ruby-on-rails – 未定义的方法`tripphoto_changed？’为… Carr

tripphoto.rb有一个belongs_to：trip

和我的trip.rb有一个has_many：tripphotos.此外,Carrierwave文档需要更多的东西,如上传器和我已正确设置的(它没有关联工作！).

除此之外,我有trip_uploader：tripphoto,tripphotoUploader在我的trip.rb和accepts_nested_attributes_for：tripphotos,allow_destroy：true以使我的表单正常工作：

<%= fields_for :tripphotos do |photo| %>
      Img <%= photo.file_field :filename %>
    <% end %>

尽管如此,我得到错误undefined methodtripphoto_changed？’对于#`.一个快速的谷歌没有合适的结果.有什么建议？

P.S这是我的Tripphoto表：

class Tripphoto < ActiveRecord::Base {
    :id => :integer,:filename => :string,:trip_id => :integer,:created_at => :datetime,:updated_at => :datetime
}

提前致谢,

编辑：根据要求我的代码：

Trip.rb

class Trip < ActiveRecord::Base
  attr_accessible :description,:title,:user_id,:triplocations_attributes,:photo,:category_ids,:start_city,:tripphotos,:img_url,:thumb_url,:images,:tags_attributes

  # validates :title,:length => {:minimum => 3}
  # validates :description,:presence => true
  # validates_associated :tags


  has_many :triplocations,:dependent => :destroy
  has_many :tripphotos,:dependent => :destroy

  has_and_belongs_to_many :categories
  has_and_belongs_to_many :tags


  accepts_nested_attributes_for :triplocations,allow_destroy: true
  accepts_nested_attributes_for :tripphotos,allow_destroy: true
  accepts_nested_attributes_for :categories
  accepts_nested_attributes_for :tags


  mount_uploader :tripphoto,TripphotoUploader
end

Tripphoto.rb

class Tripphoto < ActiveRecord::Base
  attr_accessible :filename,:trip_id
  belongs_to :trip
end

完整的旅行表格

<%= form_for @trip,:html => {:multipart => true} do |a| %> 
    <%= a.label :title,"Routetitel" %>
    <%= a.text_field :title %>

    <%= a.label :description,"Omschrijving" %>
    <%= a.text_area :description %>

    <%= a.label :start_city,"Stad" %>
    <%= a.text_field :start_city,:id => "cityName" %>

    <% for category in Category.find(:all) %>
        <div>
          <%= check_box_tag "trip[category_ids][]",category.id,@trip.categories.include?(category) %>
          <%= category.name %>
        </div>
    <% end %>
    <%= a.fields_for :tags do |f| %>
        <p>
            <%= f.label :title,'Steekwoorden:' %>
            <%= f.text_field :title %>
        </p> 
        <div id="inputFields"></div>

    <% end %>
    <div style="background: red;">
        <%= fields_for :tripphotos do |photo| %>
          Img <%= photo.file_field :filename %>
        <% end %>
    </div>


    <%= a.submit 'Verstuur' %>
<% end %>