本文介绍了无法建立嵌套的多态关联。您是否要建立多态的一对一关联的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我也遇到过类似的情况，即我的活动包含一个任务，其中一个任务具有一个可执行任务，而构建该任务也将构建该任务，例如：
I have had a similar situation where i had Activities which has one Task which has one taskable and building the task would also build the taskable, like so:
def new @activity = Activity.new @activity.task = @activity.build_task end现在我有包含许多TermTranslations的术语，其中的许多附件都具有可附加的附件（图像或音频），但第18行 @term = admin / term.rb的Term.new（permitted_params [：term]）我收到此错误：
Now i have Terms which have many TermTranslations which have many attachments which have an attachable (Image or Audio) but line 18 @term = Term.new(permitted_params[:term]) of admin/term.rb i get this error:
无法建立关联 attachable。您是否要建立多态的一对一关联。
Cannot build association `attachable'. Are you trying to build a polymorphic one-to-one association.
admin / term.rb
ActiveAdmin.register Term do permit_params :id, :display_name, :slug, term_translations_attributes: [:id, :slug, :title, :definition, :example, :language_id, :term_id, :_destroy, attachments_attributes: [:id, :name, :attachable_type, :attachable_id, :_destroy, attachable_attributes: [:id, :image_file, :audio_file, :_destroy]]] form partial: 'form' controller do def new @term = Term.new @term.term_translations.build.attachments.build end def create @term = Term.new(permitted_params[:term]) @term.term_translations.each do |tt| tt.attachments.each do |a| a.attachable = create_attachable(permitted_params[:term][:term_translations_attributes]) end end if @term.save redirect_to admin_term_path(@term) else render :new end end private def create_attachable(term_translations_params) raise term_translations_params.values[0].inspect attachable = term_translations_params.values[0][:attachments_attributes].values[0][:attachable_type].classify attachable.safe_constantize.new(term_translations_params.values[0][:attachable_attributes]) end end end模型
class Term < ActiveRecord::Base has_many :term_translations, dependent: :destroy has_many :activities accepts_nested_attributes_for :term_translations, allow_destroy: true end - class TermTranslation < ActiveRecord::Base belongs_to :language belongs_to :term has_many :attachments, dependent: :destroy accepts_nested_attributes_for :attachments, allow_destroy: true attr_accessor :attachable_attributes end - class Attachment < ActiveRecord::Base belongs_to :term_translation belongs_to :attachable, polymorphic: true, dependent: :destroy accepts_nested_attributes_for :attachable, allow_destroy: true end - class Image < ActiveRecord::Base has_attached_file :image_file, path: '/images/:filename' validates_attachment_content_type :image_file, content_type: /\Aimage\/.*\Z/ has_one :attachment, as: :attachable end视图
admin / terms / _form.html.erb：
<%= semantic_form_for [:admin, @term], :builder => ActiveAdmin::FormBuilder, multipart: true do |f| %> <%= f.semantic_errors *f.object.errors.keys %> <%= f.inputs 'Details' do %> <%= f.input :display_name %> <%= f.input :slug %> <% end %> <%= render partial: '/admin/term_translations/form', locals: {f: f} %> <%= f.actions %> <% end %>admin / term_translations / _form.html.erb：
<% f.has_many :term_translations, heading: 'Translations', allow_destroy: true, new_record: true, multipart: true do |t| %> <% t.input :title %> <% t.input :slug %> <% t.input :language %> <% t.has_many :attachments, heading: 'Attachments', allow_destroy: true, new_record: true, multipart: true do |a| %> <% a.input :name %> <% if a.object.attachable %> <% a.input :attachable_type, as: :string, :input_html => { readonly: true } %> <% else %> <% a.input :attachable_type, as: :select, collection: ['Image', 'Audio'] %> <% end %> <div id='attachable_partial_container'> <% if a.object.attachable.class.to_s == 'Image' %> <%= render partial: '/admin/images/form', locals: { a: a } %> <% elsif a.object.attachable.class.to_s == 'Audio' %> <%= render partial: '/admin/audios/form', locals: { a: a } %> <% end %> </div> <script type="text/javascript"> $(function () { $('#term_term_translations_attributes_NEW_TERM_TRANSLATION_RECORD_attachments_attributes_NEW_ATTACHMENT_RECORD_attachable_type_input').change(onTypeSelected); function onTypeSelected(e) { if (e.val === 'Image') $('#attachable_partial_container').replaceWith(renderImage()); else if (e.val === 'Audio') $('#attachable_partial_container').replaceWith(renderAudio()); } function renderImage() { return ( "<div id='attachable_partial_container'>" + "<%= escape_javascript render partial: '/admin/images/form', locals: {a: a} %>" + "</div" ); } function renderAudio() { return ( "<div id='attachable_partial_container'>" + "<%= escape_javascript render partial: '/admin/audios/form', locals: {a: a} %>" + "</div" ); } }); </script> <% end %> <% end %>admin / images / _form.html.erb：
<%= a.inputs for: [:attachable_attributes, a.object.attachable || Image.new], multipart: true do |i| %> <% i.input :image_file, as: :file, multipart: true %> <% end %>admin / audios / _form.html.erb：
<%= a.inputs for: [:attachable_attributes, a.object.attachable || Audio.new], multipart: true do |i| %> <% i.input :audio_file, as: :file, multipart: true %> <% end %>堆栈跟踪
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in tagged' activesupport (4.2.0) lib/active_support/tagged_logging.rb:26:in `tagged' activesupport (4.2.0) lib/active_support/tagged_logging.rb:68:in `tagged' railties (4.2.0) lib/rails/rack/logger.rb:20:in `call' actionpack (4.2.0) lib/action_dispatch/middleware/request_id.rb:21:in `call' rack (1.6.8) lib/rack/methodoverride.rb:22:in `call' rack (1.6.8) lib/rack/runtime.rb:18:in `call' activesupport (4.2.0) lib/active_support/cache/strategy/local_cache_middleware.rb:28:in `call' rack (1.6.8) lib/rack/lock.rb:17:in `call' actionpack (4.2.0) lib/action_dispatch/middleware/static.rb:113:in `call' rack (1.6.8) lib/rack/sendfile.rb:113:in `call' railties (4.2.0) lib/rails/engine.rb:518:in `call' railties (4.2.0) lib/rails/application.rb:164:in `call' rack (1.6.8) lib/rack/lock.rb:17:in `call' rack (1.6.8) lib/rack/content_length.rb:15:in `call' rack (1.6.8) lib/rack/handler/webrick.rb:88:in `service' /Users/lancecoe/.rvm/rubies/ruby-2.3.3/lib/ruby/2.3.0/webrick/httpserver.rb:140:in `service' /Users/lancecoe/.rvm/rubies/ruby-2.3.3/lib/ruby/2.3.0/webrick/httpserver.rb:96:in `run' /Users/lancecoe/.rvm/rubies/ruby-2.3.3/lib/ruby/2.3.0/webrick/server.rb:296:in `block in start_thread' Request Parameters: {"utf8"=>"✓", "authenticity_token"=>"zehGpEWIuaFoAbIcOiDiaRiP7UAZxl999YuF79fPL9yypz55Jvo/QVEi3N6idELDTElORw2OoQMu3+2+CI63Pw==", "term"=>{"display_name"=>"angle", "slug"=>"angle", "term_translations_attributes"=>{"0"=>{"title"=>"angle", "slug"=>"angle", "language_id"=>"1", "attachments_attributes"=>{"0"=>{"name"=>"sss", "attachable_type"=>"Image", "attachable_attributes"=>{"image_file"=>#<ActionDispatch::Http::UploadedFile:0x007feaadf23358 @tempfile=#<Tempfile:/var/folders/xc/wjddz4j93hl7pl9d3z6ks5340000gn/T/RackMultipart20170619-14398-1ihr5sn.png>, @original_filename="Screen Shot 2017-06-19 at 5.06.39 PM.png", @content_type="image/png", @headers="Content-Disposition: form-data; name=\"term[term_translations_attributes][0][attachments_attributes][0][attachable_attributes][image_file]\"; filename=\"Screen Shot 2017-06-19 at 5.06.39 PM.png\"\r\nContent-Type: image/png\r\n">}}}}}}, "commit"=>"Create Term"}推荐答案
只需将其添加到附件模型中
Just had to add this to the Attachment model
def build_attachable(params) self.attachable = attachable_type.constantize.new(params) end更多推荐
无法建立嵌套的多态关联。您是否要建立多态的一对一关联
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