I am unsure whether this is a bug or me being dumb, but when I add an <ucw:select field that allows multiple values like this:

         (<ucw:select :multiple t :accessor (slot-value page 'testslot)
                      (<ucw:option :value 1 "a")
                      (<ucw:option :value 2 "b")
                      (<ucw:option :value 3 "c"))

...the select element will indeed allow multiple rows to be selected, and the value that is put into the component slot is indeed a list instead of a single value, but it only contains one element, even when I select multiple elements before submitting. How do I fix this?

Thanks,
Marijn

Hi again,

After happily playing with the <ucw:select, <ucw:text etc tags and there :accessors for a while, I came across situations where I needed to have javascript read and write to the value of such elements client-side. Since their values all seem to contain mysteriously hashed strings, this will not work. Is there a way around this? For example a way to turn off the hashing (it seems that is only necessary if you want to store lisp objects in them). Right now I'm messily working around them by using normal input fields and reading the post values from the request in order to store them in my component again... basically re-implementing the :accessor functionality.

Also, it seems that there is no way to get at the parameters of a request object without using internal ucw symbols. Is this intentional, or also a case of forgetting to export a symbol?

That being said, this framework really rocks. Coming from PHP, it's a delight to use.

Regards,
Marijn

Hi,

Following is a field class for select elements that allow you to select more than one options. Unless I missed something, there is no class yet for select elements like that. This could be added to components/form.lisp to implement that. BUT, you'll probably notice the really ugly hack with the hidden input whose callback grabs all the values for the select input out of the parameters. If there is a better way to run code when a request is made I'd like to hear about it, so I can make a prettier implementation.

Maybe the callback mechanism needs some rethinking anyway? The (setf (client-value field) nil) in the render method of checkbox-field is also a case of code that should always be run before the parameters are handled, and does not really belong in a render method. Maybe add a way to register special callbacks for a form that allways run before the other callbacks? It seems forms already add a hidden variable to identify themselves, that could be used to decide which form-specific callbacks are run.

Currently normal callbacks are not form-specific, are they? I mean, if there are two forms on a page, and both have a field called 'name', will the two callbacks for those fields coexist peacefully or will they override each other?

Also, did you know that many xxx-field classes ignore the :name slot and just generate a random name (though make-new-callback)? Is this a bug or a feature?

Well, here's the code, for what it's worth:

(defclass multiple-select-field (select-field)
  ()
  (:default-initargs :name (random-string 8) :client-value ()))

(defmethod render ((field multiple-select-field))
  (<:ai (value field))
  (<:input :type "hidden" :value "x"
           :name (make-new-callback
                  (lambda (value)
                    (declare (ignore value))
                    (do ((vars (slot-value (context.request *context*) 'parameters) (cdr vars))
                         (result ()))
                        ((null vars) (setf (client-value field) result))
                      (if (string= (caar vars) (name field))
                          (push (cdar vars) result))))))
  (<:select :name (name field) :tabindex (tabindex field) :multiple t
            (setf (data-map field) (build-data-map field))
            (render-options field)))

(defmethod render-options ((field multiple-select-field))
  (dolist* ((key-string . value) (data-map field))
    (<:option :value key-string
              :selected  (member key-string (client-value field) :test #'string=)
              (render-value field value))))

(defmethod value ((field multiple-select-field))
  (mapcar (lambda (x)
            (cdr (assoc x (data-map field) :test #'string=)))
          (client-value field)))