[racket] label-string

Ahhhh,
ok thank you very much. By the way, when I make a tab-panel with multiple tabs and add a list-box to the tab-panel it appears on all tab pages. So how can I specify the tab/tabindex as parent to the list-box?
And is it possible to init the list-box with more choices as one. In the example in the doc there is a initialisation only for one column. I would like to init say 4 columns with data(as vector or map??).
For this I don´t found any example, and I hope you could give me the place where it stays or an suggestion..

Yours,

-------- Original-Nachricht --------
> Datum: Thu, 20 Dec 2012 12:44:52 +0100
> Von: Laurent <laurent.orseau at gmail.com>
> An: murat demirtas <heraklea at gmx.de>
> CC: racket <users at racket-lang.org>
> Betreff: Re: [racket] label-string

> Hi,
> 
> From the Help Desk:
> (new tab-panel%
>     [choices choices]
> [...]
> 
>  → (is-a?/c tab-panel%)
>   choices : (listof label-string?)
> 
> So it wants a list of label-string.
> Then clicking on `label-string?` gives:
> 
> """
> (label-string? v) → boolean?
> 
>   v : any/c
> Returns #t if v is a string whose length is less than or equal to 200.
> 
> This predicate is typically used as the contract for strings that appear
> in
> GUI objects. In some cases, such as the label in a button% or menu-item%
> object, the character & is treated specially to indicate that the
> following
> character is used in keyboard navigation. See set-label in
> labelled-menu-item<%> for one such example. In other cases, such as the
> label on a frame%, & is not treated specially.
> """
> 
> So you could do the following:
> 
> (define tab-panel (new tab-panel%
>                        (parent dialog)
>                        (choices (map ~a (vector->list Vec)))))
> 
> Laurent
> 
> On Thu, Dec 20, 2012 at 12:19 PM, <heraklea at gmx.de> wrote:
> 
> > Hello friends,
> >
> > how can I convert a vector  (define Vec #(1 2 3 4))
> >
> > to a label-string to make a tab-panel??
> >
> > I try this
> > (define tab-panel (new tab-panel%
> >                        (parent dialog)
> >                        (choices (vector->list Vec))))
> >
> > but it fails due to contract violation: expected: label-string?
> >
> > So what ist a label-string???
> >
> >
> > Yours,
> > ____________________
> >   Racket Users list:
> >   http://lists.racket-lang.org/users
> >