From: Devin Mullins <twifkak@...>
Date: 2005-08-08T18:48:21+09:00
Subject: Re: on ruby on rails and forms

Andres,

To understand what's happening, you're going to have to look at HTML 
forms, and the queries it builds. (Use GET method instead of POST so you 
can look at it.) Your error has nothing to do with Rails, except in that 
it can't read the user's mind. I'm way too tired to explain right now, 
so start Googling. :) The short answer, if you want to stick with the 
same interface, is you're going to have to use some javascript to build 
up some hidden fields.

Whether you use AJAX to send the updated results back before the user 
even hits submit is up to you. But if you want to, the prototype library 
that comes with Rails should help.

Devin

Andres Montano wrote:

>Thanks for the quick reply Julian. I will provide more detail here.
>
>I have two tables: roles and permissions with a "has_and_belongs_to_many" 
>relationship between each other.
>
>In the edit action for role, I initialize role and permissions like this:
>
>    @role = Role.find(@params[:id])
>    @permissions = Permission.find (:all, :order => "title")
>
>In the model I have two lists: one with all the available permissions and 
>another with the permissions that a specific role has and buttons that move 
>stuff from one list to the other using javascript.
>
>The rhtml code for the lists goes like this:
>
><select id="available_permissions" name="available_permissions" multiple 
>size="10">
>  <% available_permissions = @permissions - @role.permissions %>
>  <%= options_for_select (available_permissions.collect { |p| [p.title, 
>p.id]}) %>
></select>
>
><select id="role_permissions" name="role[permissions][]" multiple = 
>"multiple" size="10">
>  <%= options_from_collection_for_select(@role.permissions, "id", "title") 
>%>
></select>
>
>I have two buttons invoke a javascript method to remove an item from one 
>list and add it to the other list. It goes like this:
>
>function moveSelected(orig, dest)
>{
> var selectOrig = document.getElementById(orig);
> var selectDest = document.getElementById(dest);
> var i = 0;
> while (i<selectOrig.length)
> {
>  option = selectOrig.options[i];
>  if (option.selected)
>  {
>   option.selected = false;
>   selectOrig.remove(i);
>   if (nn6)
>   {
>    selectDest.length = selectDest.length+1;
>    selectDest.options[selectDest.length-1] = option;
>   }
>   else selectDest.add(option);
>  }
>  else i++;
> }
>}
>
>This part works well with records that I added manually to the 
>permissions_roles intermediate table. Nevertheless the simple
>    if @role.update_attributes(@params[:role]) ...
>
>is not intelligent enough to populate role.permissions and update the tables 
>in the database. That is fine, as long as I can access the select options 
>from the controller, but whatever name I put in params doesn't seem to work. 
>The hash returned by @params[:role] or @params["role"] doesn't include 
>"permissions" (i.e. @params[:role]["permissions"] is nil). Changing the name 
>to something else like id = "assocperms" name = "assocperms[]" doesn't help 
>as @params["assocperms"] also is nil (and so is @params["assocperms[]"], 
>etc.). Also removing the "[]" from the name didn't do the trick. Is my only 
>alternative to wrap up the select list in a div, send it via a 
>form_remote_tag, and parse it manually? The must be a more elegant solution.
>
>If anyone can provide insight on how I can tackle this problem it will be 
>greatly appreciated!
>
>    Andres
>
>"Julian Leviston" <julian@coretech.net.au> wrote in message 
>news:EE4E8D2C-7BDA-41E2-86E2-AC2C6042A33A@coretech.net.au...
>  
>
>>Hi.
>>
>>I wonder if there's a rails list...
>>
>>Can you be more specific?
>>
>>So you've got your helper code down to create HTML select, that's  cool... 
>>but what do you mean by "use modifies the options via  javascript" - how?
>>
>>Julian.
>>
>>On 08/08/2005, at 12:01 PM, Andres Montano wrote:
>>
>>    
>>
>>>Does anybody know if the options for a select in a form are  accesible 
>>>via
>>>@params?
>>>
>>>I have an application that succesfully builds the select html  statements 
>>>but
>>>then the user modifies the options via javascript. When the form gets
>>>posted, is there a way to know what options are there, which are 
>>>selected,
>>>etc from the controller?
>>>
>>>I have tried all sorts of strategies like adding the [] to the name  of 
>>>the
>>>select tag, but however I name it, param always returns nil.
>>>
>>>Thanks,
>>>    Andres
>>>
>>>
>>>
>>>
>>>      
>>>
>>
>>    
>>
>
>
>
>
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>