Allows TActiveDropDownList and TActiveListBox to add new options
during callback response. New options can only be added after the
{@link TControl::onLoad OnLoad} event.
The {@link getListHasChanged ListHasChanged} property is true when the
list items has changed. The control responsible for the list needs to
repopulate the client-side options.
/**
* Creates a collection object to hold list items. A specialized
* TActiveListItemCollection is created to allow the drop down list options
* to be added.
* This method may be overriden to create a customized collection.
* @return TActiveListItemCollection the collection object
*/
protected function createListItemCollection()
{
$collection = new TActiveListItemCollection();
$collection->setControl($this);
return $collection;
}
