Rails cocoon-gem双嵌套表单“未定义方法”

我在我的rails应用程序中使用cocoon gem并试图双重嵌套表单。

第一个“link_to_add_association”添加了valve_fields partial，其中包含另一个“link_to_add_association”，它给出了这个错误：

ActionView::Template::Error (undefined method `fetch_value' for nil:NilClass): 21: .line_items 22: =f.simple_fields_for :line_items do |line_item| 23: =render 'line_item_fields', :f => line_item 24: //error line// =link_to_add_association "add line", f, :line_items 

我没有为第一个链接做任何不同的事情而不是第二个链接，但由于某种原因它不起作用

 //Rfq controller def rfq_params params.require(:rfq).permit( :quote_number,:rep_id, :owner, :customer_id, :customer_name, :end_user_list, :application_list, :due, :ship_date, :is_budgetary, :notes, :mandatory_due_date, valves_attributes: [:id, :_destroy, :productline, :discwedge, :valvetype, :valveends, :valvematerial, :valveconfig, :valvenotes, line_items_attributes: [ :tag, :qty, :size, :class, :operator, :trim, :_destroy ] ]) end //form partial: .valves =f.fields_for :valves do |valve| =render 'valve_fields', :f => valve =link_to_add_association 'add valve', f, :valves, "data-association-insertion-traversal" => "next" //valve partial .line_items =f.simple_fields_for :line_items do |line_item| =render 'line_item_fields', :f => line_item =link_to_add_association "add line", f, :line_items 

Answer 1

根据你的rfq_params方法，你在valve_attributes中有valve_attributes 。 这意味着line_items nested在valve内部，所以在你的表单中你应该改变这一行f.simple_fields_for :line_items do |line_item| to valve.simple_fields_for :line_items do |line_item| 。