问题
I have a rails application that models a house. There is a house model that has many parameters and it has_many rooms. A room has a house_id and a name. I've also used http://github.com/ryanb/complex-form-examples to allow many lights and small_appliances to be added to room. complex-form-example 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 redirects to an add_rooms page (located in app/views/calculator/add_rooms.html.erb) page 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 haven't been able to get this to display, as rails is always looking for things in the app/views/calculator folder.
How can I get this to display? Note also that I need to save the house's id when saving the room.
Here is all of the relevant code (I hope):
Update
If I comment out the two add_child_link. 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've added the code below. I've also added the house.rb code too.
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
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 \"#...@room.name}\" 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
<% form_for :room, :url => { :action => :add_room, :id => @house } do |form| %>
<%= form.error_messages %>
<p>
<%= form.label :name %><br />
<%= form.text_field :name %>
</p>
<h3>Lights</h3>
<% form.fields_for :lights do |light_form| %>
<%= render :partial => 'rooms/light', :locals => { :form => light_form } %>
<% end %>
<p class="addLink"><%= add_child_link "[+] Add new light", form, :lights %></p>
<h3>Small Appliances</h3>
<% 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>
<p><%= 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
Thanks,
Ryan
回答1:
Very strange — if you write <%= render :partial => 'room_form' %> than rails will assume that it is app/views/calculator/_room_form.html.erb, but in case of <%= render :partial => 'rooms/room_form' %> it will assume that it is app/views/rooms/_room_form.html.erb
Watch your log — there you will see which partials were rendered
回答2:
I know this question is old but I ran into the same problem and managed to solve it.
To be specific I too was following ryan bates complex forms examples.
My form was not rendering with the same error:
undefined method `reflect_on_association' for NilClass:Class
I commented out the add_child_link helper and the form rendered but upon submission I got:
ChildModel expected, got Array
After much headscratching I made one simple change that fixed everything:
-- form_for :project
++ form_for @project
That's right, just switching the symbol for an instance variable made it all work.
Hope this helps anyone else who gets stuck
回答3:
The issue is that you don't have a room object defined when you're trying to add a child link.
render :partial => 'rooms/room_form', :object => Room.new
来源：https://stackoverflow.com/questions/1556944/render-partial-from-another-model