PHP - 使用 OOP 将入口添加到 Mysql 表中

我想使用 POO 将入口（使用表单）添加到 Mysql 表中。这是我所做的：我的班级 ：

<?php
class portfolio{
    public $title;
    public $img_desk;
    public $img_tablet;
    public $img_phone;
    public $id;
    public function __construct($title, $img_desk, $img_tablet, $img_phone, $port_id){
        $this->title = $title;
        $this->img_desk = $img_desk;
        $this->img_tablet = $img_tablet;
        $this->img_phone = $img_phone;
        $this->id = $port_id;
    }
    public function getPortfolio($id){
        $reponse = $bdd->query('SELECT * FROM designer WHERE id = $id');
        $portfolio = $reponse->fetch();
        $a = new portfolio($portfolio['title'], $portfolio['img_desk'], $portfolio['img_tablet'], $portfolio['phone'], $portfolio['id']);
        return $a;
    }
    public function addPortfolio($title, $img_desk, $img_tablet, $img_phone){
        $add = $bdd->exec('INSERT INTO designer(title, img_desk, img_tablet, img_phone) VALUES(:title, :img_desk, :img_tablet, :img_phone)');
        $add->execute(array(  // _> was used.!!!
            'title' => $title,
            'img_desk' => $img_desk['name'],
            'img_tablet' => $img_tablet['name'],
            'img_phone' => $img_phone['name']
            // imgs...
        ));
        if (isset($img_desk) AND $img_desk['error'] == 0){
                // Testons si le fichier n'est pas trop gros
                if ($img_desk['size'] <= 3000000)
                {
                        require("class/img.class.php");
                        // Testons si l'extension est autorisée
                        $infosfichier = pathinfo($img_desk['name']);
                        $extension_upload = $infosfichier['extension'];
                        $extensions_autorisees = array('jpg', 'jpeg', 'gif', 'png');
                        if (in_array($extension_upload, $extensions_autorisees))
                        {
                                // On peut valider le fichier et le stocker définitivement
                                move_uploaded_file($img_desk['tmp_name'], 'img/port/' . basename($img_desk['name']));
                        }   
                }
        }
        echo 'Élement ajouté';
    }
    public function editPortfolio($old, $new){
        $edit = $bdd->prepare('UPDATE designer SET title = :title, img_desk = :img_desk, img_tablet = :img_tablet, img_phone = :img_phone WHERE id = $old->id ');
        $edit->execute(array(
            'title' => $new->title,
            'img_desk' => $new->img_desk,
            'img_tablet' => $new->img_tablet,
            'img_phone' => $new->img_phone
            ));
    }
    public function deletePortfolio($cible){
        //DELETE FROM designer WHERE id = $cible->id;
    }
    public function getAllPortfolio(){
        //$reponse = $bdd->query('SELECT * FROM designer');
        //$donnees = $reponse->fetch();
        //return $donnees;
    }
}
?>

这是我在包含以下形式的 php 文件上使用的：

<?php
include('class/portfolio.class.php');
        if(isset($_POST['title'])){
            addPortfolio($_POST['title'], $_FILES['img_desk'], $_FILES['img_tablet'], $_FILES['phone']);
            echo 'ok';
        }else{
            ?>
            <form method="post" action="admin.php" enctype="multipart/form-data">
                <input type="text" placeholder="Titre" name="title"><br>
                <input type="file" name="img_desk"><br>
                <input type="file" name="img_tablet"><br>
                <input type="file" name="img_phone"><br>
                <input type="submit" value="Ajouter" name="ok">
            </form>
            <?php
        }
        ?>

它告诉我：

Fatal error: Call to undefined function addPortfolio() in C:'wamp'www'designers'admin.php on line 47

有人可以解释一下吗？我知道我做错了，但我实际上正在学习OOP。提前谢谢你：）。