Rails 4:未知属性: shared_attachments_attributes for accepts_nested_attributes_for

Question

模型/参与者访问。

class ParticipantAttachment < ActiveRecord::Base
  belongs_to :participant
  has_many :shared_attachments
  validates_presence_of :attachment

  accepts_nested_attributes_for :shared_attachments, reject_if: :all_blank,
           allow_destroy: true
end

模型/共享攻击。

class SharedAttachment < ActiveRecord::Base
  belongs_to :participant
  belongs_to :participant_attachment
end

shared_attachment.html.haml

    %ul
      - @participants.each do |participant|
        = hidden_field_tag 'participant_attachments[shared_attachments_attributes][][participant_attachment_id]', @attachment.id rescue nil
        %li
          %label= participant.full_name
          = check_box_tag "participant_attachments[shared_attachments_attributes][][participant_id]", participant.id, @shared_participants.include?(participant.id.to_s)

participant_attachments_controller.rb

  def create_shared_participants
    shared_participants = SharedAttachment.new(activity_params)
    shared_participants.save
  end

  def activity_params
    params.require(:participant_attachments).permit(
      :participant_id, :attachment, shared_attachments_attributes: [:participant_id, :participant_attachment_id]
    )
  end

我试图使用accespts_nested_attributes_for保存多个复选框的值。但是得到错误像未知属性: shared_attachments_attributes.any解决方案？

这是日志：

  Parameters: {"utf8"=>"✓", "authenticity_token"=>"efwsP0tQksCSQqwqoH2qJwANJ/OFChQviG+4Kz8SYgI=", "participant_attachments"=>{"shared_attachments_attributes"=>[{"participant_attachment_id"=>"14", "participant_id"=>"2"}, {"participant_attachment_id"=>"14", "participant_id"=>"4"}]}}
Completed 500 Internal Server Error in 15ms

ActiveRecord::UnknownAttributeError (unknown attribute: shared_attachments_attributes):
  app/controllers/participant/participant_attachments_controller.rb:34:in `create_shared_participants'

提前谢谢。

Answer 1

fields_for

这个问题很可能是由于在您的fields_for元素中没有正确地使用form_for助手造成的。

通常，当您在您的accepts_nested_attributes_for中设置一个model参数时，您将使用fields_for将相对数据传递给您的控制器/模型，而不是像您所拥有的那样手动设置它们：

#app/controllers/participant_attachments_controller.rb
Class ParticipantAttachmentsController < ApplicationController
   def new
      @participants = ParticipantAttachment.all
      @participant_attachment = ParticipantAttachment.new

      @participants.each do
         @participant_attachment.shared_attachments.build
      end
   end
end

#app/views/participant_attachments/new.html.erb
<%= form_for @participant_attachments do |f| %>
   <%= f.fields_for :shared_attachments do |sa| %>
        <%= sa.text_field :participant_id %>
        <%= sa.text_field :participant_attachment_id
   <% end %>
<% end %>

这将自动给出3组“嵌套”模型属性，您可以将这些属性发送到模型中。

我不确定这是否能直接解决您的问题，但我知道您应该这样做，以确保您的应用程序能够正常工作