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花了最后一天半的时间，通过SO这里的精彩线索和在线阅读其他东西，我仍然无法抓住解决方案以及这些移动部件如何一起工作。如何通过关联创建一个删除has_many的link_to删除操作？
我通过CountyTownshipRangeSurvey获得了County和TownshipRange之间的多对多关系。这种关系通过嵌套资源在路线文件中指出。
我希望用户能够删除两条记录之间的关联，但是我遇到的问题是TownshipRange索引页上的删除链接只接受township_range id值而不是关联的县id值。请注意，在查看索引页（其中包含删除链接）时，显示正确的县id参数。
我该如何允许？
我的直觉是我需要在两个地方做出改变。首先，路由文件，因此它会接受县编号，第二，到视图中的link_to。
作为一个后续问题......我意识到我试图将功能放入township_ranges_controller。这是问题的一部分吗？我能否更好地将这一功能转移到专门用于创建“直通表”关联的单独控制器中？
谢谢大家的宝贵见解！如果您需要更多代码片段，请告诉我！
模型county.rb
class County < ApplicationRecord
has_many :township_ranges, through: :county_township_range_surveys
has_many :county_township_range_surveys
...
end
模型township_range.rb
class TownshipRange < ApplicationRecord
has_many :counties, through: :county_township_range_surveys
has_many :county_township_range_surveys
...
end
模型county_township_range_survey.rb
class CountyTownshipRangeSurvey < ApplicationRecord
belongs_to :county
belongs_to :township_range
...
end
控制器township_ranges_controller.rb
routes.rb中的相关部分（扩展20161124）
resources :states, shallow: true do
resources :counties do
resources :township_ranges do
resources :sections
end
end
end
导轨路由指示产生的路线不查找相关联的县/：ID为删除操作。
township_ranges GET /counties/:id/township_ranges(.:format) township_ranges#index
POST /counties/:id/township_ranges(.:format) township_ranges#create
new_township_range GET /counties/:id/township_ranges/new(.:format) township_ranges#new
edit_township_range GET /township_ranges/:id/edit(.:format) township_ranges#edit
township_range GET /township_ranges/:id(.:format) township_ranges#show
PATCH /township_ranges/:id(.:format) township_ranges#update
PUT /township_ranges/:id(.:format) township_ranges#update
DELETE /township_ranges/:id(.:format) township_ranges#destroy
它会寻找完整的路线DELETE counties/:county_id/township_range/:id/如果我本身隔离嵌套这样
resources :counties do
resources :township_ranges
end
但是，保持县被嵌套在状态，这不是我后。 ..
township_range/index.html.erb
<td><%= link_to 'Destroy', township_range, method: :delete,
data: { confirm: "Delete #{township_range.township}
#{township_range.range} ?" } %></td>
发展。登录（与链接更新由@Wish区的要求）
Started GET "/counties/25/township_ranges" for 127.0.0.1 at 2016-11-23 15:23:20 -0600
Processing by TownshipRangesController#index as HTML
Parameters: {"id"=>"25"}
[1m[36mCounty Load (0.1ms)[0m [1m[34mSELECT "counties".* FROM "counties" WHERE "counties"."id" = ? LIMIT ?[0m [["id", 25], ["LIMIT", 1]]
Rendering township_ranges/index.html.erb within layouts/application
[1m[36mTownshipRange Load (34.5ms)[0m [1m[34mSELECT "township_ranges".* FROM "township_ranges" INNER JOIN "county_township_range_surveys" ON "township_ranges"."id" = "county_township_range_surveys"."township_range_id" WHERE "county_township_range_surveys"."county_id" = ?[0m [["county_id", 25]]
Rendered township_ranges/index.html.erb within layouts/application (72.6ms)
Completed 500 Internal Server Error in 113ms (ActiveRecord: 35.2ms)
ActionView::Template::Error (No route matches {:action=>"show", :controller=>"township_ranges", :county_id=>#<County id: 25, name: "comanche", abbreviation: nil, state_id: 35, created_at: "2016-11-22 16:24:52", updated_at: "2016-11-22 16:24:52">, :id=>nil} missing required keys: [:id]):
22: <td><%= link_to 'Edit', edit_township_range_path(township_range) %></td>
23: <%# QUESTION: Do I need to modify the link here so it somehow takes in the county id param? %>
24: <%# NOTE: This will likely also require some sort of customization to the routes file so that the county_id is passed as a param %>
25: <td><%= link_to 'Destroy', township_range_path(id: @township_range, county_id: @county), method: :delete,
26: data: { confirm: "Delete #{township_range.township} #{township_range.range} ?" } %></td>
27: </tr>
28: <% end %>
路线应该是township_range（ID：township_range，COUNTRY_ID ：country）和控制器中可以找到Country.find（params [：country_id]） –