Question

在我的应用中，用户填写表单并创建父类 - 成本

稍后，我希望用户能够返回添加关联类 - Cost Dependencies。

因此用户可以导航到/ costs / 3 / cost_dependencies / new

当我尝试在我的视图中引用@cost时，我收到了一个nil类错误，所以我添加了@cost=Cost.find(param[:id])来在我的控制器中访问它。

现在我收到Couldn't find Cost with id=错误

它只是空白。

Answer 1

假设您已设置嵌套路线，例如：

resources :costs do
  resources :cost_dependencies
end

然后，费用ID将以params[:cost_id]显示，您可以通过运行rake routes进行确认。你应该看到如下内容：

              cost_cost_dependencies GET      /costs/:cost_id/cost_dependencies(.:format)                                        cost_dependencies#index
                                     POST     /costs/:cost_id/cost_dependencies(.:format)                                        cost_dependencies#create
            new_cost_cost_dependency GET      /costs/:cost_id/cost_dependencies/new(.:format)                                    cost_dependencies#new
           edit_cost_cost_dependency GET      /costs/:cost_id/cost_dependencies/:id/edit(.:format)                               cost_dependencies#edit
                cost_cost_dependency GET      /costs/:cost_id/cost_dependencies/:id(.:format)                                    cost_dependencies#show
                                     PATCH    /costs/:cost_id/cost_dependencies/:id(.:format)                                    cost_dependencies#update
                                     PUT      /costs/:cost_id/cost_dependencies/:id(.:format)                                    cost_dependencies#update
                                     DELETE   /costs/:cost_id/cost_dependencies/:id(.:format)                                    cost_dependencies#destroy
                               costs GET      /costs(.:format)                                                                   costs#index
                                     POST     /costs(.:format)                                                                   costs#create
                            new_cost GET      /costs/new(.:format)                                                               costs#new
                           edit_cost GET      /costs/:id/edit(.:format)                                                          costs#edit
                                cost GET      /costs/:id(.:format)                                                               costs#show
                                     PATCH    /costs/:id(.:format)                                                               costs#update
                                     PUT      /costs/:id(.:format)                                                               costs#update
                                     DELETE   /costs/:id(.:format)                                                               costs#destroy

因此，在您的控制器中使用以下内容：

@cost = Cost.find(param[:cost_id])

Rails：在创建父级之后创建belongs_to关联类

1 个答案: