Validate a form: in-validator error

The CMS Questions
1

Hello,

I’m trying to create an order form and used the following example from @bastianallgeier: Plain contactform example for Kirby 2 · GitHub.
I want to compare a city name with an array of valid city names and want to use the ‘in-validator’ (Kirby 2 Docs) like this:

$invoice_address_delivery_rules = array('City' => array('required', 'match' => '/[A-Za-z0-9]+/', 'in' => ['City1','City2','City3']));

Unfortunately I get the following error message after submitting the form and can’t find a solution yet.

Whoops \ Exception \ ErrorException (E_WARNING)
in_array() expects parameter 2 to be array, string given

Any ideas or solutions?
Thank you!

2

Is there are stack trace?

3

I hope this will help!

 Whoops\Exception\ErrorException 
    …/vendor/getkirby/toolkit/lib/v.php:88
    12
     in_array
    …/vendor/getkirby/toolkit/lib/v.php:88
    11
     {closure}
    …/vendor/getkirby/toolkit/lib/v.php:41
    10
    V __callStatic
    …/vendor/getkirby/toolkit/helpers.php:282
    9
     call
    …/vendor/getkirby/toolkit/helpers.php:353
    8
     invalid
    /Users/noctua/www/projekt1/site/controllers/shopping_cart.php:254
    7
    Kirby\Registry\Controller {closure}
    …/core/page.php:1515
    6
    PageAbstract controller
    …/kirby/component/template.php:35
    5
    Kirby\Component\Template data
    …/kirby/component/template.php:87
    4
    Kirby\Component\Template render
    …/kirby.php:681
    3
    Kirby template
    …/kirby.php:669
    2
    Kirby render
    …/kirby/component/response.php:29
    1
    Kirby\Component\Response make
    …/kirby.php:751
    0
    Kirby launch
    /Users/noctua/www/projekt1/index.php:16
4

The syntax must be different, see here: How to get and send radio and select data from a form to an email?