public static function checkNecessaryFieldsDelete($itemtype, $field)
 {
     $type = new PluginGenericobjectType();
     $type->getFromDBByType($itemtype);
     if ($type->canUseNetworkPorts() && 'locations_id' == $field) {
         return false;
     }
     /*
           if ($type->fields['use_direct_connections']) {
              foreach(array('users_id','groups_id',' states_id','locations_id') as $tmp_field) {
                 if ($tmp_field == $field) {
                    return false;
                 }
              }
           }*/
     return true;
 }