Can`t get access to component categories - Joomla! Forum - community, help and support

can`t access categories of component
it works( in model )

code: select all

$category = jcategories::getinstance('content');
$cat = $category->get('root');


but if try :

code: select all

$category = jcategories::getinstance('mycomponent');
$cat = $category->get('root');


or

code: select all

$options['table'] = '#__mycomponent';
$options['extension'] = 'com_mycomponent';
$categories = jcategories::getinstance('mycomponent', $options);


it doesn`t works