Ruby on rails - nil:NilClass 的未定义方法“each”

Question

每次我提交表单时都会收到此错误：undefined method `each' for nil:NilClass。如果一切正确，我可以毫无问题地提交表格，但是当缺少一件事时，它就会给我错误。该错误将我发送到此行：

views/users/new.html.haml

- @subscriptions.each do |fbs|
  = fb.radio_button :subscription_id, fbs.id, class: 'radiobtn', required: true

controllers/users_controller.rb

def new
  @user = Users::Business.new
  @subscriptions = Businesses::Subscription.all
end

def create
  @user = Users::Business.new(user_params)

  if @user.save
    sign_in(@user)
  else
    render :new
  end
end

Answer 1

它正在发生，因为该模型没有任何价值。您可以将数据检查到 rails console 喜欢，

$rails console
> Businesses::Subscription.count

如果您发现没有数据，那么您可以编写一个 if ... end 块来检查空值并处理它。

Answer 2

也在创建操作中分配订阅：

before_filter :set_subscriptions, only: %w(new create) #for edit and update if needed

private
def set_subscriptions
  @subscriptions = Businesses::Subscription.all
end

或者保存失败后直接在create动作中添加@subscriptions = Businesses::Subscription.all，重新渲染new表单

Ruby on rails - nil:NilClass 的未定义方法“each”

Ruby on rails - undefined method `each' for nil:NilClass

ruby

methods

haml

ruby-on-rails