Ruby on Rails未定義的方法`discuss_path' - 嵌套的資源，一對多的關係

Question

這個問題似乎很簡單，但我似乎無法解決它。我一定會錯過一些明顯的東西，但是真的很感謝任何幫助！

undefined method `discussions_path' for #<#<Class:0x000001032e90d8>:0x000001030f1168> 

路線文件：

resources :forums do 
    resources :discussions 
end 

討論/ _form.html.erb文件：

<%= form_for [@forum, @discussion] do |f| %> 
<%= f.error_messages %> 
<p> 
    <%= f.label :name %><br /> 
    <%= f.text_field :name %> 
</p> 
<p><%= f.submit "Submit" %></p> 
<% end %> 

討論控制器新的動作：

出現

錯誤消息

def new 
    @forum = Forum.find_by_permalink(params[:id]) 
    @discussion = Discussion.new 
end 

這是完全錯誤，現在我得到（在終端中）：

Started GET "/forums/general-chat/discussions/new" for 127.0.0.1 at 2012-04-14 18:35:28 +0100 
Processing by DiscussionsController#new as HTML 
Parameters: {"forum_id"=>"general-chat"} 
Forum Load (1.6ms) SELECT "forums".* FROM "forums" WHERE "forums"."permalink" IS NULL LIMIT 1 
Rendered layouts/_content_full_start.html.erb (0.0ms) 
Rendered discussions/_form.html.erb (574.4ms) 
Rendered discussions/new.html.erb within layouts/application (575.9ms) 
Completed 500 Internal Server Error in 581ms 

Answer 1

對於需要在傳遞一個數組form_for與論壇和討論，例如嵌套資源設置@forum在你的控制器，然後在視圖中使用：

<%= form_for [@forum, @discussion] do |f| %> 

從rails docs：

If your resource has associations defined, for example, you want to add comments 
to the document given that the routes are set correctly: 
<%= form_for([@document, @comment]) do |f| %> 
... 
<% end %> 
Where @document = Document.find(params[:id]) and @comment = Comment.new.