ruby-on-rails – 是否可以为简单类创建表单

发布时间：2020-12-17 04:14:33 所属栏目：百科来源：网络整理

导读：我只想拥有编辑类属性的能力,而不是ActiveRecord类的继承者. 这是我的类/app/model/entry.rb： class Entry attr_accessor :title,:bodyend 这是一个控制器： class DiaryController ApplicationController def new @entry = Entry.new endend 这是一个观点

我只想拥有编辑类属性的能力,而不是ActiveRecord类的继承者.

这是我的类/app/model/entry.rb：

class Entry
  attr_accessor :title,:body
end

这是一个控制器：

class DiaryController < ApplicationController
  def new
    @entry = Entry.new
  end
end

这是一个观点：

<%= form_for(@entry) do |f| %>
<%= f.text_field :title %> <br />
<%= f.text_area :body %> <br />
<% end %>

我在打开表单时收到错误消息：

undefined method `model_name’ for Entry:Class

这是完整的堆栈：

Extracted source (around line #1):

1: <%= form_for(@entry) do |f| %>
2: <%= f.text_field :title %> <br />
3: <%= f.text_area :body %> <br />
4: <% end %>


Full trace:

activemodel (3.0.6) lib/active_model/naming.rb:95:in `model_name_from_record_or_class'
activemodel (3.0.6) lib/active_model/naming.rb:82:in `singular'
actionpack (3.0.6) lib/action_view/helpers/form_helper.rb:312:in `form_for'
app/views/diary/new.html.erb:1:in `_app_views_diary_new_html_erb___902027577_26033568_187052521'
actionpack (3.0.6) lib/action_view/template.rb:135:in `block in render'
activesupport (3.0.6) lib/active_support/notifications.rb:54:in `instrument'
actionpack (3.0.6) lib/action_view/template.rb:127:in `render'
actionpack (3.0.6) lib/action_view/render/rendering.rb:59:in `block in _render_template'
activesupport (3.0.6) lib/active_support/notifications.rb:52:in `block in instrument'
activesupport (3.0.6) lib/active_support/notifications/instrumenter.rb:21:in `instrument'
activesupport (3.0.6) lib/active_support/notifications.rb:52:in `instrument'
actionpack (3.0.6) lib/action_view/render/rendering.rb:56:in `_render_template'
actionpack (3.0.6) lib/action_view/render/rendering.rb:26:in `render'
actionpack (3.0.6) lib/abstract_controller/rendering.rb:115:in `_render_template'
actionpack (3.0.6) lib/abstract_controller/rendering.rb:109:in `render_to_body'
actionpack (3.0.6) lib/action_controller/metal/renderers.rb:47:in `render_to_body'
actionpack (3.0.6) lib/action_controller/metal/compatibility.rb:55:in `render_to_body'
actionpack (3.0.6) lib/abstract_controller/rendering.rb:102:in `render_to_string'
actionpack (3.0.6) lib/abstract_controller/rendering.rb:93:in `render'
actionpack (3.0.6) lib/action_controller/metal/rendering.rb:17:in `render'
actionpack (3.0.6) lib/action_controller/metal/instrumentation.rb:40:in `block (2 levels) in render'
activesupport (3.0.6) lib/active_support/core_ext/benchmark.rb:5:in `block in ms'
c:/Ruby192/lib/ruby/1.9.1/benchmark.rb:309:in `realtime'
activesupport (3.0.6) lib/active_support/core_ext/benchmark.rb:5:in `ms'
actionpack (3.0.6) lib/action_controller/metal/instrumentation.rb:40:in `block in render'
actionpack (3.0.6) lib/action_controller/metal/instrumentation.rb:78:in `cleanup_view_runtime'
activerecord (3.0.6) lib/active_record/railties/controller_runtime.rb:15:in `cleanup_view_runtime'
actionpack (3.0.6) lib/action_controller/metal/instrumentation.rb:39:in `render'
actionpack (3.0.6) lib/action_controller/metal/implicit_render.rb:10:in `default_render'
actionpack (3.0.6) lib/action_controller/metal/implicit_render.rb:5:in `send_action'
actionpack (3.0.6) lib/abstract_controller/base.rb:150:in `process_action'
actionpack (3.0.6) lib/action_controller/metal/rendering.rb:11:in `process_action'
actionpack (3.0.6) lib/abstract_controller/callbacks.rb:18:in `block in process_action'
activesupport (3.0.6) lib/active_support/callbacks.rb:436:in `_run__776311234__process_action__123531476__callbacks'
activesupport (3.0.6) lib/active_support/callbacks.rb:410:in `_run_process_action_callbacks'
activesupport (3.0.6) lib/active_support/callbacks.rb:94:in `run_callbacks'
actionpack (3.0.6) lib/abstract_controller/callbacks.rb:17:in `process_action'
actionpack (3.0.6) lib/action_controller/metal/instrumentation.rb:30:in `block in process_action'
activesupport (3.0.6) lib/active_support/notifications.rb:52:in `block in instrument'
activesupport (3.0.6) lib/active_support/notifications/instrumenter.rb:21:in `instrument'
activesupport (3.0.6) lib/active_support/notifications.rb:52:in `instrument'
actionpack (3.0.6) lib/action_controller/metal/instrumentation.rb:29:in `process_action'
actionpack (3.0.6) lib/action_controller/metal/rescue.rb:17:in `process_action'
actionpack (3.0.6) lib/abstract_controller/base.rb:119:in `process'
actionpack (3.0.6) lib/abstract_controller/rendering.rb:41:in `process'
actionpack (3.0.6) lib/action_controller/metal.rb:138:in `dispatch'
actionpack (3.0.6) lib/action_controller/metal/rack_delegation.rb:14:in `dispatch'
actionpack (3.0.6) lib/action_controller/metal.rb:178:in `block in action'
actionpack (3.0.6) lib/action_dispatch/routing/route_set.rb:62:in `call'
actionpack (3.0.6) lib/action_dispatch/routing/route_set.rb:62:in `dispatch'
actionpack (3.0.6) lib/action_dispatch/routing/route_set.rb:27:in `call'
rack-mount (0.6.14) lib/rack/mount/route_set.rb:148:in `block in call'
rack-mount (0.6.14) lib/rack/mount/code_generation.rb:93:in `block in recognize'
rack-mount (0.6.14) lib/rack/mount/code_generation.rb:68:in `optimized_each'
rack-mount (0.6.14) lib/rack/mount/code_generation.rb:92:in `recognize'
rack-mount (0.6.14) lib/rack/mount/route_set.rb:139:in `call'
actionpack (3.0.6) lib/action_dispatch/routing/route_set.rb:493:in `call'
actionpack (3.0.6) lib/action_dispatch/middleware/best_standards_support.rb:17:in `call'
actionpack (3.0.6) lib/action_dispatch/middleware/head.rb:14:in `call'
rack (1.2.2) lib/rack/methodoverride.rb:24:in `call'
actionpack (3.0.6) lib/action_dispatch/middleware/params_parser.rb:21:in `call'
actionpack (3.0.6) lib/action_dispatch/middleware/flash.rb:182:in `call'
actionpack (3.0.6) lib/action_dispatch/middleware/session/abstract_store.rb:149:in `call'
actionpack (3.0.6) lib/action_dispatch/middleware/cookies.rb:302:in `call'
activerecord (3.0.6) lib/active_record/query_cache.rb:32:in `block in call'
activerecord (3.0.6) lib/active_record/connection_adapters/abstract/query_cache.rb:28:in `cache'
activerecord (3.0.6) lib/active_record/query_cache.rb:12:in `cache'
activerecord (3.0.6) lib/active_record/query_cache.rb:31:in `call'
activerecord (3.0.6) lib/active_record/connection_adapters/abstract/connection_pool.rb:354:in `call'
actionpack (3.0.6) lib/action_dispatch/middleware/callbacks.rb:46:in `block in call'
activesupport (3.0.6) lib/active_support/callbacks.rb:416:in `_run_call_callbacks'
actionpack (3.0.6) lib/action_dispatch/middleware/callbacks.rb:44:in `call'
rack (1.2.2) lib/rack/sendfile.rb:107:in `call'
actionpack (3.0.6) lib/action_dispatch/middleware/remote_ip.rb:48:in `call'
actionpack (3.0.6) lib/action_dispatch/middleware/show_exceptions.rb:47:in `call'
railties (3.0.6) lib/rails/rack/logger.rb:13:in `call'
rack (1.2.2) lib/rack/runtime.rb:17:in `call'
activesupport (3.0.6) lib/active_support/cache/strategy/local_cache.rb:72:in `call'
rack (1.2.2) lib/rack/lock.rb:11:in `block in call'
<internal:prelude>:10:in `synchronize'
rack (1.2.2) lib/rack/lock.rb:11:in `call'
actionpack (3.0.6) lib/action_dispatch/middleware/static.rb:30:in `call'
railties (3.0.6) lib/rails/application.rb:168:in `call'
railties (3.0.6) lib/rails/application.rb:77:in `method_missing'
railties (3.0.6) lib/rails/rack/log_tailer.rb:14:in `call'
rack (1.2.2) lib/rack/content_length.rb:13:in `call'
rack (1.2.2) lib/rack/handler/webrick.rb:52:in `service'
c:/Ruby192/lib/ruby/1.9.1/webrick/httpserver.rb:111:in `service'
c:/Ruby192/lib/ruby/1.9.1/webrick/httpserver.rb:70:in `run'
c:/Ruby192/lib/ruby/1.9.1/webrick/server.rb:183:in `block in start_thread'

是否可以使用form_for-tag编辑类属性？

解决方法

jdc回答了这个问题,但未显示您请求的实际实现.正如jdc所说,你需要包含一些ActiveModel模块,这将为你的ruby类提供你需要的功能.

看起来你需要ActiveModel :: Naming和ActiveModel :: AttributeMethods.

class Entry
  extend ActiveModel::Naming
  include ActiveModel::AttributeMethods
end

第一行将为您提供model_name,第二行允许您的模型与表单助手一起使用.您还可以使用其他行：查看在jdc的答案或Rails API中链接的博客.

更多链接详细信息：

http://www.rubyinside.com/rails-3-0s-activemodel-how-to-give-ruby-classes-some-activerecord-magic-2937.html

http://railscasts.com/episodes/219-active-model

（编辑：李大同）

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