Ruby on rails 如何使用will_paginate和Rails中的嵌套资源？

我是Rails新手，在让will_paginate使用嵌套资源时遇到了很大的困难

我有两种型号，对账单和发票。will_paginate正在处理对账单，但我无法处理发票。我知道我在做一些傻事，但我想不出来，我在谷歌上找到的例子对我来说也不管用

statement.rb
class Statement < ActiveRecord::Base
  has_many :invoices

  def self.search(search, page)
    paginate :per_page => 19, :page => page,
      :conditions => ['company like ?', "%#{search}%"],
      :order => 'date_due DESC, company, supplier'
  end
end

statements_controller.rb  <irrelevant code clipped for readability>
def index #taken from the RAILSCAST 51, will_paginate podcast
  @statements = Statement.search(params[:search], params[:page])
end

I call this in the view like so, and it works:
  <%= will_paginate @statements %>

statement.rb
class语句19页，：每页=>19页，
：conditions=>['companylike'，“%#{search}%”，
：订单=>“日期\到期说明、公司、供应商”
结束
结束
语句\u controller.rb
def索引取自RAILSCAST 51，将用于播客
@语句=语句.search（参数[：search]，参数[：page]）
结束
我在视图中这样称呼它，它是有效的：

但我不知道如何让它用于发票：

invoice.rb
class Invoice < ActiveRecord::Base
  belongs_to :statement

   def self.search(search, page)
     paginate :per_page => 19, :page => page,
       :conditions => ['company like ?', "%#{search}%"],
       :order => 'employee'
  end
end

invoices_controller.rb
class InvoicesController < ApplicationController

  before_filter :find_statement


  #TODO I can't get will_paginate to work w a nested resource
  def index #taken from the RAILSCAST 51, will_paginate podcast
        @invoices = Invoice.search(params[:search], params[:page])
  end

 def find_statement
    @statement_id = params[:statement_id]
    return(redirect_to(statements_url)) unless @statement_id
    @statement = Statement.find(@statement_id)
  end
end

invoice.rb
类发票19页，：每页=>19页，
：conditions=>['companylike'，“%#{search}%”，
：order=>employee'
结束
结束
发票控制器.rb
类InvoicesController

我试着这样称呼它：

当我处理这个问题时，最常见的错误消息是： “@statements变量似乎为空。您是否忘记为will_paginate传递集合对象？”

我不知道问题是什么，也不知道如何解决。谢谢你的帮助和指导

已解决-

我将发票分页移动到报表的控制器中，如下所示：

def show
  @statement = Statement.find(params[:id])

  #TODO move the :per_page stuff out to a constant
  @invoices = @statement.invoices.paginate :per_page => 10,
    :page => params[:page],
    :order => 'created_at DESC'


 respond_to do |format|
    format.html # show.html.erb
    format.xml  { render :xml => @statement }
 end
end

并在视图中这样调用它（为可读性而修剪的代码>

  <div id="pagination">
  <%= will_paginate @invoices %>
  </div>
  <table>
  <%# @statement.invoices.each do |invoice| -
  shows all invoices with no pagination,
  use @invoices instead%>
  <%
  @invoices.each do |invoice|
  %>