Rails - Dec 2005 - HOW DO I populate options from previous option click

Hi,
I have a form with three drop down option lists. Currently each of these 
  contain full listings as instantiated in the controller on entering 
the edit action. What I would like to do is filter the second list based 
on what the user selected on the first and the third filtered to reflect 
the second.
For example I have major_role, role and person_in_role = role is a 
subset of major_role and person_in_role is one qualified to act in role
Kind Regards,
Eric

Eric:

I figure that even if my answer is semi useless, it is still better  
than no answer.  I hope you agree.  And with that out the way, here  
is the help I can offer.

It seems to me that there are three ways to achieve the effect you want.

1.  A round trip to the server. That would be easy, so I doubt that  
is what you want.

2. Some hideously complex javascript stuff that I still have  
nightmares about since I last had to do something like this.  (I  
believe debugging javascript has improved since then, firefox is your  
friend).

3.	Some wonderful ajax stuff.  Sadly, this is where I become  
completely useless to you since I have been focusing on other aspects  
of rails thus far.  From what I have read and seen, ajax is going to  
be nicer to you than doing javascript and nicer to the customers than  
round-tripping.

bruce






On 15-Dec-05, at 5:58 PM, Eric Sloane wrote:
> Hi,
> I have a form with three drop down option lists. Currently each of  
> these  contain full listings as instantiated in the controller on  
> entering the edit action. What I would like to do is filter the  
> second list based on what the user selected on the first and the  
> third filtered to reflect the second.
> For example I have major_role, role and person_in_role = role is a  
> subset of major_role and person_in_role is one qualified to act in  
> role
> Kind Regards,
> Eric
>
> _______________________________________________
> Rails mailing list
> Rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
> http://lists.rubyonrails.org/mailman/listinfo/rails

Change this according to your own needs:

1) View:

<%= select_tag(''search[category]'', SELECT OPTIONS HERE)
%>
<div id="sub_category_wrapper"></div>

<%= observe_field ''search[category]'', :url => {:action
=>
''search_sub_category_xhr''}, :update =>
''sub_category_wrapper'', :with
=> "''category_id='' + escape(value)", :complete
=> visual_effect
(:highlight, ''sub_category_wrapper'') %>

2) Now create a new action "search_sub_category_xhr"

   def search_sub_category_xhr
     if params[:category_id] =~ /^[0-9]+$/
       @sub_categories = Category.find(params[:category_id]).children
       render :action => ''search_sub_category_xhr'', :layout
=> false
     end

     if @sub_categories.empty?
       render :nothing => true
     end
   end

3) View for "search_sub_category_xhr"

<%= select_tag ''search[sub_category]'',  
options_from_collection_for_select(@sub_categories, ''id'',
''name'') %>





On Dec 16, 2005, at 1:58 AM, Eric Sloane wrote:
> Hi,
> I have a form with three drop down option lists. Currently each of  
> these  contain full listings as instantiated in the controller on  
> entering the edit action. What I would like to do is filter the  
> second list based on what the user selected on the first and the  
> third filtered to reflect the second.
> For example I have major_role, role and person_in_role = role is a  
> subset of major_role and person_in_role is one qualified to act in  
> role
> Kind Regards,
> Eric
>
> _______________________________________________
> Rails mailing list
> Rails-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>