accept nested attributes not working

I'm trying to create a nested form but I'm missing something as keep getting an error.

--configuration model

class Configuration < ActiveRecord::Base
  has_many :configoptions
  accepts_nested_attributes_for :configoptions
end

--show configuration view

开发者_如何学Python<%= form_for @config do |f| %>
  <%= f.fields_for :configoptions do |fp| %>
    <p>
      <%= fp.label :name %>
      <%= fp.text_field :name %>
    </p>
  <% end %>    
  <%= f.submit %>
<% end %>

According to some online guides i've found this should work. but I keep getting an error:

undefined method `configuration_path' for #<#<Class:0x2549dac>:0x2548f88>

Does anyone know a way to make this work?

Thanks a lot!

---

It seems your routes are configured incorrectly. The following line:

<%= form_for @config do |f| %>

creates a form tag to post your new/updated object to. In this case, it would look for configuration_path as the default path for a new object form. Use rake routes to see if there is a listing similar to this

configurations GET    /configurations(.:format)          {:action=>"index", :controller=>"configurations"}
               POST   /configurations(.:format)          {:action=>"create", :controller=>"configurations"}

or look for resources :configurations in your config/routes.rb. (If not, add resource :configurations). If you get confused by routing, check out the corresponding Rails Guide: http://guides.rubyonrails.org/routing.html

Alternatively, you can specify a different URL to post the action to, by passing the :url argument to your form helper:

<%= form_for @config, :url => some_other_path do |f| %>