Rails documentation gives examples of using option_groups_from_collection_for_select with two tables/objects.
How could it be done with one?
Example that almost works:
I have a form to enter address from both the United States and Canada. It has the following:
====new.html.erb==== <%= select_tag( :state, option_groups_from_collection_for_select( State.countries, :country, :country, "id", "id")) %>
Just use options_from_collection_for_select
Julian.
Learn Ruby on Rails! Check out the FREE VIDS (for a limited time)
VIDEO #3 out NOW!
http://sensei.zenunit.com/
Ok, that and some reading has gotten me to this:
====app/views/wherever/new.html.erb==== <%= render(:partial => "states/state") %>
The only example that I've seen of this is in AWD Ch. 22 (p. 488 printed), and it seems to be a lot of work. The book wraps the option_groups_from_collection_for_select in <select> tags (html, not a helper). The first parameter given is the highest level array - in your case, it would essentially be [ "Canada", "US" ] - but each value in the array is another object (a class in the example) with the group name and sub-options available through attr_reader methods.
It seems like a lot of work. If you want to do it the "good" way, read more of the API on option_groups_from_collection_for_select (I think that you were on the right track for what you want to do). Since you only have two groups, you could also do a little hard-coding and use helpers to get the states.
-Kyle