Question

I have a error with page updating

ActiveRecord::AssociationTypeMismatch in Admin::PagesController#update
Page(#64407864) expected, got String(#17069256)
app/controllers/admin/pages_controller.rb:36:in `update’

line 36 of Admin::PagesController update

   if @page.update_attributes(params[:page])

page.rb

class Page < ActiveRecord::Base

  has_and_belongs_to_many :related, :class_name => "Page", :join_table => "pages_related", :foreign_key => "page_id", :association_foreign_key => "related_id"

end

_form.html.erb

    <%= f.select :related, Page.all.delete_if {|p| p.id == f.object.id}.collect {|p| [p.title, p.id]}, { :include_blank => true }, {:multiple => "multiple"} %>

up:

---

thanks, its working, but now Ive got the error with new Page creating

Called id for nil, which would
mistakenly be 4 — if you really
wanted the id of nil, use object_id

Extracted source (around line #70):

70: <%= f.select :related_ids,
Page.all.delete_if {|p| p.id ==
f.object.id}.collect {|p| [p.title,
p.id]}, { :include_blank => true },
{:multiple => “multiple”, :class =>
“select_multiple”} %>

Answer 1

Your select field should be called related_ids, since it will be passing back the IDs for the selected objects, not the actual objects themselves.