References
Oleksa Novyk | GitHub

@ViewChildren

This is the documentation for Angular 6.
You can switch to the latest version Angular 9.

You can use ViewChildren to get the QueryList of elements or directives from the view DOM. Any time a child element is added, removed, or moved, the query list will be updated, and the changes observable of the query list will emit a new value.

View queries are set before the ngAfterViewInit callback is called.

Example

import {AfterViewInit, Component, Directive, QueryList, ViewChildren} from '@angular/core';

@Directive({selector: 'child-directive'})
class ChildDirective {
}

@Component({selector: 'someCmp', templateUrl: 'someCmp.html'})
class SomeCmp implements AfterViewInit {
  @ViewChildren(ChildDirective) viewChildren: QueryList<ChildDirective>;

  ngAfterViewInit() {
    // viewChildren is set
  }
}
Links & Tutorials

Options

@ContentChildren(
  selector: Type<any>|Function|string, 
  opts?: {read?: any},
)

selector#

selector: Type<any>|Function|string

The directive type or the name used for querying.

Supported selectors include:

  • any class with the @Component or @Directive decorator
  • a template reference variable as a string (e.g. query <my-component #cmp></my-component> with @ViewChild('cmp'))
  • any provider defined in the child component tree of the current component (e.g. @ViewChild(SomeService) someService: SomeService)
  • any provider defined through a string token (e.g. @ViewChild('someToken') someTokenVal: any)
  • a TemplateRef (e.g. query <ng-template></ng-template> with @ViewChild(TemplateRef) template;)

opts#

opts?: {read?: any}

Additional options

  • read - read a different token from the queried elements.