/**
  * Get selectable columns
  *
  * @param
  * @return
  */
 function getSelectableColumns()
 {
     // default fields
     $cols = array();
     switch ($this->report) {
         case "exportSelectedCore":
             $cols = ilSCORMTrackingItems::exportSelectedCoreColumns($this->bySCO, $this->allowExportPrivacy);
             break;
         case "exportSelectedRaw":
             $cols = ilSCORMTrackingItems::exportSelectedRawColumns();
             break;
         case "exportSelectedInteractions":
             $cols = ilSCORMTrackingItems::exportSelectedInteractionsColumns();
             break;
         case "exportSelectedObjectives":
             $cols = ilSCORMTrackingItems::exportSelectedObjectivesColumns();
             break;
         case "tracInteractionItem":
             $cols = ilSCORMTrackingItems::tracInteractionItemColumns($this->bySCO, $this->allowExportPrivacy);
             break;
         case "tracInteractionUser":
             $cols = ilSCORMTrackingItems::tracInteractionUserColumns($this->bySCO, $this->allowExportPrivacy);
             break;
         case "tracInteractionUserAnswers":
             $cols = ilSCORMTrackingItems::tracInteractionUserAnswersColumns($this->userSelected, $this->scosSelected, $this->bySCO, $this->allowExportPrivacy);
             break;
         case "exportSelectedSuccess":
             $cols = ilSCORMTrackingItems::exportSelectedSuccessColumns();
             break;
     }
     return $cols;
 }