问Rails 4.2.6未定义方法page_id

EN

<%= error_messages_for(@section) %>

<table summary="Section form fields">
    <tr>
        <th><%= f.label(:page_id, "Page") %></th>
        <td><%= f.select(:page_id, @pages.map {|s| [s.name, s.id]}) %></td>
    </tr>

    <tr>
        <th><%= f.label(:name) %></th>
        <td><%= f.text_field(:name) %></td>
    </tr>

    <tr>
        <th><%= f.label(:position) %></th>
        <td><%= f.select(:position, 1..@section_count) %></td>
    </tr>

    <tr>
        <th><%= f.label(:visible) %></th>
        <td><%= f.select(:visible, {"Visible" => 1, "Hidden" => 2}) %></td>
    </tr>

    <tr>
        <th><%= f.label(:content_type) %></th>
        <td><%= f.select(:content_type, ['text', 'HTML']) %></td>
    </tr>

    <tr>
        <th><%= f.label(:content) %></th>
        <td><%= f.text_area(:content, :size => '40x10') %></td>
    </tr>
</table>

class SectionsController < ApplicationController
  layout "admin"

  before_action :confirm_logged_in
  before_action :find_page

  def index
    @sections = @page.sections.sorted
    @subject = @page.subject
  end

  def show
    @section = Section.find(params[:id])
  end

  def new
    @section = Section.new({:page_id => @page.id, :name => "Default"})
    @pages = Page.order('position ASC')
    @section_count = Section.count + 1
  end

  def create
    @section = Section.new(section_params)

    if @section.save
      flash[:notice] = "Section created successfully."
      redirect_to(:action => 'index', :page_id => @page.id)
    else
      @pages = Page.order('position ASC')
      @section_count = Section.count + 1
      render('new')
    end
  end

  def 
    @section = Section.find(params[:id])
    @pages = Page.order('position ASC')
    @section_count = Section.count
  end

  def update
    @section = Section.find(params[:id])

    if @section.update_attributes(section_params)
      flash[:notice] = "Section updated successfully."
      redirect_to(:action => 'show', :id => @section.id, :page_id => @page.id)
    else
      @section = Section.find(params[:id])
      @pages = Page.order('position ASC')
      @section_count = Section.count
      render('')
    end
  end

  def delete
    @section = Section.find(params[:id])
  end

  def destroy
    section = Section.find(params[:id]).destroy
    flash[:notice] = "Section '#{section.name}' destroyed succsessfully."
    redirect_to(:action => 'index')
  end

  private
    def section_params
      params.require(:section).permit(:page_id, :name, :permalink, :position, :visible, :content_type, :content)
    end

    def find_page
      if params[:page_id]
        @page = Page.find(params[:page_id])
        @subject = @page.subject
      end
    end
end

class Section < ActiveRecord::Base
    belongs_to :page
    has_many :section_edits
    has_many :editors, :through => :section_edits, :class_name => "AdminUser"

    CONTENT_TYPES = ['text', 'HTML']

    validates_presence_of :name
    validates_length_of :name, :maximum => 255

    validates_inclusion_of :content_type, :in => CONTENT_TYPES,
    :message => "must be one of: #{CONTENT_TYPES.join(', ')}"
    validates_presence_of :content

    scope :visible, lambda { where(:visible => true) }
    scope :invisible, lambda { where(:visible => false) }
    scope :sorted, lambda { order("sections.position ASC") }
    scope :newest_first, lambda { order("sections.created_at DESC") }
end

class Page < ActiveRecord::Base
    belongs_to :subject
    has_many :sections
    has_and_belongs_to_many :editors, :class_name => "AdminUser"

    validates_presence_of :name
    validates_length_of :name, :maximum => 255

    validates_presence_of :permalink
    validates_length_of :permalink, :within => 3..255
    validates_uniqueness_of :permalink

    scope :visible, lambda { where(:visible => true) }
    scope :invisible, lambda { where(:visible => false) }
    scope :sorted, lambda { order("pages.position ASC") }
    scope :newest_first, lambda { order("pages.created_at DESC") }
end