focusOnOpenChild property

  1. @ContentChild('focusOnOpen')
  2. @Input('focusOnOpen')
set focusOnOpenChild (Object? element)

Sets the focus child so that we can focus on it when the panel opens.

Implementation

@ContentChild('focusOnOpen')
@Input('focusOnOpen')
set focusOnOpenChild(Object? element) {
  // TODO: Need further investigation on why ElementRef is received instead of Element
  if (element is Focusable) {
    _focusOnOpenChild = element;
  } else if (element is Element) {
    _focusOnOpenChild = RootFocusable(element);
  } else if (element is ElementRef) {
    _focusOnOpenChild = RootFocusable(element.nativeElement);
  } else {
    assert(
        element == null,
        'Warning expansion panel content has a #focus'
        'child which is not an Element, or Focusable');
  }
}