export_form.php

<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**
 * @package local_lom
 * @copyright Zhifen Lin 2018 project OER Humboldt University Berlin 
 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

defined('MOODLE_INTERNAL') || die();

require_once($CFG->libdir . '/formslib.php');

class export_form extends moodleform {
    //Add elements to form
    public function definition() {
        global $CFG;
 
        $mform = $this->_form; // Don't forget the underscore! 
        
        $mform->addElement('hidden', 'id', '');
        $mform->setType('id', PARAM_INT);
        $mform->setDefault('id', $this->_customdata['id']);
        $id = $this->_customdata['id'];
                
        $this->add_action_buttons(false, get_string('go'));
        $this->set_data(array('id' => $id));
    }
    
    //Custom validation should be added here
    function validation($data, $files) {

        return array();
    }
}