@viewChild not working - cannot read property nativeElement of undefined

Question

I\'m trying to access a native element in order to focus on it when another element is clicked (much like the html attribute \"for\" - for cannot be used on elements of th

Answer 1

Initializing the Canvas like below works for TypeScript/Angular solutions.

const canvas = <HTMLCanvasElement> document.getElementById("htmlElemId"); 

const context = canvas.getContext("2d"); 

Answer 2

You'll also get this error if your target element is inside a hidden element. If this is your HTML:

<div *ngIf="false">
    <span #sp>Hello World</span>
</div>

Your @ViewChild('sp') sp will be undefined.

Solution

In such a case, then don't use *ngIf.

Instead use a class to show/hide your element being hidden.

<div [class.show]="shouldShow">...</div>

Answer 3

@ViewChild('keywords-input') keywordsInput; doesn't match id="keywords-input"

id="keywords-input"

should be instead a template variable:

#keywordsInput

Note that camel case should be used, since - is not allowed in template reference names.

@ViewChild() supports names of template variables as string:

@ViewChild('keywordsInput') keywordsInput;

or component or directive types:

@ViewChild(MyKeywordsInputComponent) keywordsInput;

See also https://stackoverflow.com/a/35209681/217408

Hint:
keywordsInput is not set before ngAfterViewInit() is called

Answer 4

it just simple :import this directory

import {Component, Directive, Input, ViewChild} from '@angular/core';

Answer 5

What happens is when these elements are called before the DOM is loaded these kind of errors come up. Always use:

 window.onload = function(){
     this.keywordsInput.nativeElement.focus();
 }

Answer 6

The accepted answer is correct in all means and I stumbled upon this thread after I couldn't get the Google Map render in one of my app components.

Now, if you are on a recent angular version i.e. 7+ of angular then you will have to deal with the following ViewChild declaration i.e.

@ViewChild(selector: string | Function | Type<any>, opts: {
read?: any;
static: boolean;
})

Now, the interesting part is the static value, which by definition says

• static - True to resolve query results before change detection runs

Now for rendering a map, I used the following ,

@ViewChild('map', { static: true }) mapElement: any;
  map: google.maps.Map;