Rails - Sep 2005 - Where to place find_all

Hi,

I''m using a "collection_select" form-helper in a view:

<%= collection_select(''product'',
''sub_category_id'', @sub_categories,
''id'', ''name'') %>

In the appropriate action in the controller I also have:

@sub_categories = SubCategory.find_all

However, I get a NoMethodError and the message:

WARNING:  You have a nil object when you probably didn''t expect it! 
Odds are you
want an instance of Array instead.

If I move the line that populates @sub_categories directly into my view, to get:

<%= @sub_categories = SubCategory.find_all %>
<%= collection_select(''product'',
''sub_category_id'', @sub_categories,
''id'', ''name'') %>

the view works and I get the selection list I expect.

Can anyone explain to me why it works in the view but not in the
controller? Everything I''ve read seems to say that the @sub_categories
= SubCategory.find_all line should be in the controller.

Sorry for what is undoubtedly a simple question but I really don''t
seem to be able to find an answer to this elsewhere.

Cheers! :)

-- 
Matthew Revell
www.understated.co.uk

On 21/09/05, Matthew Revell
<matthew.revell-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
wrote:
>
> @sub_categories = SubCategory.find_all
>
> However, I get a NoMethodError and the message:
>
> WARNING:  You have a nil object when you probably didn''t expect
it!
> Odds are you
> want an instance of Array instead.
I did wonder if this might be because I didn''t have:

model :sub_category

at the top of the controller. However, even with that in place I''m
getting the nil object error.

I can only assume that the SubCategory model isn''t loaded at the point
where I try to populate @sub_categories. Should I be using eager
loading, or have I got the wrong end of the stick there?

Cheers.

--
Matthew Revell
www.understated.co.uk