關聯模型的表單對象中的NoMethodError

Question

我正在構建一個項目管理應用程序。 我的系統就像-一個項目有很多功能，一個功能有很多任務。 並且route.rb被定義為

  resources :projects do
    resources :features do
      resources :tasks
    end
  end

第一個級別，即針對項目的功能對於新功能表單工作正常，但是當我嘗試將新任務表單實現為->

  <%= form_for([@feature, @feature.tasks.build], class: "form-group row") do |form| %>

    <%= form.label :name %>
    <%= form.text_field :name, required:true, class: "form-control" %>

    <%= form.submit class: "btn btn-primary m-2" %>

  <% end %>

現在它顯示錯誤為

這是我的模特->

class Task < ApplicationRecord
  belongs_to :feature
end
class Feature < ApplicationRecord
  belongs_to :project
  has_many :tasks
end

任務控制器看起來像->

class TasksController < ApplicationController  
  before_action :set_feature

  def new
    @task = @feature.tasks.new
  end

  def create
    @task = @feature.tasks.new(task_params)

    if @task.save
       redirect_to project_features_path
    else
      render :new
    end
  end

  def edit
  end

  def update

    if @task.update(task_params)

      redirect_to project_feature_tasks_path
    else
      render :edit
    end

  end

  def complete
    @task.update(completed: true)
    redirect_to project_feature_tasks_path
  end

  def destroy
    @feature.task.destroy
    redirect_to project_feature_tasks_path
  end


  private

  def set_feature
    @feature = Feature.find(params[:feature_id])
  end

  def task_params
    params.require(:task).permit(:name,:completed, :project_id,:feature_id)
  end

end

非常感謝您提供任何幫助-我已經在此錯誤中困擾了幾天。

Answer 1

如果您嘗試運行$ rails routes ，則可以看到當前路線為何無法通過。

                   Prefix Verb   URI Pattern                                                                              Controller#Action
    project_feature_tasks GET    /projects/:project_id/features/:feature_id/tasks(.:format)                               tasks#index
                          POST   /projects/:project_id/features/:feature_id/tasks(.:format)                               tasks#create
 new_project_feature_task GET    /projects/:project_id/features/:feature_id/tasks/new(.:format)                           tasks#new
edit_project_feature_task GET    /projects/:project_id/features/:feature_id/tasks/:id/edit(.:format)                      tasks#edit
     project_feature_task GET    /projects/:project_id/features/:feature_id/tasks/:id(.:format)                           tasks#show
                          PATCH  /projects/:project_id/features/:feature_id/tasks/:id(.:format)                           tasks#update
                          PUT    /projects/:project_id/features/:feature_id/tasks/:id(.:format)                           tasks#update
                          DELETE /projects/:project_id/features/:feature_id/tasks/:id(.:format)    

您必須致電：

form_for([@project, @feature, @feature.tasks.build], ...) do |form|

一個更好的主意是使路線嵌套。 您可以通過使用shallow選項來做到這一點：

resources :projects do
  resources :features, shallow: true do
    resources :tasks
  end
end

或者，您可以這樣做，如果出於某種原因想要保留嵌套功能的成員路線（顯示，編輯，更新，銷毀）：

resources :projects do
  resources :features
end

resources :features, only: [] do
  resources :tasks
end