protected function _init()
 {
     parent::_init();
     // create a filterquery
     $fq = $this->createFilterQuery();
     $fq->setKey('maxprice');
     $fq->setQuery('price:[1 TO 300]');
     // and add it
     $this->addFilterQuery($fq);
 }
 protected function _init()
 {
     parent::_init();
     // create a filterquery
     $this->createFilterQuery('maxprice')->setQuery('price:[1 TO 300]');
 }