function CategorySelectControl(CategoryCollection $o_categories, $page_valid = null)
{
# set properties
parent::XhtmlSelect('category', null, $page_valid);
$this->SetBlankFirst(true);
# add categories
$a_categories = $o_categories->GetItems();
foreach ($a_categories as $o_category) {
$o_opt = new XhtmlOption($o_category->GetName(), $o_category->GetId());
$o_opt->AddAttribute('style', 'padding-left: ' . ($o_category->GetHierarchyLevel() - 1) * 20 . 'px');
$this->AddControl($o_opt);
unset($o_opt);
}
}