错误：未定义的方法`MODEL_NAME“的NilClass：类

Question

我与我的edit.html.erb，如果我想在我的红宝石应用程序做一些修改，然后这个错误哈瓦一个问题出现：

未定义的方法`MODEL_NAME”对于NilClass：类

<%- model_class = @mytime.class -%> 
<h1><%=t '.title', :default => t('helpers.titles.edit', :model =>model_class.model_name.human, 
:default => "Edit #{model_class.model_name.human}") %></h1> 
<%= render :partial => 'form' %> 

我Fulltrace：

app/views/mytimes/edit.html.erb:3:in `_app_views_mytimes_edit_html_erb___308492073099851536_70125215393580' 
actionpack (3.2.3) lib/action_view/template.rb:143:in `block in render' 
activesupport (3.2.3) lib/active_support/notifications.rb:125:in `instrument' 
actionpack (3.2.3) lib/action_view/template.rb:141:in `render' 
actionpack (3.2.3) lib/action_view/renderer/template_renderer.rb:47:in `block (2 levels) in render_template' 
actionpack (3.2.3) lib/action_view/renderer/abstract_renderer.rb:38:in `block in instrument' 
activesupport (3.2.3) lib/active_support/notifications.rb:123:in `block in instrument' 
activesupport (3.2.3) lib/active_support/notifications/instrumenter.rb:20:in `instrument' 
activesupport (3.2.3) lib/active_support/notifications.rb:123:in `instrument' 
actionpack (3.2.3) lib/action_view/renderer/abstract_renderer.rb:38:in `instrument' 
actionpack (3.2.3) lib/action_view/renderer/template_renderer.rb:46:in `block in render_template' 
actionpack (3.2.3) lib/action_view/renderer/template_renderer.rb:54:in `render_with_layout' 
actionpack (3.2.3) lib/action_view/renderer/template_renderer.rb:45:in `render_template' 
actionpack (3.2.3) lib/action_view/renderer/template_renderer.rb:18:in `render' 
actionpack (3.2.3) lib/action_view/renderer/renderer.rb:36:in `render_template' 
actionpack (3.2.3) lib/action_view/renderer/renderer.rb:17:in `render' 
actionpack (3.2.3) lib/abstract_controller/rendering.rb:110:in `_render_template' 
actionpack (3.2.3) lib/action_controller/metal/streaming.rb:225:in `_render_template' 
actionpack (3.2.3) lib/abstract_controller/rendering.rb:103:in `render_to_body' 
actionpack (3.2.3) lib/action_controller/metal/renderers.rb:28:in `render_to_body' 
actionpack (3.2.3) lib/action_controller/metal/compatibility.rb:50:in `render_to_body' 
actionpack (3.2.3) lib/abstract_controller/rendering.rb:88:in `render' 
actionpack (3.2.3) lib/action_controller/metal/rendering.rb:16:in `render' 
actionpack (3.2.3) lib/action_controller/metal/instrumentation.rb:40:in `block (2 levels) in render' 
activesupport (3.2.3) lib/active_support/core_ext/benchmark.rb:5:in `block in ms' 
/Users/sinaoberle/.rbenv/versions/1.9.3-p0/lib/ruby/1.9.1/benchmark.rb:295:in `realtime' 
activesupport (3.2.3) lib/active_support/core_ext/benchmark.rb:5:in `ms' 
actionpack (3.2.3) lib/action_controller/metal/instrumentation.rb:40:in `block in render' 
actionpack (3.2.3) lib/action_controller/metal/instrumentation.rb:83:in `cleanup_view_runtime' 
activerecord (3.2.3) lib/active_record/railties/controller_runtime.rb:24:in `cleanup_view_runtime' 
actionpack (3.2.3) lib/action_controller/metal/instrumentation.rb:39:in `render' 
actionpack (3.2.3) lib/action_controller/metal/implicit_render.rb:10:in `default_render' 
actionpack (3.2.3) lib/action_controller/metal/implicit_render.rb:4:in `send_action' 
actionpack (3.2.3) lib/abstract_controller/base.rb:167:in `process_action' 
actionpack (3.2.3) lib/action_controller/metal/rendering.rb:10:in `process_action' 
actionpack (3.2.3) lib/abstract_controller/callbacks.rb:18:in `block in process_action' 
activesupport (3.2.3) lib/active_support/callbacks.rb:425:in `_run__1584935368947607784__process_action__332388991620009023__callbacks' 
activesupport (3.2.3) lib/active_support/callbacks.rb:405:in `__run_callback' 
activesupport (3.2.3) lib/active_support/callbacks.rb:385:in `_run_process_action_callbacks' 
activesupport (3.2.3) lib/active_support/callbacks.rb:81:in `run_callbacks' 
actionpack (3.2.3) lib/abstract_controller/callbacks.rb:17:in `process_action' 
actionpack (3.2.3) lib/action_controller/metal/rescue.rb:29:in `process_action' 
actionpack (3.2.3) lib/action_controller/metal/instrumentation.rb:30:in `block in process_action' 
activesupport (3.2.3) lib/active_support/notifications.rb:123:in `block in instrument' 
activesupport (3.2.3) lib/active_support/notifications/instrumenter.rb:20:in `instrument' 
activesupport (3.2.3) lib/active_support/notifications.rb:123:in `instrument' 
actionpack (3.2.3) lib/action_controller/metal/instrumentation.rb:29:in `process_action' 
actionpack (3.2.3) lib/action_controller/metal/params_wrapper.rb:205:in `process_action' 
activerecord (3.2.3) lib/active_record/railties/controller_runtime.rb:18:in `process_action' 
actionpack (3.2.3) lib/abstract_controller/base.rb:121:in `process' 
actionpack (3.2.3) lib/abstract_controller/rendering.rb:45:in `process' 
actionpack (3.2.3) lib/action_controller/metal.rb:203:in `dispatch' 
actionpack (3.2.3) lib/action_controller/metal/rack_delegation.rb:14:in `dispatch' 
actionpack (3.2.3) lib/action_controller/metal.rb:246:in `block in action' 
actionpack (3.2.3) lib/action_dispatch/routing/route_set.rb:73:in `call' 
actionpack (3.2.3) lib/action_dispatch/routing/route_set.rb:73:in `dispatch' 
actionpack (3.2.3) lib/action_dispatch/routing/route_set.rb:36:in `call' 
journey (1.0.3) lib/journey/router.rb:68:in `block in call' 
journey (1.0.3) lib/journey/router.rb:56:in `each' 
journey (1.0.3) lib/journey/router.rb:56:in `call' 
actionpack (3.2.3) lib/action_dispatch/routing/route_set.rb:600:in `call' 
actionpack (3.2.3) lib/action_dispatch/middleware/best_standards_support.rb:17:in `call' 
rack (1.4.1) lib/rack/etag.rb:23:in `call' 
rack (1.4.1) lib/rack/conditionalget.rb:25:in `call' 
actionpack (3.2.3) lib/action_dispatch/middleware/head.rb:14:in `call' 
actionpack (3.2.3) lib/action_dispatch/middleware/params_parser.rb:21:in `call' 
actionpack (3.2.3) lib/action_dispatch/middleware/flash.rb:242:in `call' 
rack (1.4.1) lib/rack/session/abstract/id.rb:205:in `context' 
rack (1.4.1) lib/rack/session/abstract/id.rb:200:in `call' 
actionpack (3.2.3) lib/action_dispatch/middleware/cookies.rb:338:in `call' 
activerecord (3.2.3) lib/active_record/query_cache.rb:64:in `call' 
activerecord (3.2.3) lib/active_record/connection_adapters/abstract/connection_pool.rb:467:in `call' 
actionpack (3.2.3) lib/action_dispatch/middleware/callbacks.rb:28:in `block in call' 
activesupport (3.2.3) lib/active_support/callbacks.rb:405:in `_run__344157926311310900__call__3627087792160188865__callbacks' 
activesupport (3.2.3) lib/active_support/callbacks.rb:405:in `__run_callback' 
activesupport (3.2.3) lib/active_support/callbacks.rb:385:in `_run_call_callbacks' 
activesupport (3.2.3) lib/active_support/callbacks.rb:81:in `run_callbacks' 
actionpack (3.2.3) lib/action_dispatch/middleware/callbacks.rb:27:in `call' 
actionpack (3.2.3) lib/action_dispatch/middleware/reloader.rb:65:in `call' 
actionpack (3.2.3) lib/action_dispatch/middleware/remote_ip.rb:31:in `call' 
actionpack (3.2.3) lib/action_dispatch/middleware/debug_exceptions.rb:16:in `call' 
actionpack (3.2.3) lib/action_dispatch/middleware/show_exceptions.rb:56:in `call' 
railties (3.2.3) lib/rails/rack/logger.rb:26:in `call_app' 
railties (3.2.3) lib/rails/rack/logger.rb:16:in `call' 
actionpack (3.2.3) lib/action_dispatch/middleware/request_id.rb:22:in `call' 
rack (1.4.1) lib/rack/methodoverride.rb:21:in `call' 
rack (1.4.1) lib/rack/runtime.rb:17:in `call' 
activesupport (3.2.3) lib/active_support/cache/strategy/local_cache.rb:72:in `call' 
rack (1.4.1) lib/rack/lock.rb:15:in `call' 
actionpack (3.2.3) lib/action_dispatch/middleware/static.rb:62:in `call' 
railties (3.2.3) lib/rails/engine.rb:479:in `call' 
railties (3.2.3) lib/rails/application.rb:220:in `call' 
rack (1.4.1) lib/rack/content_length.rb:14:in `call' 
railties (3.2.3) lib/rails/rack/log_tailer.rb:14:in `call' 
rack (1.4.1) lib/rack/handler/webrick.rb:59:in `service' 
/Users/sinaoberle/.rbenv/versions/1.9.3-p0/lib/ruby/1.9.1/webrick/httpserver.rb:138:in `service' 
/Users/sinaoberle/.rbenv/versions/1.9.3-p0/lib/ruby/1.9.1/webrick/httpserver.rb:94:in `run' 
/Users/sinaoberle/.rbenv/versions/1.9.3-p0/lib/ruby/1.9.1/webrick/server.rb:191:in `block in start_thread' 

edit.html.erb

<%- model_class = @mytime.class -%> 
<h1><%=t '.title', :default => t('helpers.titles.edit', :model => model_class.model_name.human, 
           :default => "Edit #{model_class.model_name.human}") %></h1> 
<%= render :partial => 'form' %> 

荫感谢您的帮助！

Answer 1

如Highcode在评论上面说的 - 好像@mytime没有设置，当你得到它的类它给你NilClass。当然，它根本没有model_name方法。