ruby-on-rails - 未定义的方法 `build' 为 nil :NilClass rails

Question

我认为正在发生的是我认为的 :pledge 属性(:amount 和 :frequency)没有传递给 Controller ​​中的新操作。另外，我知道我的质押属性没有保存，这可能是因为在调用 @user 时 promise_id 为零。

新的.html.erb

<%= form_for @user, url: pledge_path, controller: 'user', action:     'create', method: 'post' do |f| %>
  <%= f.label :user_name %>
  <%= f.text_area :user_name %>
  <%= f.label :email %>
  <%= f.text_area :email%>
  <%= f.label :address %>
  <%= f.text_area :address %>
  <%= f.fields_for(:pledge) do |b| %>
    <%= b.label :amount %>
    <%= b.text_area :amount %>
    <%= b.label :frequency %>
    <%= b.text_area :frequency %>
    <%= b.submit 'I also want o pledge' %>
  <% end %>
<%= f.submit 'I just want to sumbit my info' %>

<% end %>

promise 文件

class Pledge < ActiveRecord::Base
  belongs_to :user
  validates_presence_of :user

end

用户名

class User < ActiveRecord::Base
  has_many :pledges, foreign_key: "pledge_id"
   accepts_nested_attributes_for :pledges
   attr_accessor :pledges

end

模式文件

ActiveRecord::Schema.define(version: 20150318161827) do

create_table "pledges", force: :cascade do |t|
  t.integer "frequency"
  t.float   "amount"
  t.integer "user_id"
end

add_index "pledges", ["user_id"], name: "index_pledges_on_user_id"

create_table "users", force: :cascade do |t|
  t.string  "user_name"
  t.string  "email"
  t.string  "address"
  t.integer "pledge_id"
end

end

用户 Controller .rb

class UserController < ApplicationController
def new
    @user = User.new
    @user.pledges.build 
end

def create
    if params[:commit] == 'I just want to sumbit my info'
        User.create(user_params)

    elsif
        @pledge = Pledge.new(params[:pledge])
        @pledge.save
        @user = User.create(pledge_params)  
    end
    redirect_to thank_you_path

end
def pledge_params
    params.require(:user).permit(:email, :user_name, :address,
                                pledge_attributes: [:id, :amount, :frequency])
end

def user_params
    params.require(:user).permit(:email, :user_name, :address)
end
end

在此先感谢您的任何建议!

Answer 1

信息来自 here在像你这样的情况下对我很有帮助。

所以在Sontya的代码中你需要改变@user.pledges.build至 @user.build_pledges .

虽然，我认为你解决了你的问题，但我做这个答案是为了帮助任何将搜索此信息的人。