private function generateTempFile()
{
$tempfile = new TempFile($this->getStorage());
$file = new File($this->getStorage());
$file->setExportFilename("vpanel-chart-" . date("Y-m-d"));
$file->save();
$tempfile->setFile($file);
$tempfile->setTimestamp(time());
$tempfile->setUserID($this->getUserID());
$tempfile->save();
$this->tempfileids[] = $tempfile->getTempFileID();
return $tempfile;
}