Rails 未定义的方法“model_name”以部分形式呈现

【问题标题】：Rails undefined method `model_name' in form partialRails 未定义的方法“model_name”以部分形式呈现
【发布时间】：2013-08-01 22:27:32
【问题描述】：

我有这个模型：

class ToType < ActiveRecord::Base
  attr_accessible :Name, :TYP_CCM, :TYP_CCM_TAX, :TYP_CDS_ID, :TYP_CTM, :TYP_CYLINDERS, :TYP_DOORS, :TYP_HP_FROM, :TYP_HP_UPTO, :TYP_ID, :TYP_KV_ABS_DES_ID, :TYP_KV_ASR_DES_ID, :TYP_KV_AXLE_DES_ID, :TYP_KV_BODY_DES_ID, :TYP_KV_BRAKE_SYST_DES_ID, :TYP_KV_BRAKE_TYPE_DES_ID, :TYP_KV_CATALYST_DES_ID, :TYP_KV_DRIVE_DES_ID, :TYP_KV_ENGINE_DES_ID, :TYP_KV_FUEL_DES_ID, :TYP_KV_FUEL_SUPPLY_DES_ID, :TYP_KV_MODEL_DES_ID, :TYP_KV_STEERING_DES_ID, :TYP_KV_STEERING_SIDE_DES_ID, :TYP_KV_TRANS_DES_ID, :TYP_KV_VOLTAGE_DES_ID, :TYP_KW_FROM, :TYP_KW_UPTO, :TYP_LA_CTM, :TYP_LITRES, :TYP_MAX_WEIGHT, :TYP_MMT_CDS_ID, :TYP_MOD_ID, :TYP_PCON_END, :TYP_PCON_START, :TYP_RT_EXISTS, :TYP_SORT, :TYP_TANK, :TYP_VALVES, :is_in_to
  set_primary_key :TYP_ID
  belongs_to :to_model
  has_many :to_articles, :foreign_key => "to_type_id", :dependent => :destroy
end

class ToArticle < ActiveRecord::Base
  attr_accessible :details, :manufacturer, :name, :oem_number, :only_with_vin, :quantity, :to_type_id
  belongs_to :to_type, :foreign_key => "TYP_ID"
  belongs_to :to_engine
end

（一些db是从大目录转换而来的，所以rails约定有些不完善）

我对 to_type 的部分展示视图：

%td
            = link_to "Подробнее", admin_catalog_to_to_article_path(c), :class=>'btn btn-primary'
            = link_to "Редактирование", edit_admin_catalog_to_to_type_path(c), :class=>'btn btn-warning'
            = link_to "Удалить", admin_catalog_to_to_type_path(c), :confirm => "!!!Тип #{c.Name} будет удалён!!!! Вы уверены?", :method => :delete, :class => "btn btn-danger"

我的显示操作对我的控制器正常工作：

class Admin::Catalog::To::ToTypesController < ApplicationController
  respond_to :html

  before_filter :auth_user

  def auth_user
    redirect_to new_admin_session_path unless admin_signed_in?
  end

  def show
    @mod_id = params[:id]
    @man = ToType.find(:all, conditions: {:TYP_MOD_ID => @mod_id}, order: "Name ASC")
    render :layout => 'admin'
  end

  def edit
    @man = ToType.find(params[:id])
    render :layout => 'admin'
  end

  def update
    @man = ToType.find(params[:id])
    if @mod.update_attributes(params[:to_type])
      redirect_to admin_catalog_to_to_type_path(@man.TYP_MOD_ID)
    else
      render :layout => 'admin'
    end
  end

  def new
    @man = ToType.new
    @mod_id = params[:mod_id]
    render :layout => 'admin'
  end

  def create
    @man = ToType.new(params[:to_type])
    @mod_id = params[:mod_id]
    @man.TYP_MOD_ID = @mod_id
    if @man.save
      redirect_to admin_catalog_to_to_type_path(@mod_id)
    else
      render :layout => 'admin'
    end
  end

  def destroy
    @man = ToType.find(params[:id])
    if @man.destroy
      redirect_to admin_catalog_to_to_type_path(@man.TYP_MOD_ID)
    else
      render :layout => 'admin'
    end
  end
end

and route:

namespace :admin do
  namespace :catalog do
      namespace :to do
        resources :to_manufacturers, 
                  :to_models, 
                  :to_types, 
                  :to_articles
      end
    end

  end

形成部分：

= form_for [:admin, :catalog, :to, @man] do |f|
  = f.label :id
...

当我尝试编辑或创建时，我得到：

undefined method `model_name' for NilClass:Class

我认为与模型的连接有问题：更新和创建。在日志中，我看到该对象是在 db 中创建的，例如，在日志中我可以看到 @man 不是空的，但我仍然得到 undefined methodmodel_name' for NilClass:Class` 。为什么？

upd：完整跟踪

        NoMethodError in Admin/catalog/to/to_types#edit

Showing /media/sf__Projects/Denis/app/views/admin/catalog/to/to_types/_edit.html.haml where line #1 raised:

undefined method `model_name' for NilClass:Class
Extracted source (around line #1):

1: = form_for [:admin, :catalog, :to, @man] do |f|
2:   = f.label :id
Trace of template inclusion: app/views/admin/catalog/to/to_types/edit.html.haml

Rails.root: /media/sf__Projects/Denis

Application Trace | Framework Trace | Full Trace
activemodel (3.2.8) lib/active_model/naming.rb:163:in `model_name_from_record_or_class'
activemodel (3.2.8) lib/active_model/naming.rb:158:in `param_key'
actionpack (3.2.8) lib/action_view/helpers/form_helper.rb:369:in `form_for'
haml (4.0.3) lib/haml/helpers/action_view_mods.rb:146:in `form_for_with_haml'
haml (4.0.3) lib/haml/helpers/action_view_xss_mods.rb:28:in `form_for_with_haml_xss'
app/views/admin/catalog/to/to_types/_edit.html.haml:1:in `_app_views_admin_catalog_to_to_types__edit_html_haml___4584370517694291299_51970960'
actionpack (3.2.8) lib/action_view/template.rb:145:in `block in render'
activesupport (3.2.8) lib/active_support/notifications.rb:125:in `instrument'
actionpack (3.2.8) lib/action_view/template.rb:143:in `render'
actionpack (3.2.8) lib/action_view/renderer/partial_renderer.rb:265:in `render_partial'
actionpack (3.2.8) lib/action_view/renderer/partial_renderer.rb:238:in `block in render'
actionpack (3.2.8) lib/action_view/renderer/abstract_renderer.rb:38:in `block in instrument'
activesupport (3.2.8) lib/active_support/notifications.rb:123:in `block in instrument'
activesupport (3.2.8) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (3.2.8) lib/active_support/notifications.rb:123:in `instrument'
actionpack (3.2.8) lib/action_view/renderer/abstract_renderer.rb:38:in `instrument'
actionpack (3.2.8) lib/action_view/renderer/partial_renderer.rb:237:in `render'
actionpack (3.2.8) lib/action_view/renderer/renderer.rb:41:in `render_partial'
actionpack (3.2.8) lib/action_view/helpers/rendering_helper.rb:27:in `render'
haml (4.0.3) lib/haml/helpers/action_view_mods.rb:10:in `block in render_with_haml'
haml (4.0.3) lib/haml/helpers.rb:89:in `non_haml'
haml (4.0.3) lib/haml/helpers/action_view_mods.rb:10:in `render_with_haml'
app/views/admin/catalog/to/to_types/edit.html.haml:7:in `_app_views_admin_catalog_to_to_types_edit_html_haml___2140731807560860717_28965400'
actionpack (3.2.8) lib/action_view/template.rb:145:in `block in render'
activesupport (3.2.8) lib/active_support/notifications.rb:125:in `instrument'
actionpack (3.2.8) lib/action_view/template.rb:143:in `render'
actionpack (3.2.8) lib/action_view/renderer/template_renderer.rb:47:in `block (2 levels) in render_template'
actionpack (3.2.8) lib/action_view/renderer/abstract_renderer.rb:38:in `block in instrument'
activesupport (3.2.8) lib/active_support/notifications.rb:123:in `block in instrument'
activesupport (3.2.8) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (3.2.8) lib/active_support/notifications.rb:123:in `instrument'
actionpack (3.2.8) lib/action_view/renderer/abstract_renderer.rb:38:in `instrument'
actionpack (3.2.8) lib/action_view/renderer/template_renderer.rb:46:in `block in render_template'
actionpack (3.2.8) lib/action_view/renderer/template_renderer.rb:54:in `render_with_layout'
actionpack (3.2.8) lib/action_view/renderer/template_renderer.rb:45:in `render_template'
actionpack (3.2.8) lib/action_view/renderer/template_renderer.rb:18:in `render'
actionpack (3.2.8) lib/action_view/renderer/renderer.rb:36:in `render_template'
actionpack (3.2.8) lib/action_view/renderer/renderer.rb:17:in `render'
actionpack (3.2.8) lib/abstract_controller/rendering.rb:110:in `_render_template'
actionpack (3.2.8) lib/action_controller/metal/streaming.rb:225:in `_render_template'
actionpack (3.2.8) lib/abstract_controller/rendering.rb:103:in `render_to_body'
actionpack (3.2.8) lib/action_controller/metal/renderers.rb:28:in `render_to_body'
actionpack (3.2.8) lib/action_controller/metal/compatibility.rb:50:in `render_to_body'
actionpack (3.2.8) lib/abstract_controller/rendering.rb:88:in `render'
actionpack (3.2.8) lib/action_controller/metal/rendering.rb:16:in `render'
actionpack (3.2.8) lib/action_controller/metal/instrumentation.rb:40:in `block (2 levels) in render'
activesupport (3.2.8) lib/active_support/core_ext/benchmark.rb:5:in `block in ms'
/home/pavel/.rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/benchmark.rb:295:in `realtime'
activesupport (3.2.8) lib/active_support/core_ext/benchmark.rb:5:in `ms'
actionpack (3.2.8) lib/action_controller/metal/instrumentation.rb:40:in `block in render'
actionpack (3.2.8) lib/action_controller/metal/instrumentation.rb:83:in `cleanup_view_runtime'
activerecord (3.2.8) lib/active_record/railties/controller_runtime.rb:24:in `cleanup_view_runtime'
actionpack (3.2.8) lib/action_controller/metal/instrumentation.rb:39:in `render'
app/controllers/admin/catalog/to/to_types_controller.rb:18:in `edit'
actionpack (3.2.8) lib/action_controller/metal/implicit_render.rb:4:in `send_action'
actionpack (3.2.8) lib/abstract_controller/base.rb:167:in `process_action'
actionpack (3.2.8) lib/action_controller/metal/rendering.rb:10:in `process_action'
actionpack (3.2.8) lib/abstract_controller/callbacks.rb:18:in `block in process_action'
activesupport (3.2.8) lib/active_support/callbacks.rb:447:in `_run__3422493215220642812__process_action__1624115620138968240__callbacks'
activesupport (3.2.8) lib/active_support/callbacks.rb:405:in `__run_callback'
activesupport (3.2.8) lib/active_support/callbacks.rb:385:in `_run_process_action_callbacks'
activesupport (3.2.8) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (3.2.8) lib/abstract_controller/callbacks.rb:17:in `process_action'
actionpack (3.2.8) lib/action_controller/metal/rescue.rb:29:in `process_action'
actionpack (3.2.8) lib/action_controller/metal/instrumentation.rb:30:in `block in process_action'
activesupport (3.2.8) lib/active_support/notifications.rb:123:in `block in instrument'
activesupport (3.2.8) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (3.2.8) lib/active_support/notifications.rb:123:in `instrument'
actionpack (3.2.8) lib/action_controller/metal/instrumentation.rb:29:in `process_action'
actionpack (3.2.8) lib/action_controller/metal/params_wrapper.rb:207:in `process_action'
activerecord (3.2.8) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
actionpack (3.2.8) lib/abstract_controller/base.rb:121:in `process'
actionpack (3.2.8) lib/abstract_controller/rendering.rb:45:in `process'
actionpack (3.2.8) lib/action_controller/metal.rb:203:in `dispatch'
actionpack (3.2.8) lib/action_controller/metal/rack_delegation.rb:14:in `dispatch'
actionpack (3.2.8) lib/action_controller/metal.rb:246:in `block in action'
actionpack (3.2.8) lib/action_dispatch/routing/route_set.rb:73:in `call'
actionpack (3.2.8) lib/action_dispatch/routing/route_set.rb:73:in `dispatch'
actionpack (3.2.8) lib/action_dispatch/routing/route_set.rb:36:in `call'
journey (1.0.4) lib/journey/router.rb:68:in `block in call'
journey (1.0.4) lib/journey/router.rb:56:in `each'
journey (1.0.4) lib/journey/router.rb:56:in `call'
actionpack (3.2.8) lib/action_dispatch/routing/route_set.rb:600:in `call'
warden (1.2.1) lib/warden/manager.rb:35:in `block in call'
warden (1.2.1) lib/warden/manager.rb:34:in `catch'
warden (1.2.1) lib/warden/manager.rb:34:in `call'
actionpack (3.2.8) lib/action_dispatch/middleware/best_standards_support.rb:17:in `call'
rack (1.4.5) lib/rack/etag.rb:23:in `call'
rack (1.4.5) lib/rack/conditionalget.rb:25:in `call'
actionpack (3.2.8) lib/action_dispatch/middleware/head.rb:14:in `call'
actionpack (3.2.8) lib/action_dispatch/middleware/params_parser.rb:21:in `call'
actionpack (3.2.8) lib/action_dispatch/middleware/flash.rb:242:in `call'
rack (1.4.5) lib/rack/session/abstract/id.rb:210:in `context'
rack (1.4.5) lib/rack/session/abstract/id.rb:205:in `call'
actionpack (3.2.8) lib/action_dispatch/middleware/cookies.rb:339:in `call'
activerecord (3.2.8) lib/active_record/query_cache.rb:64:in `call'
activerecord (3.2.8) lib/active_record/connection_adapters/abstract/connection_pool.rb:473:in `call'
actionpack (3.2.8) lib/action_dispatch/middleware/callbacks.rb:28:in `block in call'
activesupport (3.2.8) lib/active_support/callbacks.rb:405:in `_run__2440713806940417433__call__2360308109704352565__callbacks'
activesupport (3.2.8) lib/active_support/callbacks.rb:405:in `__run_callback'
activesupport (3.2.8) lib/active_support/callbacks.rb:385:in `_run_call_callbacks'
activesupport (3.2.8) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (3.2.8) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
actionpack (3.2.8) lib/action_dispatch/middleware/reloader.rb:65:in `call'
actionpack (3.2.8) lib/action_dispatch/middleware/remote_ip.rb:31:in `call'
actionpack (3.2.8) lib/action_dispatch/middleware/debug_exceptions.rb:16:in `call'
actionpack (3.2.8) lib/action_dispatch/middleware/show_exceptions.rb:56:in `call'
railties (3.2.8) lib/rails/rack/logger.rb:26:in `call_app'
railties (3.2.8) lib/rails/rack/logger.rb:16:in `call'
actionpack (3.2.8) lib/action_dispatch/middleware/request_id.rb:22:in `call'
rack (1.4.5) lib/rack/methodoverride.rb:21:in `call'
rack (1.4.5) lib/rack/runtime.rb:17:in `call'
activesupport (3.2.8) lib/active_support/cache/strategy/local_cache.rb:72:in `call'
rack (1.4.5) lib/rack/lock.rb:15:in `call'
actionpack (3.2.8) lib/action_dispatch/middleware/static.rb:62:in `call'
railties (3.2.8) lib/rails/engine.rb:479:in `call'
railties (3.2.8) lib/rails/application.rb:223:in `call'
rack (1.4.5) lib/rack/content_length.rb:14:in `call'
railties (3.2.8) lib/rails/rack/log_tailer.rb:17:in `call'
rack (1.4.5) lib/rack/handler/webrick.rb:59:in `service'
/home/pavel/.rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/webrick/httpserver.rb:138:in `service'
/home/pavel/.rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/webrick/httpserver.rb:94:in `run'
/home/pavel/.rvm/rubies/ruby-1.9.3-p429/lib/ruby/1.9.1/webrick/server.rb:191:in `block in start_thread'
Request

Parameters:

{"id"=>"28752"}
Show session dump

Show env dump

Response

Headers:

None

【问题讨论】：

  • 我也尝试重命名为 to_engines：没有帮助...我不明白为什么？ (
  • 错误表明当你期待一个对象时你有 nil 。在编辑代码中，您不检查 find() 是否返回记录。如果您传入数据库中不存在的 id 会发生什么？
  • @Fred 但我从 db 中看到它选择数据
  • @Fred 你怎么看？
  • 鉴于您在这里的内容，嵌套资源看起来很奇怪。我不明白为什么您在 admin 下有多个 :catalogs 命名空间的声明（以及 :to 的多个声明，等等）。也许这是令人困惑的轨道？只是一个建议。

标签： ruby-on-rails ruby activerecord routes partial


【解决方案1】：

看起来太简单了，但是@typ 是在哪里定义的？你有 @typ 部分但 @man 在控制器中。

【讨论】：

  • 对不起，这是其他部分...新还有其他对象，什么时候有一个相同的对象我得到错误..我编辑了问题
  • 那么你现在怎么看？
  • 尝试使用form_for [:admin, :catalog, :to, ToType.new] 测试它并显示输出。
  • 抱歉，忘记了命名空间，请尝试：Admin::Catalog::To::ToType.new 而不是 ToType.new。
  • pastebin.com/ziUn1Zj4 我也试试 = form_for [:admin, :catalog, :to, Admin::Catalog::To::ToType.new] 做 |f|
【解决方案2】：

你的表单中有这个form_for [:admin, :catalog, :to, @typ]，但你没有对象@typ - 你有@man

【讨论】：

  • 对不起，这是其他部分...新还有其他对象，什么时候有一个相同的对象我得到错误..我编辑了问题
  • 现在什么是完整的错误信息？你仍然有@typ在那里
  • @是的，我更新了代码，忘记了这个名字（我改变了代码，忘记在这里更新），问题不在那个
  • 现在看，我尝试了一点重命名，所以这有点问题，但是你可以看到使用 normall 名称都是一样的
  • 当用于表单的对象为 nil 时出现此错误。所以请检查一下你的表单会出现什么 - 我看到了控制器代码，但是......并尝试制作form_for @man, url: [:admin, :catalog, :to, @man] - 也许不会有错误
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