Hello! I'm trying to use one Form for both "Add" and "Edit" Post pages. According to this docs page I use a Posts model to set default values in the form’s elements. Sadly something went wrong with Select element.

BlogPostConroller (EditAction):

  $form = new Form($post);


class AddBlogPostForm extends Form

public function initialize(\Project\Models\BlogPosts $post = null)

    $title = new Text('title', [
        'placeholder' => 'title'

    $title->setLabel('Title of the post');

        new PresenceOf([
            'message' => 'no title'
        new StringLength([
            'min' => 12,
            'messageMinimum' => 'Very short title'

    $title->setFilters(['trim', 'string']);


    $select = new Select("type", BlogTypes::find(),
                "using" => [

     $select->addValidator(new PresenceOf([
            'message' => ' Choose the post type'


    $this->add(new Submit('Add'));


I'm getting Catchable fatal error: Object of class Project\Models\BlogTypes could not be converted to string in \app\cache\volt\appviewsblogpostedit.volt.php on line 19 which referrences to


How does Form + entity interact with Select Element? How to solve my issue?