core-bundle/src/Resources/contao/dca/tl_layout.php
public function getStyleSheets(Contao\DataContainer $dc)
	{
		$intPid = $dc->activeRecord->pid;

		if (Contao\Input::get('act') == 'overrideAll')
		{
			$intPid = Contao\Input::get('id');
		}

		$objStyleSheet = $this->Database->prepare("SELECT id, name FROM tl_style_sheet WHERE pid=?")
										->execute($intPid);

		if ($objStyleSheet->numRows < 1)
		{
			return array();
		}

		$return = array();

		while ($objStyleSheet->next())
		{
			$return[$objStyleSheet->id] = $objStyleSheet->name;
		}

		return $return;
	}
public function getStyleSheets(Contao\DataContainer $dc)
	{
		$intPid = $dc->activeRecord->pid;

		if (Contao\Input::get('act') == 'overrideAll')
		{
			$intPid = Contao\Input::get('id');
		}

		$objStyleSheet = $this->Database->prepare("SELECT id, name FROM tl_style_sheet WHERE pid=?")
										->execute($intPid);

		if ($objStyleSheet->numRows < 1)
		{
			return array();
		}

		$return = array();

		while ($objStyleSheet->next())
		{
			$return[$objStyleSheet->id] = $objStyleSheet->name;
		}

		return $return;
	}
Return all style sheets of the current theme

@param Contao\DataContainer $dc

@return array