我多年来一直试图解决这个问题，但无法弄明白。
我有一个这样的表格（取出很多其他领域）
<% form_for @machine_enquiry, machine_enquiry_path(@machine_enquiry) do|me_form| %>
<% me_form.fields_for :messages_attributes do |f| %>
<%= f.text_field :title -%>
<% end %>
<%= me_form.submit 'Send message' %>
<% end %>
像
这样的更新操作@machine_enquiry = MachineEnquiry.find(params[:id])
@machine_enquiry.update_attributes(params[:machine_enquiry]
还有一个machine_enquiry类：
class MachineEnquiry < ActiveRecord::Base
has_many :messages, :as => :messagable, :dependent => :destroy
accepts_nested_attributes_for :messages
end
我收到的错误是这样的：
NoMethodError in Machine enquiriesController#update
undefined method `stringify_keys' for "2":String
RAILS_ROOT: C:/INSTAN~2/rails_apps/Macrotec28th
Application Trace | Framework Trace | Full Trace
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/nested_attributes.rb:294:in `assign_nested_attributes_for_collection_association'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/nested_attributes.rb:293:in `each'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/nested_attributes.rb:293:in `assign_nested_attributes_for_collection_association'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/nested_attributes.rb:215:in `messages_attributes='
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/base.rb:2745:in `send'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/base.rb:2745:in `attributes='
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/base.rb:2741:in `each'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/base.rb:2741:in `attributes='
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/base.rb:2627:in `update_attributes'
C:/INSTAN~2/rails_apps/Macrotec28th/app/controllers/machine_enquiries_controller.rb:74:in `update'
C:/INSTAN~2/rails_apps/Macrotec28th/app/controllers/machine_enquiries_controller.rb:72:in `update'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/nested_attributes.rb:294:in `assign_nested_attributes_for_collection_association'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/nested_attributes.rb:293:in `each'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/nested_attributes.rb:293:in `assign_nested_attributes_for_collection_association'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/nested_attributes.rb:215:in `messages_attributes='
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/base.rb:2745:in `send'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/base.rb:2745:in `attributes='
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/base.rb:2741:in `each'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/base.rb:2741:in `attributes='
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/base.rb:2627:in `update_attributes'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/mime_responds.rb:106:in `call'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/mime_responds.rb:106:in `respond_to'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/base.rb:1322:in `send'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/base.rb:1322:in `perform_action_without_filters'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/filters.rb:617:in `call_filters'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/filters.rb:610:in `perform_action_without_benchmark'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.2/lib/active_support/core_ext/benchmark.rb:17:in `ms'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.2/lib/active_support/core_ext/benchmark.rb:10:in `realtime'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.2/lib/active_support/core_ext/benchmark.rb:17:in `ms'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/rescue.rb:160:in `perform_action_without_flash'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/flash.rb:141:in `perform_action'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/base.rb:523:in `send'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/base.rb:523:in `process_without_filters'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/filters.rb:606:in `process'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/base.rb:391:in `process'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/base.rb:386:in `call'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/routing/route_set.rb:433:in `call'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/dispatcher.rb:88:in `dispatch'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/dispatcher.rb:111:in `_call'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/dispatcher.rb:82:in `initialize'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/query_cache.rb:29:in `call'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/query_cache.rb:29:in `call'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/query_cache.rb:34:in `cache'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/query_cache.rb:9:in `cache'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/query_cache.rb:28:in `call'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:361:in `call'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/vendor/rack-1.0/rack/head.rb:9:in `call'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/vendor/rack-1.0/rack/methodoverride.rb:24:in `call'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/params_parser.rb:15:in `call'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/rewindable_input.rb:25:in `call'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/session/cookie_store.rb:93:in `call'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/reloader.rb:9:in `call'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/failsafe.rb:11:in `call'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/vendor/rack-1.0/rack/lock.rb:11:in `call'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/vendor/rack-1.0/rack/lock.rb:11:in `synchronize'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/vendor/rack-1.0/rack/lock.rb:11:in `call'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/dispatcher.rb:106:in `call'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/cgi_process.rb:44:in `dispatch_cgi'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/dispatcher.rb:102:in `dispatch_cgi'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/dispatcher.rb:28:in `dispatch'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel/rails.rb:76:in `process'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel/rails.rb:74:in `synchronize'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel/rails.rb:74:in `process'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel.rb:159:in `process_client'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel.rb:158:in `each'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel.rb:158:in `process_client'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel.rb:285:in `run'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel.rb:285:in `initialize'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel.rb:285:in `new'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel.rb:285:in `run'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel.rb:268:in `initialize'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel.rb:268:in `new'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel.rb:268:in `run'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel/configurator.rb:282:in `run'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel/configurator.rb:281:in `each'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel/configurator.rb:281:in `run'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/bin/mongrel_rails:128:in `run'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel/command.rb:212:in `run'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/bin/mongrel_rails:281
C:/INSTAN~2/ruby/bin/mongrel_rails:19:in `load'
C:/INSTAN~2/ruby/bin/mongrel_rails:19
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/nested_attributes.rb:294:in `assign_nested_attributes_for_collection_association'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/nested_attributes.rb:293:in `each'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/nested_attributes.rb:293:in `assign_nested_attributes_for_collection_association'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/nested_attributes.rb:215:in `messages_attributes='
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/base.rb:2745:in `send'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/base.rb:2745:in `attributes='
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/base.rb:2741:in `each'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/base.rb:2741:in `attributes='
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/base.rb:2627:in `update_attributes'
C:/INSTAN~2/rails_apps/Macrotec28th/app/controllers/machine_enquiries_controller.rb:74:in `update'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/mime_responds.rb:106:in `call'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/mime_responds.rb:106:in `respond_to'
C:/INSTAN~2/rails_apps/Macrotec28th/app/controllers/machine_enquiries_controller.rb:72:in `update'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/base.rb:1322:in `send'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/base.rb:1322:in `perform_action_without_filters'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/filters.rb:617:in `call_filters'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/filters.rb:610:in `perform_action_without_benchmark'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.2/lib/active_support/core_ext/benchmark.rb:17:in `ms'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.2/lib/active_support/core_ext/benchmark.rb:10:in `realtime'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.2/lib/active_support/core_ext/benchmark.rb:17:in `ms'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/benchmarking.rb:68:in `perform_action_without_rescue'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/rescue.rb:160:in `perform_action_without_flash'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/flash.rb:141:in `perform_action'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/base.rb:523:in `send'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/base.rb:523:in `process_without_filters'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/filters.rb:606:in `process'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/base.rb:391:in `process'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/base.rb:386:in `call'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/routing/route_set.rb:433:in `call'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/dispatcher.rb:88:in `dispatch'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/dispatcher.rb:111:in `_call'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/dispatcher.rb:82:in `initialize'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/query_cache.rb:29:in `call'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/query_cache.rb:29:in `call'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/query_cache.rb:34:in `cache'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/query_cache.rb:9:in `cache'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/query_cache.rb:28:in `call'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:361:in `call'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/vendor/rack-1.0/rack/head.rb:9:in `call'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/vendor/rack-1.0/rack/methodoverride.rb:24:in `call'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/params_parser.rb:15:in `call'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/rewindable_input.rb:25:in `call'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/session/cookie_store.rb:93:in `call'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/reloader.rb:9:in `call'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/failsafe.rb:11:in `call'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/vendor/rack-1.0/rack/lock.rb:11:in `call'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/vendor/rack-1.0/rack/lock.rb:11:in `synchronize'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/vendor/rack-1.0/rack/lock.rb:11:in `call'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/dispatcher.rb:106:in `call'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/cgi_process.rb:44:in `dispatch_cgi'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/dispatcher.rb:102:in `dispatch_cgi'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.2/lib/action_controller/dispatcher.rb:28:in `dispatch'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel/rails.rb:76:in `process'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel/rails.rb:74:in `synchronize'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel/rails.rb:74:in `process'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel.rb:159:in `process_client'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel.rb:158:in `each'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel.rb:158:in `process_client'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel.rb:285:in `run'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel.rb:285:in `initialize'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel.rb:285:in `new'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel.rb:285:in `run'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel.rb:268:in `initialize'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel.rb:268:in `new'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel.rb:268:in `run'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel/configurator.rb:282:in `run'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel/configurator.rb:281:in `each'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel/configurator.rb:281:in `run'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/bin/mongrel_rails:128:in `run'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/lib/mongrel/command.rb:212:in `run'
C:/INSTAN~2/ruby/lib/ruby/gems/1.8/gems/mongrel-1.1.2-x86-mswin32/bin/mongrel_rails:281
C:/INSTAN~2/ruby/bin/mongrel_rails:19:in `load'
C:/INSTAN~2/ruby/bin/mongrel_rails:19
Request
Parameters:
{"commit"=>"Send message",
"_method"=>"put",
"machine_enquiry"=>{"messages_attributes"=>{"message"=>"2",
"title"=>"1",
"message_type_id"=>"1",
"contact_detail_ids"=>["1",
"11"]}},
"id"=>"2",
"datetime"=>""}
为什么我收到此错误？任何人都可以帮忙吗？
答案 0 :(得分：2)
看一下跟踪中的参数，我认为表格在某些方面可能不正确，但如果没有更多的信息，很难说。你现在从表格中获得的参数是（为了易读性而重新格式化）：
{ "commit" => "Send message",
"_method" => "put",
"machine_enquiry" => {
"messages_attributes" => {
"message" => "2",
"title" => "1",
"message_type_id" => "1",
"contact_detail_ids" => [ "1", "11" ]
}
},
"id" => "2",
"datetime" => ""
}
但他们应该看起来像：
{ "commit" => "Send message",
"_method" => "put",
"machine_enquiry" => {
"messages_attributes" => {
0 => {
"message" => "2", # this may still be wrong
"title" => "1",
"message_type_id" => "1",
"contact_detail_ids" => [ "1", "11" ]
}
}
},
"id" => "2",
"datetime" => ""
}
请注意，直接位于messages_attributes内的哈希现在更深层次了。表单的嵌套属性部分应包含一个哈希，其中包含正在创建或编辑的每条消息的唯一键。错误的来源是表单格式解析器将message，title，message_id和contact_detail_ids视为四个单独消息的唯一键，但关联的值这些关键并不像预期的那样是哈希。
我在调整后的例子中发出了一条评论，我有点不确定。如果没有完整地看到表单或Message类，很难知道这是否是消息的属性，或者它应该是消息ID。顺便说一句，只有在您编辑现有消息时才应包含消息ID。
有exhaustive explanation of the Rails forms micro-format可用。搜索has_many以查找相关部分。
这种格式错误的params哈希的来源几乎肯定是你的form_for。如果您包含整个表单，则可能有人可以帮助您诊断表单创建错误的原因。
<强>更新
在查看完整表格后，问题就出在这一行：
<% me_form.fields_for :messages_attributes do |f| %>
应该是：
<% me_form.fields_for :messages do |f| %>
fields_for帮助程序需要关联名称才能正常运行。我在查看表单时看到的另一个问题是，您用于联系人的单选按钮需要将name更改为machine_enquiry[messages_attributes][0][contact_detail_ids][]之类的内容。您可能需要找到一种方法来使用表单助手生成这些单选按钮，以便他们可以获得正确的消息ID。