an API that return strings like below:

    <button type="button" (click)="openAlert()">click me</button>

and html

    <div [innerHtml]="myTemplate | safeHtml">
      </div>

function is bellow:

    openAlert() {
        alert('hello');
      }

Answer 1

You cannot bind angular events directly to innerHTML.

Still if you need to attach the event listeners you need to to do it after the html content is loaded.

Once the content is set to the variable, ngAfterViewInit Angular life cycle event will be triggered. Here you need to attach the required event listeners.

Checkout the working example below.

component.html

<button (click)="addTemplate()">Get Template</button>
<div [innerHTML]="myTemplate | safeHtml"></div>

component.ts

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

@Component({
  selector: 'my-app',
  templateUrl: './app.component.html',
  styleUrls: [ './app.component.css' ]
})
export class AppComponent  {
  name = 'Angular';
  myTemplate  = '';

  constructor(private elementRef:ElementRef){

  }
  openAlert() {
    alert('hello');
  }
  addTemplate(){
     this.myTemplate  = '<button type="button" id="my-button" (click)="openAlert()">click mee</buttn>';
  }
  ngAfterViewChecked (){
    if(this.elementRef.nativeElement.querySelector('#my-button')){
      this.elementRef.nativeElement.querySelector('#my-button').addEventListener('click', this.openAlert.bind(this));
    }
  } 
}

safe-html.pipe.ts

import { Pipe, PipeTransform } from '@angular/core';
import { DomSanitizer } from '@angular/platform-browser';
@Pipe({
  name: 'safeHtml'
})
export class SafeHtmlPipe implements PipeTransform {
constructor(private sanitized: DomSanitizer) {}
  transform(value) {
        return this.sanitized.bypassSecurityTrustHtml(value);
    }

}

Answer 2

this should work too:

component.html

<div #template></div>

component.ts

@ViewChild('template') myTemplate: ElementRef;

addTemplate(){
   this.myTemplate.nativeElement.innerHTML = '<button type="button">click me</button>';
   this.myTemplate.nativeElement.addEventListener('click', this.openAlert);
}

Answer 3

Basically this will not work. When you write code in Angular, it is transpiled by webpack and converted to javascript that is executed in the browser.

However, now you are injecting Angular code dynamically and not build ing it. The event detection (click) would not work natively and the function openAlert is also not in the global scope where it is injected. You will have to consider a different approach and generate content using <ng-template> based on response from the API .