How to use
.
import {AfterViewInit, Component, Directive, ViewChild} from '@angular/core';
@Directive({selector: 'child-directive'})
class ChildDirective {
}
@Component({selector: 'someCmp', templateUrl: 'someCmp.html'})
class SomeCmp implements AfterViewInit {
@ViewChild(ChildDirective) child: ChildDirective;
ngAfterViewInit() {
// child is set
}
}
Description
You can use ViewChild to get the first element or the directive matching the selector from the
view DOM. If the view DOM changes, and a new child matches the selector,
the property will be updated.
View queries are set before the ngAfterViewInit
callback is called.
Metadata Properties:
- selector - the directive type or the name used for querying.
- read - read a different token from the queried elements.
import {Component, Directive, Input, ViewChild} from '@angular/core';
@Directive({selector: 'pane'})
export class Pane {
@Input() id: string;
}
@Component({
selector: 'example-app',
template: `
<pane id="1" *ngIf="shouldShow"></pane>
<pane id="2" *ngIf="!shouldShow"></pane>
<button (click)="toggle()">Toggle</button>
<div>Selected: {{selectedPane}}</div>
`,
})
export class ViewChildComp {
@ViewChild(Pane)
set pane(v: Pane) {
setTimeout(() => { this.selectedPane = v.id; }, 0);
}
selectedPane: string = '';
shouldShow = true;
toggle() { this.shouldShow = !this.shouldShow; }
}
npm package: @angular/core
exported from core/index defined in core/src/metadata/di.ts