如何在form_for

Question

中使用多個「一對多」嵌套屬性，因爲用戶有很多信用卡，信用卡上有很多地址，我試圖創建一個表單來創建用戶和信用額度卡地址一次全部

relavent型號代碼：

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 

控制器代碼

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

視圖代碼

=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 

所以我遇到的問題是地址字段不顯示。我嘗試將@user.credit_cards.addresses.build添加到控制器，但出現undefined method 'build' for nil錯誤。

Answer 1

在你的控制器，你應該嘗試：

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，因爲@user.credit_cards返回數組...