Forum OpenACS Development: tcl newbie question: where does category_ids come from

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1: tcl newbie question: where does category_ids come from
Posted by Jeroen van Dongen on 06/23/04 12:11 AM
I'm working on adding categories support to file-storage, and while figuring out how to add a category selection list to the file-add form, I stumbled across some code in 'project-manager' that did what I wanted, see below:

if {![empty_string_p [category_tree::get_mapped_trees $package_id]]} {
    ad_form -extend -form {
  {category_ids:integer(category),multiple,optional {label "Categories"}
      {html {size 7}} {value {}}
}

This works. No problem there. And I mostly get what's going on. However where does that 'category_ids' variable (?) come from?

'get_mapped_trees' does not seem to set it or return it. The only place where it seems to be set is in 'categories::get_categories' but that is called nowhere in my code (at least not that I'm aware of).

BTW: the example code in the package developers docu does not seem to give the desired result (the result from that code being an empty select box with a single character 'f' as label). Or I must have done some *really* stupid things while adapting the code for my case, but ...

I'd really appreciate some light on this issue.

Thanks in advance,
JvD

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2: Re: tcl newbie question: where does category_ids come from (response to 1)
Posted by Jeff Davis on 06/23/04 03:27 PM
The trick is that the category widget looks up the information from the database. If you are mapping a new item values is empty otherwise it has [list $object_id $container_id] (well, actually that is deprecated -- they are supposed to be passed as attributes category_application_id and category_object_id now, but project manager uses the old form).

Look at template::widget::category for the gory details.

You could also look at lars-blogger for a somewhat higher level interface which handles creating multiple form elements if you have multiple trees mapped.

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3: Re: tcl newbie question: where does category_ids come from (response to 2)
Posted by Jeroen van Dongen on 06/23/04 09:54 PM
Thanks ... I'm getting the picture. Talking about side-effects ... 😊