全て。私はrails4 を使用していますが、 carmen-railsのドキュメントに従っていますが、国を選択するときに州のサブリージョンを機能させることができません。実際、サブリージョン コードをそのままにしておくと、サイトに移動することさえできません。次のエラーが表示されます。
localhost:3000
Processing by OrdersController#new as HTML
Rendered orders/_subregion_select.html.erb (1.9ms)
Rendered orders/_form.html.erb (773.3ms)
Rendered orders/new.html.erb within layouts/application (775.8ms)
Completed 500 Internal Server Error in 784ms
ActionView::Template::Error (undefined method `downcase' for nil:NilClass):
1: <div id="order_state_wrapper">
2: <% parent_region ||= params[:parent_region] %>
3: <% country = Carmen::Country.coded(parent_region) %>
4:
5: <% if country.nil? %>
6: <em>Please select a country above</em>
app/views/orders/_subregion_select.html.erb:3:in `_app_views_orders__subregion_select_html_erb__937058573181156642_69893053026600'
app/views/orders/_form.html.erb:100:in `block in _app_views_orders__form_html_erb__3775537416523760398_69893046471120'
app/views/orders/_form.html.erb:1:in `_app_views_orders__form_html_erb__3775537416523760398_69893046471120'
app/views/orders/new.html.erb:6:in `_app_views_orders_new_html_erb__3931135682021831649_69893046299220'
(国、この場合は「US」) パラメータが「nil」であるため、親リージョンから渡されているようには見えません。これを機能させるための洞察はありますか（私はrails4を想定しています）？
アプリ/ビュー/注文/_form.html.erb
<div class="control-group">
<div class="field">
<%= f.label :country, 'Country' %>
<%= f.country_select :country, priority: %w(US CA), prompt: 'Please select a country' %>
</div>
<div class="field">
<%= f.label :state %><br />
<%= render partial: 'subregion_select', locals: {parent_region: f.object.country} %>
</div>
</div>
app/views/orders/_subregion_select.html.erb
<div id="order_state_wrapper">
<% parent_region ||= params[:parent_region] %>
<% country = Carmen::Country.coded(parent_region) %>
<% if country.nil? %>
<em>Please select a country above</em>
<% elsif country.subregions? %>
<%= subregion_select(:order, :state, parent_region) %>
<% else %>
<%= text_field(:order, :state) %>
<% end %>
</div>
app/assets/javascripts/orders.js.coffee
# Place all the behaviors and hooks related to the matching controller here.
# All this logic will automatically be available in application.js.
# You can use CoffeeScript in this file: http://coffeescript.org/
$ ->
$('select#order_country').change (event) ->
select_wrapper = $('#order_state_wrapper')
$('select', select_wrapper).attr('disabled', true)
country = $(this).val()
url = "/orders/subregion_options?parent_region=#{country}"
select_wrapper.load(url)
config/routes.rb
get '/orders/subregion_options' => 'orders#subregion_options'
# レーキ ルート
Prefix Verb URI Pattern Controller#Action
orders_subregion_options GET /orders/subregion_options(.:format) orders#subregion_options
サブリージョン ルートを直接参照し、国を指定する場合:
http://localhost:3000/orders/subregion_options?parent_region=%22US%22
Started GET "/orders/subregion_options?parent_region=%22US%22" for 192.168.122.1 at 2013-07-08 13:20:21 -0400
Processing by OrdersController#subregion_options as HTML
Parameters: {"parent_region"=>"\"US\""}
DEPRECATION WARNING: Relation#first with finder options is deprecated. Please build a scope and then call #first on it instead. (called from service at /usr/local/rvm/rubies/ruby-2.0.0-p195/lib/ruby/2.0.0/webrick/httpserver.rb:138)
User Load (0.2ms) SELECT "users".* FROM "users" WHERE "users"."id" = 1 ORDER BY "users"."id" ASC LIMIT 1
Rendered orders/_subregion_select.html.erb (0.2ms)
Completed 200 OK in 4ms (Views: 1.3ms | ActiveRecord: 0.2ms)