protected function getExtProperties()
 {
     $aProp = parent::getExtProperties();
     $aProp['autoLoad'] = true;
     $aProp['proxy'] = array('type' => 'ajax', 'url' => $this->url, 'reader' => array('type' => 'json'));
     return $aProp;
 }
 protected function getExtProperties()
 {
     $aProp = parent::getExtProperties();
     $aProp['data'] = $this->data;
     return $aProp;
 }