propertyOfNonObject.php

<?php

    /**
     * function that gets the formatted
     * string for event instances (gridview).
     * It will format a recursion instance set
     * or additional date set. If additional date set
     * It will get either the base event's ID or it's
     * own ID, if it's the base event.
     * 
     * @return bool|string
     */
    public function getDateRange(){
        if($this->Recursion){
            $dateRange = self::generateDaysString($this) . ' | ' . date('F jS',
                    strtotime($this->StartDate)) . ' - ' . date('F jS',
                    strtotime($this->RecursionEndDate)) . $this->getNiceStartTime();
            if ($this->getNiceEndTime()) {
                $dateRange .= ' to ' . $this->getNiceEndTime();
            }
        }else{
            $id = ($this->BaseEventID) ? $this->BaseEventID : $this->ID;
            $next = AdditionalDate::get()->filter(array(
                'Date:GreaterThanOrEqual' => date('Y-m-d'),
                'EventID' => $id
            ))->sort('Date')->first();
            $nextID = $next->ID;//errors here
            $otherDates = AdditionalDate::get()->filter(array(
                'Date:GreaterThanOrEqual' => date('Y-m-d'),
                'EventID' => $id
            ))->exclude(array('ID' => $nextID))->sort('Date');
            $monthCheck = null;
            $dateRange = '';
            $find = ',';
            $buildString = function ($date) use (&$monthCheck, &$dateRange, $find) {
                if (date('m', strtotime($date->Date)) == $monthCheck) {
                    $dateRange .= ', ' . date('jS', strtotime($date->Date));
                } else {
                    $dateRange = preg_replace('/(,(?!.*,))/', ' &', $dateRange);
                    $dateRange .= ($dateRange == '') ? date('F jS', strtotime($date->Date)) : ', ' . date('F jS',
                            strtotime($date->Date));
                    $monthCheck = date('m', strtotime($date->Date));
                }
            };
            $otherDates->each($buildString);
        }

        return ($dateRange != '') ? $dateRange : false;

    }