public function isAllDay()
    {
        if ($this->AllDay) {
            return true;
        }

        $secsInDay = 60 * 60 * 24;
        $startTime = strtotime($this->StartDateTime);
        $endTime = strtotime($this->EndDateTime);

        if (($endTime - $startTime) > $secsInDay) {
            return true;
        }
    }