我有一个棘手的场景我需要实现，无法弄清楚如何做到这一点。我正在尝试创建一个表单，将其数据以标记为“message”的哈希值传递给控制器，然后控制器将创建一个消息对象，但我不能使用form_for，因为我需要使用hidden_field标记而不是hidden_field。
以下是我目前的表格：
=form_tag(:action => 'create', :controller => 'messages', :method => :get) do
=text_area :message, :message, :size => '40x5'
=hidden_field_tag(:message, :subject => "RE:#{@message.subject}")
=hidden_field_tag(:message, :parent => @message.id)
=hidden_field_tag(:message, :receiver => @message.sender)
=submit_tag 'Reply'
我希望控制器接收：
{"message"=>"{:message=>"How are you?", :subject=>"Hi", :parent=>nil, :receiver=>2}", "commit"=>"Reply", "method"=>"get", "action"=>"create", "controller"=>"messages"}
但是，我收到了：
{"message"=>"{:receiver=>2}", "commit"=>"Reply", "method"=>"get", "action"=>"create", "controller"=>"messages"}
并且文本区域的值被赋予我正在回复的消息的值。 任何人都可以帮助我吗？
编辑：在实施罗素答案后，我现在收到：
Message(#39922460) expected, got String(#15633780)
以下是完整的跟踪：
activerecord (3.2.13) lib/active_record/associations/association.rb:204:in `raise_on_type_mismatch'
activerecord (3.2.13) lib/active_record/associations/belongs_to_association.rb:6:in `replace'
activerecord (3.2.13) lib/active_record/associations/singular_association.rb:17:in `writer'
activerecord (3.2.13) lib/active_record/associations/builder/association.rb:51:in `block in define_writers'
activerecord (3.2.13) lib/active_record/attribute_assignment.rb:85:in `block in assign_attributes'
activerecord (3.2.13) lib/active_record/attribute_assignment.rb:78:in `each'
activerecord (3.2.13) lib/active_record/attribute_assignment.rb:78:in `assign_attributes'
activerecord (3.2.13) lib/active_record/base.rb:498:in `initialize'
activerecord (3.2.13) lib/active_record/validations.rb:39:in `new'
activerecord (3.2.13) lib/active_record/validations.rb:39:in `create!'
app/controllers/messages_controller.rb:13:in `create'
actionpack (3.2.13) lib/action_controller/metal/implicit_render.rb:4:in `send_action'
actionpack (3.2.13) lib/abstract_controller/base.rb:167:in `process_action'
actionpack (3.2.13) lib/action_controller/metal/rendering.rb:10:in `process_action'
actionpack (3.2.13) lib/abstract_controller/callbacks.rb:18:in `block in process_action'
activesupport (3.2.13) lib/active_support/callbacks.rb:425:in `_run__3805623263237724248__process_action__1465637019578896381__callbacks'
activesupport (3.2.13) lib/active_support/callbacks.rb:405:in `__run_callback'
activesupport (3.2.13) lib/active_support/callbacks.rb:385:in `_run_process_action_callbacks'
activesupport (3.2.13) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (3.2.13) lib/abstract_controller/callbacks.rb:17:in `process_action'
actionpack (3.2.13) lib/action_controller/metal/rescue.rb:29:in `process_action'
actionpack (3.2.13) lib/action_controller/metal/instrumentation.rb:30:in `block in process_action'
activesupport (3.2.13) lib/active_support/notifications.rb:123:in `block in instrument'
activesupport (3.2.13) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (3.2.13) lib/active_support/notifications.rb:123:in `instrument'
actionpack (3.2.13) lib/action_controller/metal/instrumentation.rb:29:in `process_action'
actionpack (3.2.13) lib/action_controller/metal/params_wrapper.rb:207:in `process_action'
activerecord (3.2.13) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
actionpack (3.2.13) lib/abstract_controller/base.rb:121:in `process'
actionpack (3.2.13) lib/abstract_controller/rendering.rb:45:in `process'
actionpack (3.2.13) lib/action_controller/metal.rb:203:in `dispatch'
actionpack (3.2.13) lib/action_controller/metal/rack_delegation.rb:14:in `dispatch'
actionpack (3.2.13) lib/action_controller/metal.rb:246:in `block in action'
actionpack (3.2.13) lib/action_dispatch/routing/route_set.rb:73:in `call'
actionpack (3.2.13) lib/action_dispatch/routing/route_set.rb:73:in `dispatch'
actionpack (3.2.13) 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 (3.2.13) lib/action_dispatch/routing/route_set.rb:612:in `call'
actionpack (3.2.13) 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:35:in `call'
actionpack (3.2.13) lib/action_dispatch/middleware/head.rb:14:in `call'
actionpack (3.2.13) lib/action_dispatch/middleware/params_parser.rb:21:in `call'
actionpack (3.2.13) 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 (3.2.13) lib/action_dispatch/middleware/cookies.rb:341:in `call'
activerecord (3.2.13) lib/active_record/query_cache.rb:64:in `call'
activerecord (3.2.13) lib/active_record/connection_adapters/abstract/connection_pool.rb:479:in `call'
actionpack (3.2.13) lib/action_dispatch/middleware/callbacks.rb:28:in `block in call'
activesupport (3.2.13) lib/active_support/callbacks.rb:405:in `_run__3699448979629391707__call__1119864259513439622__callbacks'
activesupport (3.2.13) lib/active_support/callbacks.rb:405:in `__run_callback'
activesupport (3.2.13) lib/active_support/callbacks.rb:385:in `_run_call_callbacks'
activesupport (3.2.13) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (3.2.13) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
actionpack (3.2.13) lib/action_dispatch/middleware/reloader.rb:65:in `call'
actionpack (3.2.13) lib/action_dispatch/middleware/remote_ip.rb:31:in `call'
actionpack (3.2.13) lib/action_dispatch/middleware/debug_exceptions.rb:16:in `call'
actionpack (3.2.13) lib/action_dispatch/middleware/show_exceptions.rb:56:in `call'
railties (3.2.13) lib/rails/rack/logger.rb:32:in `call_app'
railties (3.2.13) lib/rails/rack/logger.rb:16:in `block in call'
activesupport (3.2.13) lib/active_support/tagged_logging.rb:22:in `tagged'
railties (3.2.13) lib/rails/rack/logger.rb:16:in `call'
actionpack (3.2.13) 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 (3.2.13) lib/active_support/cache/strategy/local_cache.rb:72:in `call'
rack (1.4.5) lib/rack/lock.rb:15:in `call'
actionpack (3.2.13) lib/action_dispatch/middleware/static.rb:63:in `call'
railties (3.2.13) lib/rails/engine.rb:479:in `call'
railties (3.2.13) lib/rails/application.rb:223:in `call'
rack (1.4.5) lib/rack/content_length.rb:14:in `call'
railties (3.2.13) lib/rails/rack/log_tailer.rb:17:in `call'
rack (1.4.5) lib/rack/handler/webrick.rb:59:in `service'
/home/renee/.rvm/rubies/ruby-1.9.3-p374/lib/ruby/1.9.1/webrick/httpserver.rb:138:in `service'
/home/renee/.rvm/rubies/ruby-1.9.3-p374/lib/ruby/1.9.1/webrick/httpserver.rb:94:in `run'
/home/renee/.rvm/rubies/ruby-1.9.3-p374/lib/ruby/1.9.1/webrick/server.rb:191:in `block in start_thread'
答案 0 :(得分：2)
我想你可能想要更接近这一点（未经测试）：
=form_tag(:action => 'create', :controller => 'messages', :method => :get) do
=text_area "message[message]", :size => '40x5'
=hidden_field_tag("message[subject]", "RE:#{@message.subject}")
=hidden_field_tag("message[parent]", @message.id)
=hidden_field_tag("message[receiver]", @message.sender)
=submit_tag 'Reply'