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我正在尝试使用 Cocoon Gem 构建嵌套表单。但是我收到如下所示的错误。我在这里找到了另一个已回答的问题，即Rails Cocoon Gem: Undefined Method 'new_record?' 在与 Wicked 的 link_to_remove_association 上。但是，正如您从我的模型代码中看到的那样，唯一的答案已经被排除在外。

错误 

 ActionView::Template::Error (undefined method `new_record?' for nil:NilClass):
        1: <div class="nested-fields">
        2:      <%=f.input :name%>
        3:      <%= link_to_remove_association "remove task", f%>
        4: </div>
      app/views/templates/_room_fields.html.erb:3:in `_app_views_templates__room_fields_html_erb__1867913568926009508_70125979350780'
      app/views/templates/_form.html.erb:5:in `block (2 levels) in _app_views_templates__form_html_erb__4123974558704004784_70125994949300'
      app/views/templates/_form.html.erb:4:in `block in _app_views_templates__form_html_erb__4123974558704004784_70125994949300'
      app/views/templates/_form.html.erb:1:in `_app_views_templates__form_html_erb__4123974558704004784_70125994949300'
      app/views/templates/new.html.erb:1:in `_app_views_templates_new_html_erb___3689493092838604682_70125964273280'Models

楷模

 class Template < ActiveRecord::Base
      has_many :rooms
      accepts_nested_attributes_for :rooms, :allow_destroy => true
    end
 class Room < ActiveRecord::Base
      belongs_to :template
      has_many :items
      accepts_nested_attributes_for :items, :allow_destroy => true
    end
 class Item < ActiveRecord::Base
      belongs_to :room
    end

表单视图

<%= simple_form_for @template do |f| %>
    <%= f.input :name%>
    <div id="rooms">
        <%= simple_fields_for :rooms do |room| %>
            <%= render 'room_fields',:f => room %>
        <%end%>
        <div class="links">
            <%= link_to_add_association 'add room', f, :rooms%>
        </div>
    </div>
<%end%>

房间部分

<div class="nested-fields">
        <%=f.input :name%>
        <%= link_to_remove_association "remove task", f%>
</div>

控制器

class TemplatesController < ApplicationController
  def new
    @template = Template.new
  end

  def create
  end
end
4

2 回答 2

1

这里的错误simple_fields_for是没有链接到表单对象。所以写 

<%= f.simple_fields_for :rooms do |room| %>
于 2016-11-23T13:42:22.110 回答
-1

Cocoon is trying to execute f.object.new_record? and from the error message you are shown, it is clear that f.object is nil.

I see that the problem is in the new action. You have built a blank Template object, but there isn't any room associated with it. You have to do this - 

def new
  @template = Template.new
  @template.rooms.build
end
于 2014-12-27T06:29:32.770 回答