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花了最後一天半的時間，通過SO這裏的精彩線索和在線閱讀其他東西，我仍然無法抓住解決方案以及這些移動部件如何一起工作。如何通過關聯創建一個刪除has_many的link_to刪除操作？
我通過CountyTownshipRangeSurvey獲得了County和TownshipRange之間的多對多關係。這種關係通過嵌套資源在路線文件中指出。
我希望用戶能夠刪除兩條記錄之間的關聯，但是我遇到的問題是TownshipRange索引頁上的刪除鏈接只接受township_range id值而不是關聯的縣id值。請注意，在查看索引頁（其中包含刪除鏈接）時，顯示正確的縣id參數。
我該如何允許？
我的直覺是我需要在兩個地方做出改變。首先，路由文件，因此它會接受縣編號，第二，到視圖中的link_to。
作爲一個後續問題......我意識到我試圖將功能放入township_ranges_controller。這是問題的一部分嗎？我能否更好地將這一功能轉移到專門用於創建「直通表」關聯的單獨控制器中？
謝謝大家的寶貴見解！如果您需要更多代碼片段，請告訴我！
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中的相關部分（擴展20161124）
resources :states, shallow: true do
resources :counties do
resources :township_ranges do
resources :sections
end
end
end
導軌路由指示產生的路線不查找相關聯的縣/：ID爲刪除操作。
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
它會尋找完整的路線DELETE counties/:county_id/township_range/:id/如果我本身隔離嵌套這樣
resources :counties do
resources :township_ranges
end
但是，保持縣被嵌套在狀態，這不是我後。 ..
township_range/index.html.erb
<td><%= link_to 'Destroy', township_range, method: :delete,
data: { confirm: "Delete #{township_range.township}
#{township_range.range} ?" } %></td>
發展。登錄（與鏈接更新由@Wish區的要求）
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 %>
路線應該是township_range（ID：township_range，COUNTRY_ID ：country）和控制器中可以找到Country.find（params [：country_id]） –