Rails - Jul 2005 - Dynamically generate form fields

I have a model with an array of items (has_many). I want to generate
form fields (for example a text area) for each of these items. Say that
each item has an attribute with the name "name" to be used as field
title and that the attribute named "content" is the one to be edited
(for each item). 

Is it possible to do with form helpers (and a loop over the items I
guess) and is update_attributes able to take care of the updating of
that kind of form? If possible, how? If not possible, what is the Rails
way of doing this? Can I use partials in some clever way?

/Marcus

-- 
Marcus Andersson
Dreampark AB <http://dreampark.se/>
Direct: +46 11 26 42 20
Mobile: +46 734 225 295

Trying to follow your example gives this (more or less) on update:

  def update
    @page = Page.find(params[:id])
    params[:content_item].each { |key, item|
      @page.content_items[key.to_i].attributes = item
      @page.content_items[key.to_i].save # <= disturbing
    }
    @page.attributes = params[:page]
    if @page.save
      flash[:notice] = ''Page was successfully updated.''
      redirect_to :action => ''show'', :id => @page
    else
      render :action => ''edit_content''
    end
  end

I''ve tried to loop through all content_items and just update their
attributes without doing the explicit save of each item. But, if I
don''t
do the save it won''t get updated when I do the @page.save.
Isn''t a save
to @page supposed to cascade to a has_many collection? Doing as I do now
I end up with lots of updates sent to the database (unless ActiveRecord
utilizes some smart write behind etc...) and that doesn''t feel very
good.

/Marcus

-----Original Message-----
From: Wilson [mailto:defiler-ifvz4xmYPRU@public.gmane.org] 
Sent: den 18 juli 2005 20:30
To: Marcus Andersson
Subject: Re: [Rails] Dynamically generate form fields

Our e-mails probably hit the list at almost the same moment, but check
out the example code I pasted up here:
http://supremetyrant.com/misc/rails/
new_members.rhtml and its partial form _member.rhtml do what you''re
describing, with an arbitrary number of indexed form fields via a
partial.

Marcus Andersson wrote:
> I have a model with an array of items (has_many). I want to generate 
> form fields (for example a text area) for each of these items. Say 
> that each item has an attribute with the name "name" to be used
as
> field title and that the attribute named "content" is the one to
be
> edited (for each item).
> 
> Is it possible to do with form helpers (and a loop over the items I
> guess) and is update_attributes able to take care of the updating of 
> that kind of form? If possible, how? If not possible, what is the 
> Rails way of doing this? Can I use partials in some clever way?
> 
> /Marcus
>