angular4 / typescript中的document.getElementById替换？

Question

So, im working with angular4 in my practice work and this is new for me. Luckyly, in order to get html elements and its values i used <HTMLInputElement> document.getElementById or <HTMLSelectElement> document.getElementById

Im wondering if there is any replacement for this in angular

Answer 1

You can tag your DOM element using #someTag , then get it with @ViewChild('someTag') .

See complete example:

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

@Component({
    selector: 'app',
    template: `
        <div #myDiv>Some text</div>
    `,
})
export class AppComponent implements AfterViewInit {
    @ViewChild('myDiv') myDiv: ElementRef;

    ngAfterViewInit() {
        console.log(this.myDiv.nativeElement.innerHTML);
    }
}

console.log will print Some text .

Answer 2

You can just inject the DOCUMENT token into the constructor and use the same functions on it

import { Inject }  from '@angular/core';
import { DOCUMENT } from '@angular/common'; 

@Component({...})
export class AppCmp {
   constructor(@Inject(DOCUMENT) document) {
      document.getElementById('el');
   }
}

Or if the element you want to get is in that component, you can use template references .

Answer 3

  element: HTMLElement;

  constructor() {}

  fakeClick(){
    this.element = document.getElementById('ButtonX') as HTMLElement;
    this.element.click();
  }

Answer 4

For Angular 8 or posterior @ViewChild have an additional parameter called opts, which have two properties: read and static, read is optional. You can use it like so:

@ViewChild('mydiv', { static: false }) mydiv: ElementRef;

Note this is for Angular 8 or posterior.