# Render partials with nested attributes in another model **URL:** \ **Category:** Rails\ **Created:** [October 14, 2009, 4:33pm UTC](https://www.ruby-forum.com/t/render-partials-with-nested-attributes-in-another-model/177294 "2009-10-14T16:33:26Z")\ **Posts on this page:** 1\ **Page:** 1
**Author:** ![Ryan\_Tinsley](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/aeb1de/32.png) [@Ryan\_Tinsley](https://www.ruby-forum.com/u/Ryan_Tinsley)\ **Post date:** [October 14, 2009, 4:33pm UTC](https://www.ruby-forum.com/t/render-partials-with-nested-attributes-in-another-model/177294/1 "2009-10-14T16:33:26Z")
Hi everyone, My previous question was posted here[http://groups.google.com/group/rubyonrails-talk/browse\_thread/thread/dddaeb075789d4b5](http://groups.google.com/group/rubyonrails-talk/browse_thread/thread/dddaeb075789d4b5). I’m starting a new topic as the problems have shifted. I have a rails application that models a house. There is a house model that has\_many rooms. A room has a house\_id and a name. I’ve also used the complex-form-examples to give room nested attributes of lights and small\_appliances. complex-form-examples uses RJS and partials to accomplish this. There is a controller called calculator that is what users will use to access the application. When the submit button on calculator is pressed, it saves house information and redirects to an add\_rooms page (located in app/views/calculator/add\_rooms.html.erb) where the user can add rooms to the house. The add\_rooms page uses a partial from app/views/rooms/\_room\_form.html.erb. I can get this page to display by removing the add\_child\_link links. If I don’t remove them, I get this error: ``` Showing app/views/rooms/_room_form.html.erb where line #13 raised: undefined method `reflect_on_association' for NilClass:Class ``` With add\_child\_link gone the page renders. However, when I click submit I get a new error message: ``` ActiveRecord::AssociationTypeMismatch in ``` CalculatorController#add\_room ``` SmallAppliance(#49096610) expected, got Array(#1560620) RAILS_ROOT: C:/Users/ryan/Downloads/react Application Trace | Framework Trace | Full Trace C:/InstantRails/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/associations/association_proxy.rb:263:in ``` `raise_on_type_mismatch' C:/InstantRails/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/associations/association_collection.rb:320:in `replace’ C:/InstantRails/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active\_record/associations/association\_collection.rb:320:in `each' C:/InstantRails/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/associations/association_collection.rb:320:in `replace’ C:/InstantRails/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active\_record/associations.rb:1322:in `small_appliances=' C:/InstantRails/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/base.rb:2744:in `send’ C:/InstantRails/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active\_record/base.rb:2744:in `attributes=' C:/InstantRails/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/base.rb:2740:in `each’ C:/InstantRails/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active\_record/base.rb:2740:in `attributes=' C:/InstantRails/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.4/lib/active_record/base.rb:2438:in `initialize’ C:/Users/ryan/Downloads/react/app/controllers/calculator\_controller.rb:31:in `new' C:/Users/ryan/Downloads/react/app/controllers/calculator_controller.rb:31:in `add\_room’ If I remove the small\_application part, the same thing happens for light. I think it has something to do with accepts\_nested\_attributes\_for in the room model. I need to get this page working so that rooms can be added to a house without using the scaffold built pages. Users won’t have access to those. I also need the house id to be saved as house\_id in the rooms table. Here is the code: _app/models/room.rb_ ``` class Room < ActiveRecord::Base belongs_to :house has_many :lights, :dependent => :destroy has_many :small_appliances, :dependent => :destroy validates_presence_of :name accepts_nested_attributes_for :lights, :reject_if => lambda { ``` |a| a.values.all?(&:blank?) }, :allow\_destroy =\> true accepts\_nested\_attributes\_for :small\_appliances, :reject\_if =\> lambda { |a| a.values.all?(&:blank?) }, :allow\_destroy =\> true end _app/models/house.rb_ ``` class House < ActiveRecord::Base has_many :rooms # validation code not included def add_room(room) rooms << room end end ``` _app/controllers/calculator\_controller.rb_ ``` class CalculatorController < ApplicationController def index end # save_house is called when submit is # pressed in app/views/calculator/index.html.erb def save_house @house = House.new(params[:house]) respond_to do |format| if @house.save format.html { render :action => 'add_rooms', :id => @house } format.xml { render :xml => @house, :status => :created, ``` :location =\> @house } else format.html { render :action =\> ‘index’ } format.xml { render :xml =\> @house.errors, :status =\> :unprocessable\_entity } end end end ``` def add_rooms @house = House.find(params[:id]) @rooms = Room.find_by_house_id(@house.id) rescue ActiveRecord::RecordNotFound logger.error("Attempt to access invalid house #{params[:id]}") flash[:notice] = "You must create a house before adding rooms" redirect_to :action => 'index' end def add_room @house = House.find(params[:id]) @room = Room.new(params[:room]) respond_to do |format| if @room.save @house.add_room(@room) @house.save flash[:notice] = "Room \"#removed_email_address@domain.invalid}\" was successfully ``` added." format.html { render :action =\> ‘add\_rooms’ } format.xml { render :xml =\> @room, :status =\> :created, :location =\> @room } else format.html { render :action =\> ‘add\_rooms’ } format.xml { render :xml =\> @room.errors, :status =\> :unprocessable\_entity } end end rescue ActiveRecord::RecordNotFound logger.error(“Attempt to access invalid house #{params[:id]}”) flash[:notice] = “You must create a house before adding a room” redirect\_to :action =\> ‘index’ end ``` def report flash[:notice] = nil @house = House.find(params[:id]) @rooms = Room.find_by_house_id(@house.id) rescue ActiveRecord::RecordNotFound logger.error("Attempt to access invalid house #{params[:id]}") flash[:notice] = "You must create a house before generating a ``` report" redirect\_to :action =\> ‘index’ end ``` end ``` _app/views/calculator/add\_rooms.html.erb_ <div id=“addRooms”> <p>House id is <%= @house.id %></p> <h3>Your rooms:</h3> <% if @house.rooms %> <ul> <% for room in @house.rooms %> <li> <%= h room.name%> has <%= h room.number\_of\_bulbs %> <%= h room.wattage\_of\_bulbs %> watt bulbs, in use for <%= h room.usage\_hours %> hours per day. </li> <% end %> </ul> <% else %> <p>You have not added any rooms yet</p> <% end %> <%= render :partial => ‘rooms/room\_form’ %> <br /> <%= button\_to “Continue to report”, :action => “report”, :id => @house %> </div> _app/views/rooms/\_room\_form.html.erb_ ``` &lt;% form_for :room, :url =&gt; { :action =&gt; ``` :add\_room, :id => @house } do |form| %> <%= form.error\_messages %> <p> <%= form.label :name %><br /> <%= form.text\_field :name %> </p> ``` &lt;h3&gt;Lights&lt;/h3&gt; &lt;% form.fields_for :lights do |light_form| %&gt; &lt;%= render :partial =&gt; 'rooms/light', :locals ``` => { :form => light\_form } %> <% end %> <p class=“addLink”><%= add\_child\_link “[+] Add new light”, form, :lights %></p> ``` &lt;h3&gt;Small Appliances&lt;/h3&gt; &lt;% form.fields_for :small_appliances do |sm_appl_form| ``` %> <%= render :partial => ‘rooms/small\_appliance’, :locals => { :form => sm\_appl\_form } %> <% end %> <p class=“addLink”><%= add\_child\_link “[+] Add new small appliance”, form, :small\_appliances %></p> ``` &lt;p&gt;&lt;%= form.submit "Submit" ``` %></p> <% end %> _application\_helper.rb_ ``` module ApplicationHelper def remove_child_link(name, form) form.hidden_field(:_delete) + link_to_function(name, ``` “remove\_fields(this)”) end ``` def add_child_link(name, form, method) fields = new_child_fields(form, method) link_to_function(name, h("insert_fields(this, \"#{method}\", ``` "#{escape\_javascript(fields)}")")) end ``` def new_child_fields(form_builder, method, options = {}) options[:object] ||= ``` form\_builder.object.class.reflect\_on\_association(method).klass.new options[:partial] ||= method.to\_s.singularize options[:form\_builder\_local] ||= :form form\_builder.fields\_for(method, options[:object], :child\_index =\> “new\_#{method}”) do |form| render(:partial =\> options[:partial], :locals =\> { options[:form\_builder\_local] =\> form }) end end end _public/javascripts/application.js_ ``` function insert_fields(link, method, content) { var new_id = new Date().getTime(); var regexp = new RegExp("new_" + method, "g") $(link).up().insert({ before: content.replace(regexp, new_id) }); } function remove_fields(link) { var hidden_field = $(link).previous("input[type=hidden]"); if (hidden_field) { hidden_field.value = '1'; } $(link).up(".fields").hide(); } ``` Thanks, Ryan