I was going through tutorial #5, and decided that I would like to see if the admin panel scaffolding could easily show a dropdown of choices when presented with a has_many datamodel relationship.

So I decided to make Student has_many Nationality, and promote nationality from a simple text field to a database object. Then I found a class called "DropdownField_withAdd"... and got so far as to having the "Add Student" popup link in the CMS display a dropdown called "Nationality"... but of course the dropdown is empty, and I don't see a way to get it to give me the option of creating new nationalities....

Here's the relevant code I created:

class Student extends DataObject {

    static $db = array(
        'FirstName'     => 'Text',
        'LastName'      => 'Text'
    );

    static $has_one = array(
        'Mentor' => 'Mentor',
        'Nationality' => 'Nationality'
    );

    public function getCMSFields_forPopup(){
        $fields = new FieldSet();
        $fields->push(new TextField('FirstName', 'First Name'));
        $fields->push(new TextField('LastName', 'Last Name'));

        $Nationalities = Nationality::get('Nationality');

        $Nationalities_array = array();
        if ($Nationalities)
            foreach ($Nationalities as $Nationality)
                $Nationalities_array[$Nationality->getField('ID')]
                    = $Nationality->getField('Nationality');

        $fields->push(
            new DropdownField_withAdd(
                'Nationality',
                'Nationality',
                $Nationalities_array,
                'addLink'
            )
        );

        return $fields;
    }

}




-------------------------------------



class Nationality extends DataObject {

    static $db = array(
        'Nationality' => 'Text'
    );
    
    public function getCMSFields_forPopup(){
        $fields = new FieldSet();
        $fields->push(new TextField('Nationality', 'Nationality'));
        return $fields;
    }

}