kompass/modules/event-participants/Controllers/class-updateevent.php

<?php
namespace Bdp\Modules\EventParticipants\Controllers;

class UpdateEvent {
	public function __construct() {
		global $_POST, $_REQUEST, $dbHandler;

        $use_data = ['event_name', 'event_email', 'startdatum', 'enddatum','max_participants', 'max_volunteers', 'amount_reduced', 'amount_default', 'amount_social', 'contributing_tribes'];
        $post_data = [];
        foreach ($_POST as $key => $value) {
            if (in_array($key, $use_data)) {
                $post_data[$key] = $value;
            }
        };

        $post_data['amount_reduced'] = str_replace(',', '.', $_POST['amount_reduced']);
        $post_data['amount_default'] = str_replace(',', '.', $_POST['amount_default']);
        $post_data['amount_social'] = str_replace(',', '.', $_POST['amount_social']);

        $post_data['contributing_tribes'] = serialize( explode(PHP_EOL, $post_data['contributing_tribes'] ) );

		$dbHandler->updateRows(
			'kompass_veranstaltungen_index',
			$post_data,
			['id' => $_REQUEST['event-id']]
		);
		kompass_print_message_box(__('Event data updated successfull.', BDP_LV_PLUGIN_SLUG));
        new EditEvent();
	}
}