ruby-on-rails - accepts_nested_attributes_for 和 has_many 多态

Question

我使用回形针上传附加到学生类(class)作业的多个文件，但我失败了。

型号

class StudentCourseAssignment < ActiveRecord::Base
    attr_accessible :score, :comment, :finish_status,:attachments
    accepts_nested_attributes_for :attachments
    belongs_to :assignment
    belongs_to :user
    has_many :attachments ,:as => :attachmentable,:dependent => :destroy
end

class Attachment < ActiveRecord::Base
    attr_accessible :user_upload 
    belongs_to :attachmentable , :polymorphic => true
    has_attached_file :user_upload
end

控制者

**new**

    @sca = StudentCourseAssignment.new 
    @sca.attachments.build
    @sca.attachments.build

**create**

    @sca = StudentCourseAssignment.new(params[:student_course_assignment])
    @assignment = Assignment.find(params[:assignment_id])
    @sca.user = current_user
    @sca.assignment = @assignment
    if @sca.save
        flash[:alert] = "success"
        redirect_to course_years_path
    else
        flash[:alert] = "fail"
        redirect_to course_years_path
    end

** 查看**

<%= form_for @sca, :url => assignment_student_course_assignments_path(@assignment),
:html => { :id => 'student-assignment-form', :multipart => true } do |f| %>
file:
<%= f.fields_for :attachments do |a_f| %>
<%= a_f.file_field :user_upload %>
<%= submit_tag "create" %>
<% end%>
<% end %>

错误

No association found for name `attachments'. Has it been defined yet?

如果去掉accepts_nested_attributes_for :attachments，还是错误

Attachment(#70201401779680) expected, got Array(#70201383294620)

希望得到您的帮助!谢谢!

Answer 1

改变

来自:

attr_accessible :score, :comment, :finish_status,:attachments

到:

attr_accessible :score, :comment, :finish_status,:attachments_attributes