如何在 form_for 中使用多个“一对多”嵌套属性

Question

鉴于一个用户有很多信用卡并且一张信用卡有很多地址，我正在尝试创建一个表单来同时创建一个用户和信用卡的地址

相关型号代码：

class User < ActiveRecord::Base
  has_many :credit_cards
  accepts_nested_attributes_for :credit_cards
end

class CreditCard < ActiveRecord::Base
  has_many :addresses
  accepts_nested_attributes_for :addresses
end

控制器代码

def new
  @user = User.new
  @user.credit_cards.build
end

查看代码

=form_for @user, :url => users_path do |u|
  =u.label :first_name, "Name"
  =u.text_field :first_name
    -u.fields_for :credit_cards do |cc|
      =cc.label :name_on_card, "Name on Card"
      =cc.text_field :name_on_card
      -cc.fields_for :address do |address|
        =address.label :address, "Address"
        =address.text_field :address1

所以我遇到的问题是地址字段不显示。我尝试将@user.credit_cards.addresses.build 添加到控制器，但出现undefined method 'build' for nil 错误。

Answer 1

在您的控制器中，您应该尝试：

cc = @user.credit_cards.build
cc.adrresses.build

或

@user.credit_cards.build
@user.credit_cards.each{|cc| cc.addresses.build }

@user.credit_cards.addresses.build 不起作用，因为@user.credit_cards 返回一个数组...