Nomethod错误不正确需要解决答案

【问题标题】：Nomethod Error not correct need solutionNomethod错误不正确需要解决
【发布时间】：2014-09-26 19:14:05
【问题描述】：

我已对此进行了编辑，因为我之前得到的答案不是修复...我有一个县列表，其中包含位置列表。我希望能够显示一个县列表，单击该列表可以显示另一个页面，其中包含其中的位置列表。我无法理解为什么以下设置不起作用 - 我已经对这封信进行了最初建议的更正，并得到了与发布的完全相同的错误。有人可以准确地解决需要编码的内容来解决这个问题吗 - 非常感谢任何帮助...我已经设置了我的 Active Record

class County < ActiveRecord::Base
    has_many :locations
end



class Location < ActiveRecord::Base
        belongs_to :county
   end

控制器如下：

class LocationsController < ApplicationController
   def index
      @locations = Location.scoped
      @locations = @locations.where(county_id: params[:county_id]) if params[:county_id].present?
   end

   def show
      @location = Location.find(params[:id])

   end 
end

class CountiesController < ApplicationController
   def index
      @counties = County.all
   end

   def show
      @county = County.find(params[:id])

   end 
end

位置索引视图

<h1> Locations: index</h1>

<ul>
  <% @locations.each do |location| %>
     <li><%= link_to location.name, location %></li>
     <% end %>
</ul>

县索引视图

<p>List of all the locations in <%= @county %></p>

<ul>
  <%= @counties.each do |county| %>
      <li><%= link_to "locations in #{county.id}", locations_path(location_id: location.id) %></li>
       <% end %>
</ul>

我的路线是：

resources :counties
resources :locations

尝试查看县的错误如下：

NameError in Counties#index
Showing /home/ubuntu/workspace/static_site/app/views/counties/index.html.erb where line #7 raised:

undefined local variable or method `location' for #<#<Class:0x00000005a7e108>:0x00000005a7d500>

app/views/counties/index.html.erb:7:in `block in _app_views_counties_index_html_erb__3017893529265312437_33668340'

完整的跟踪：

activerecord (4.1.5) lib/active_record/relation/delegation.rb:46:in `each'
activerecord (4.1.5) lib/active_record/relation/delegation.rb:46:in `each'
app/views/counties/index.html.erb:6:in `_app_views_counties_index_html_erb__3017893529265312437_33668340'
actionview (4.1.5) lib/action_view/template.rb:145:in `block in render'
activesupport (4.1.5) lib/active_support/notifications.rb:161:in `instrument'
actionview (4.1.5) lib/action_view/template.rb:339:in `instrument'
actionview (4.1.5) lib/action_view/template.rb:143:in `render'
actionview (4.1.5) lib/action_view/renderer/template_renderer.rb:55:in `block (2 levels) in render_template'
actionview (4.1.5) lib/action_view/renderer/abstract_renderer.rb:38:in `block in instrument'
activesupport (4.1.5) lib/active_support/notifications.rb:159:in `block in instrument'
activesupport (4.1.5) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (4.1.5) lib/active_support/notifications.rb:159:in `instrument'
actionview (4.1.5) lib/action_view/renderer/abstract_renderer.rb:38:in `instrument'
actionview (4.1.5) lib/action_view/renderer/template_renderer.rb:54:in `block in render_template'
actionview (4.1.5) lib/action_view/renderer/template_renderer.rb:62:in `render_with_layout'
actionview (4.1.5) lib/action_view/renderer/template_renderer.rb:53:in `render_template'
actionview (4.1.5) lib/action_view/renderer/template_renderer.rb:17:in `render'
actionview (4.1.5) lib/action_view/renderer/renderer.rb:42:in `render_template'
actionview (4.1.5) lib/action_view/renderer/renderer.rb:23:in `render'
actionview (4.1.5) lib/action_view/rendering.rb:99:in `_render_template'
actionpack (4.1.5) lib/action_controller/metal/streaming.rb:217:in `_render_template'
actionview (4.1.5) lib/action_view/rendering.rb:82:in `render_to_body'
actionpack (4.1.5) lib/action_controller/metal/rendering.rb:32:in `render_to_body'
actionpack (4.1.5) lib/action_controller/metal/renderers.rb:32:in `render_to_body'
actionpack (4.1.5) lib/abstract_controller/rendering.rb:25:in `render'
actionpack (4.1.5) lib/action_controller/metal/rendering.rb:16:in `render'
actionpack (4.1.5) lib/action_controller/metal/instrumentation.rb:41:in `block (2 levels) in render'
activesupport (4.1.5) lib/active_support/core_ext/benchmark.rb:12:in `block in ms'
/usr/local/rvm/rubies/ruby-2.1.1/lib/ruby/2.1.0/benchmark.rb:294:in `realtime'
activesupport (4.1.5) lib/active_support/core_ext/benchmark.rb:12:in `ms'
actionpack (4.1.5) lib/action_controller/metal/instrumentation.rb:41:in `block in render'
actionpack (4.1.5) lib/action_controller/metal/instrumentation.rb:84:in `cleanup_view_runtime'
activerecord (4.1.5) lib/active_record/railties/controller_runtime.rb:25:in `cleanup_view_runtime'
actionpack (4.1.5) lib/action_controller/metal/instrumentation.rb:40:in `render'
actionpack (4.1.5) lib/action_controller/metal/implicit_render.rb:10:in `default_render'
actionpack (4.1.5) lib/action_controller/metal/implicit_render.rb:5:in `send_action'
actionpack (4.1.5) lib/abstract_controller/base.rb:189:in `process_action'
actionpack (4.1.5) lib/action_controller/metal/rendering.rb:10:in `process_action'
actionpack (4.1.5) lib/abstract_controller/callbacks.rb:20:in `block in process_action'
activesupport (4.1.5) lib/active_support/callbacks.rb:113:in `call'
activesupport (4.1.5) lib/active_support/callbacks.rb:113:in `call'
activesupport (4.1.5) lib/active_support/callbacks.rb:229:in `block in halting'
activesupport (4.1.5) lib/active_support/callbacks.rb:229:in `call'
activesupport (4.1.5) lib/active_support/callbacks.rb:229:in `block in halting'
activesupport (4.1.5) lib/active_support/callbacks.rb:166:in `call'
activesupport (4.1.5) lib/active_support/callbacks.rb:166:in `block in halting'
activesupport (4.1.5) lib/active_support/callbacks.rb:166:in `call'
activesupport (4.1.5) lib/active_support/callbacks.rb:166:in `block in halting'
activesupport (4.1.5) lib/active_support/callbacks.rb:166:in `call'
activesupport (4.1.5) lib/active_support/callbacks.rb:166:in `block in halting'
activesupport (4.1.5) lib/active_support/callbacks.rb:86:in `call'
activesupport (4.1.5) lib/active_support/callbacks.rb:86:in `run_callbacks'
actionpack (4.1.5) lib/abstract_controller/callbacks.rb:19:in `process_action'
actionpack (4.1.5) lib/action_controller/metal/rescue.rb:29:in `process_action'
actionpack (4.1.5) lib/action_controller/metal/instrumentation.rb:31:in `block in process_action'
activesupport (4.1.5) lib/active_support/notifications.rb:159:in `block in instrument'
activesupport (4.1.5) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (4.1.5) lib/active_support/notifications.rb:159:in `instrument'
actionpack (4.1.5) lib/action_controller/metal/instrumentation.rb:30:in `process_action'
actionpack (4.1.5) lib/action_controller/metal/params_wrapper.rb:250:in `process_action'
activerecord (4.1.5) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
actionpack (4.1.5) lib/abstract_controller/base.rb:136:in `process'
actionview (4.1.5) lib/action_view/rendering.rb:30:in `process'
actionpack (4.1.5) lib/action_controller/metal.rb:196:in `dispatch'
actionpack (4.1.5) lib/action_controller/metal/rack_delegation.rb:13:in `dispatch'
actionpack (4.1.5) lib/action_controller/metal.rb:232:in `block in action'
actionpack (4.1.5) lib/action_dispatch/routing/route_set.rb:82:in `call'
actionpack (4.1.5) lib/action_dispatch/routing/route_set.rb:82:in `dispatch'
actionpack (4.1.5) lib/action_dispatch/routing/route_set.rb:50:in `call'
actionpack (4.1.5) lib/action_dispatch/journey/router.rb:71:in `block in call'
actionpack (4.1.5) lib/action_dispatch/journey/router.rb:59:in `each'
actionpack (4.1.5) lib/action_dispatch/journey/router.rb:59:in `call'
actionpack (4.1.5) lib/action_dispatch/routing/route_set.rb:678:in `call'
rack (1.5.2) lib/rack/etag.rb:23:in `call'
rack (1.5.2) lib/rack/conditionalget.rb:25:in `call'
rack (1.5.2) lib/rack/head.rb:11:in `call'
actionpack (4.1.5) lib/action_dispatch/middleware/params_parser.rb:27:in `call'
actionpack (4.1.5) lib/action_dispatch/middleware/flash.rb:254:in `call'
rack (1.5.2) lib/rack/session/abstract/id.rb:225:in `context'
rack (1.5.2) lib/rack/session/abstract/id.rb:220:in `call'
actionpack (4.1.5) lib/action_dispatch/middleware/cookies.rb:560:in `call'
activerecord (4.1.5) lib/active_record/query_cache.rb:36:in `call'
activerecord (4.1.5) lib/active_record/connection_adapters/abstract/connection_pool.rb:621:in `call'
activerecord (4.1.5) lib/active_record/migration.rb:380:in `call'
actionpack (4.1.5) lib/action_dispatch/middleware/callbacks.rb:29:in `block in call'
activesupport (4.1.5) lib/active_support/callbacks.rb:82:in `run_callbacks'
actionpack (4.1.5) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
actionpack (4.1.5) lib/action_dispatch/middleware/reloader.rb:73:in `call'
actionpack (4.1.5) lib/action_dispatch/middleware/remote_ip.rb:76:in `call'
actionpack (4.1.5) lib/action_dispatch/middleware/debug_exceptions.rb:17:in `call'
actionpack (4.1.5) lib/action_dispatch/middleware/show_exceptions.rb:30:in `call'
railties (4.1.5) lib/rails/rack/logger.rb:38:in `call_app'
railties (4.1.5) lib/rails/rack/logger.rb:20:in `block in call'
activesupport (4.1.5) lib/active_support/tagged_logging.rb:68:in `block in tagged'
activesupport (4.1.5) lib/active_support/tagged_logging.rb:26:in `tagged'
activesupport (4.1.5) lib/active_support/tagged_logging.rb:68:in `tagged'
railties (4.1.5) lib/rails/rack/logger.rb:20:in `call'
actionpack (4.1.5) lib/action_dispatch/middleware/request_id.rb:21:in `call'
rack (1.5.2) lib/rack/methodoverride.rb:21:in `call'
rack (1.5.2) lib/rack/runtime.rb:17:in `call'
activesupport (4.1.5) lib/active_support/cache/strategy/local_cache_middleware.rb:26:in `call'
rack (1.5.2) lib/rack/lock.rb:17:in `call'
actionpack (4.1.5) lib/action_dispatch/middleware/static.rb:64:in `call'
rack (1.5.2) lib/rack/sendfile.rb:112:in `call'
railties (4.1.5) lib/rails/engine.rb:514:in `call'
railties (4.1.5) lib/rails/application.rb:144:in `call'
rack (1.5.2) lib/rack/lock.rb:17:in `call'
rack (1.5.2) lib/rack/content_length.rb:14:in `call'
rack (1.5.2) lib/rack/handler/webrick.rb:60:in `service'
/usr/local/rvm/rubies/ruby-2.1.1/lib/ruby/2.1.0/webrick/httpserver.rb:138:in `service'
/usr/local/rvm/rubies/ruby-2.1.1/lib/ruby/2.1.0/webrick/httpserver.rb:94:in `run'
/usr/local/rvm/rubies/ruby-2.1.1/lib/ruby/2.1.0/webrick/server.rb:295:in `block in start_thread'

我已经为此工作了好几天，因此非常感谢在制定解决方案方面的任何帮助。

【问题讨论】：

标签： ruby-on-rails activerecord model-view-controller routes

【解决方案1】：

您的县索引视图没有尝试定义location 变量，但您尝试引用location.id。当然，这失败了。你想要location 是什么？

如果意图链接到位置的索引视图，范围为给定的县，您需要修复您的路线，以便嵌套 location...

resources :counties do
 resources :locations
end

然后修正你对locations_path的使用：

link_to "locations in #{county.id}", locations_path(county)

【讨论】：

我只是为了发布相同的答案:)
我做了这两项更改，但没有任何区别？
当我按照建议更改路线时出现同样的错误，加上 link_to “#{county.id} 中的位置”，locations_path(county)
大家好，还有其他建议，这仍然不是解决方案吗？

【解决方案2】：

坦率地说，对于刚开始使用 RoR 的人来说，这个地方毫无用处 - 我提出了一个显然很容易解决的问题。如果只有你和一台笔记本电脑，这些东西并不容易学习。无论如何，我的问题的答案如下：

<p>List of all counties</p>

<ul>
  <% @counties.each do |county| %>
      <li><%= link_to "Locations in #{county.name}", county_locations_path(county) %></li>
  <% end %>
</ul>

class CountiesController < ApplicationController
   def index
      @counties = County.all
   end

   def show
      @county = County.find(params[:id])

   end 
end

 resources :counties do
   resources :locations
 end

class LocationsController < ApplicationController
   def index
      if params[:county_id]
         @county=County.find(params[:county_id])
         @locations = @county.locations
      else
         redirect_to counties_path
      end
   end

   def show
      @location = Location.find(params[:id])

   end 
end

【讨论】：

【解决方案3】：

<h1> Locations for </h1>  

    <%=@county.name%>

        <ul>
          <% @locations.each do |location| %>
             <li><%= link_to location.name, [@county,location] %></li>
          <% end %>
        </ul>

【讨论】：