Rails params問題

Question

我正在嘗試創建一個基本調查應用程序。我試圖用用戶創建的任何答案來創建一個選擇，但出於某種原因，我的問題沒有在我的選擇控制器中設置。

這裏是我的路線：

resources :questions do 
    resources :choices, only: [:create, :destroy] 
    end 

我的觀點：

<h3>Questions:</h3> 
<ul><% @survey.questions.each do |question| %> 
    <li><p><%= question.title %></p></li> 
    <% choice = question.choices.build %> 
    <% if question.single_response == true %> 
    <%= form_for [question, choice] do |f| %> 

      <% question.answers.each do |answer| %> 
      <%= f.radio_button :answer_id, answer.id %> <%= answer.title %><br> 
      <% end %> 
      <%= f.hidden_field :survey_id, value: @survey.id %> 
      <%= f.submit %> 

在我的選擇控制器我set_question方法：

def set_question 
     @question = Question.find(params[:question_id]) 
    end 

，然後我的創建方法：

def create 
    @choice = @question.choices.build(choice_params) 

    respond_to do |format| 
     if @choice.save 
     format.html { redirect_to surveys_path, notice: 'Choice was successfully created.' } 
     format.json { render action: 'show', status: :created, location: @choice } 
     else 
     format.html { render action: 'new' } 
     format.json { render json: @choice.errors, status: :unprocessable_entity } 
     end 
    end 
    end 

這是網絡零類錯誤。

undefined method `choices' for nil:NilClass 

Rails.root: /Users/thomashammond89/SurveyMe 
Application Trace | Framework Trace | Full Trace 

app/controllers/choices_controller.rb:27:in `create' 

Request 

Parameters: 

{"utf8"=>"✓", 
"authenticity_token"=>"XjNNShH6jvTAcz1NQqSBU+a+2exP2STPFnja+yfbinY=", 
"choice"=>{"answer_id"=>"19", 
"survey_id"=>"1", 
"question_id"=>"13"}, 
"commit"=>"Create Choice", 
"question_id"=>"13"} 

在我看來question_id在參數中有。任何想法爲什麼它沒有被設置？

Answer 1

您未在創建操作中定義實例變量@question。嘗試：

@question = Question.find(params[:choice][:question_id])