fields_for 与 mongoid embeds_many 嵌套文档答案

【问题标题】：fields_for with mongoid embeds_many nested documentsfields_for 与 mongoid embeds_many 嵌套文档
【发布时间】：2012-01-16 20:55:31
【问题描述】：

尝试将此 railscast 用作指南： http://railscasts.com/episodes/197-nested-model-form-part-2?view=asciicast

并遇到此错误：

`@search[queries_attributes][new_queries][queries' is not allowed as an instance variable name

型号：

#search.rb
class Search
  include Mongoid::Document
  include Mongoid::Timestamps


  belongs_to :user
  field :name,              :type => String

  embeds_many :queries
  accepts_nested_attributes_for :queries, :reject_if => lambda { |a| a[:content].blank? }, :allow_destroy => true

#query.rb
class Query
  include Mongoid::Document

  field :columns,           :type => String
  field :types,             :type => String
  field :keywords,          :type => String

  embedded_in :search, :inverse_of => :queries 

end

搜索控制器：

def new
  @search = Search.new
  @search.queries.build
  #3.times { @search.queries.build }
end

_form.html.haml 部分：

= form_for(@search) do |f|
  = f.label 'Name this search'
  = f.text_field :name, :class => 'text_field'
  = render :partial => 'query', :collection => @search.queries, :locals => { :f => f }
  = link_to_add_fields "Add Query", f, :queries 

  .actions
    = f.submit

_query.html.haml 部分：

.fields
  = f.fields_for "queries[]", query do |q|

    = q.label 'Search Datatype'
    = q.select :types, Query::TYPES

    = q.label 'In Column'
    = q.select :columns, @search.record_columns

    = q.label 'For Keywords:'
    = q.text_field :keywords, :class => 'text_field'

    = q.hidden_field :_destroy 
    = link_to_function "remove", "remove_fields(this)"

搜索助手：

module SearchesHelper

    def link_to_add_fields(name, f, association)
      new_object = f.object.class.reflect_on_association(association).klass.new
      fields = f.fields_for(association, new_object, :child_index => "new_#{association}") do |builder|
        render(association.to_s.singularize , :f => builder)
      end
      link_to_function(name, h("add_fields(this, \"#{association}\", \"#{escape_javascript(fields)}\")"))
    end

end

javascript：

function remove_fields(link) {
        $(link).prev("input[type=hidden]").val("1");
        $(link).closest(".fields").hide();
}

function add_fields(link, association, content) {
        var new_id = new Date().getTime();
        var regexp = new RegExp("new_" + association, "g");
        $(link).parent().before(content.replace(regexp, new_id));
}

当行：

= link_to_add_fields "Add Query", f, :queries

已被注释掉，它按预期工作，但我需要能够添加额外的查询通过这个助手。为了测试多个查询，我触发了控制器中的创建 3.times

同样在错误消息中最后一个“]”被剥离..不确定我错过了什么

抱歉所有标签，但不确定问题出在哪里

【问题讨论】：

当你调用方法link_to_add_fields时你已经嵌套了fields_for调用 --> form_for -> fields_for(from function) -> fields_for(from partial)。正如泰勒已经指出的那样，可能存在命名冲突

标签： javascript mongodb ruby-on-rails-3.1 mongoid

【解决方案1】：

两个想法：

我会将 Query 类命名为其他名称，根据您指定的错误消息，它可能与 mongoid 中的某些内容冲突：

@search[queries_attributes][new_queries][queries' is not allowed as an instance variable name]

我也在谷歌上搜索你遇到的问题：

http://www.jtanium.com/2009/11/03/rails-fields_for-is-not-allowed-as-an-instance-variable-name/

某些东西在不应该出现的地方必须是 nil。

【讨论】：

【解决方案2】：

看起来这是解决办法：

= f.fields_for :queries, query do |q|

【讨论】：