Sunday 18 February 2024

What is the difference between Content Child & Content Children Angular ? 99

 What is the difference between Content Child & Content Children Angular ?

In Angular, both ContentChild and ContentChildren are decorators used to interact with content projected into a component using <ng-content>, but they serve different purposes and have key distinctions:


  • Retrieves a single element or directive from the projected content.

  • Requires a reference variable assigned to the projected content or a specified type of element/directive.

  • Useful for accessing specific pieces of projected data or functionality.

  • Returns the matching element/directive as a property in your component class.


  • Retrieves an array of elements or directives matching a selector or type from the projected content.

  • Can be used even without reference variables, just based on the element/directive type.

  • Useful for iterating over or manipulating multiple elements from the projected content.

  • Returns a QueryList, which is an observable collection that updates dynamically as the content changes.

Key Differences:




Number of elements

Retrieves a single element

Retrieves an array of elements

Return type

Instance of the element/directive

QueryList (observable collection of elements)

Reference variable

Can use reference variable or type

Uses selector or type, reference variable optional

Use cases

Single element access, specific manipulation

Multiple elements, iteration, dynamic changes response



// Parent component template
  <p #specificContent>This is specific content.</p>
  <div *ngFor="let item of items">
    <p>{{ item }}</p>

// Child component template
  <h2>{{ title }}</h2>


// Child component
@Component({ /* ... */ })
export class MyChildComponent {
  @ContentChild('specificContent') content: ElementRef; // Single element with reference variable
  @ContentChildren(ParagraphElement) paragraphs: QueryList<ParagraphElement>; // Array of matching elements by type

  ngAfterViewInit() {
    console.log(this.content.nativeElement.textContent); // Outputs: "This is specific content."
    this.items.forEach(item => console.log(item.nativeElement.textContent)); // Iterate over each paragraph


  • Use ContentChild when you need access to a specific element or directive within the projected content.

  • Use ContentChildren when you need to work with multiple elements or respond to changes in the projected content.

  • Leverage the QueryList provided by ContentChildren for dynamic management of the retrieved elements.

By understanding the differences and appropriate use cases of ContentChild and ContentChildren, you can effectively interact with projected content in your Angular components, enhancing their flexibility and functionality.

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