protected function getSortingFieldValue($data, $fields)
	{
		if(is_object($data))
		{
			foreach($fields as $field)
				$data=isset($data->$field) ? $data->$field : null;
		}
		else
		{
			foreach($fields as $field)
				$data=isset($data[$field]) ? $data[$field] : null;
		}
		return $this->caseSensitiveSort ? $data : mb_strtolower($data,Yii::app()->charset);
	}