Ruby on rails Rails 3-未定义的方法'map'；for nil:NilClass用于我自己的验证

我遇到了一个很奇怪的问题。我有

时间表

模型，并尝试编写自定义验证。所以，现在我只是尝试为字段添加测试错误，以确保一切正常。但它不起作用。所以，我尝试更新时间表模型的对象，但当我不使用我的测试自定义验证时，一切都很完美。否则我会得到这样的错误：

NoMethodError in Timetables#update 

undefined method `map' for nil:NilClass

32: 
33:       <div class="controls">
34:         <%= f.select( :curriculum_id,                                                           
35:                       options_for_select( @subjects_with_curriculums,
36:                                           @tt.curriculum_id ),
37:                       { :include_blank => true }) %>
38:       </div>

NoMethodError在时间表中#更新
nil:NilClass的未定义方法“map”
32: 
33:       
34：正确}）%>
38:       

这是我的模型：

# == Schema Information
#
# Table name: timetables
#
#  id                  :integer         not null, primary key
#  curriculum_id       :integer
#  school_class_id     :integer
#  tt_day_of_week      :string(255)
#  tt_number_of_lesson :integer
#  tt_room             :string(255)
#  tt_type             :string(255)
#  created_at          :datetime        not null
#  updated_at          :datetime        not null
#

class Timetable < ActiveRecord::Base
  belongs_to :curriculum
  belongs_to :school_class

  has_many :lessons

  validates :school_class_id, :presence => { :message => "should exist" }

  validates :tt_day_of_week,
              :presence  => true,
              :inclusion => { :in => %w(Mon Tue Wed Thu Fri) }

  validates :tt_number_of_lesson,
              :presence => true,
              :inclusion => {
                              :in => 1..9,
                              :message => "should have 1..9 symbols"
                            }

  validates :tt_room,
              :length => {
                           :maximum => 3,
                           :message => "should have 3 symbols"
                         },
              :allow_blank => true

  validates :tt_type,
              :inclusion => { :in => ["Primary lesson", "Extra"] },
              :allow_blank => true

  validate :test

  def test
    errors.add(:tt_number_of_lesson, "test")
  end
end 

#==架构信息
#
#表名：时间表
#
#id:整数不为空，主键
#课程号：整数
#学校\班级\ id:整数
#每周的tt天：字符串（255）
#第一课：整数
#tt_房间：字符串（255）
#tt_类型：字符串（255）
#创建时间：datetime非空
#更新时间：datetime非空
#
课程时间表{:message=>“应该存在”}
验证：tt_day_of_week，
：presence=>true，
：inclusion=>{:in=>%w（周一周二周三周四周五）}
验证：TTU课程的TTU编号，
：presence=>true，
：包含=>{
：in=>1..9，
：message=>“应该有1..9个符号”
}
验证：tt_室，
：长度=>{
：最大=>3，
：message=>“应该有3个符号”
},
：allow_blank=>true
验证：tt_类型，
：inclusion=>{:in=>[“初级课程”，“额外”]}，
：allow_blank=>true
验证：测试
def测试
错误。添加（：tt_课程编号“测试”）
结束
结束

我的控制器：

# encoding: UTF-8
class TimetablesController < ApplicationController
  ...

  def edit
    @types_of_lesson = collect_types_of_lesson
    @tt = Timetable.find( params[:id] )
    @subjects_with_curriculums = collect_subjects_with_curriculums( @tt.school_class )
  end

  def update
    @tt = Timetable.find( params[:id] )

    if @tt.update_attributes( params[:timetable] )
      flash[:success] = "Расписание успешно обновлено!"
      redirect_to timetables_path
    else
      flash.now[:error] = @tt.errors.full_messages.to_sentence :last_word_connector => ", ",
                                                               :two_words_connector => ", "
      render 'edit'
    end
  end

  private
    # Collecting subjects names for school class and curriculum_id for each subject.
    def collect_subjects_with_curriculums( school_class )
      subjects = school_class.curriculums.collect do |c|
        [ c.qualification.subject.subject_name, c.id  ]
      end
    end

    def timetable_for_class_with_existance_data( school_class )
      return [] if Timetable.all.empty?

      Timetable.select do |t|
        ( t.school_class.class_code == school_class.class_code ) and
        not ( t.tt_room.blank? ) and not ( t.tt_type.blank? ) and
        not ( t.curriculum_id.nil? )
      end.to_a
    end

    # Return for school class it's timetable.
    def timetable_for_class( school_class )
      Timetable.select{|t| t.school_class.class_code == school_class.class_code }.to_a
    end

    def subjects_of_class( school_class )
      subjects = school_class.curriculums.collect do |c|
        c.qualification.subject.subject_name
      end
    end

    # Return sorted by number of lesson tometable for one day.
    def sorted_timetable_for_day( timetable, day )
      timetable.select{ |t| t.tt_day_of_week == day }
               .sort_by{ |e| e[:tt_number_of_lesson] }
    end

    # Return russian name for type of lesson.
    def collect_types_of_lesson
      [ ["Обязательно занятие", "Primary lesson"], ["Электив", "Extra"] ]
    end

    # Check if timetable already has been created for school class.
    def timetable_exists?( school_class )
      not timetable_for_class( school_class ).empty?
    end
end

render 'edit'

编码：UTF-8 类TimetablesController<应用程序控制器 ... 定义编辑 @课程类型=收集课程类型 @tt=时间表。查找（参数[：id]） @课程科目=收集课程科目（@tt.school\u class） 结束 def更新 @tt=时间表。查找（参数[：id]） if@tt.update_属性（参数[：时间表]） flash[：success]=“аааааааааааааааа 将\u重定向到时间表\u路径 其他的 flash.now[：error]=@tt.errors.full_messages.to_句子：last_word_connector=>“，”， ：两个单词\u连接器=>“，” 渲染“编辑” 结束 结束 私有的 #收集学校班级的科目名称和每个科目的课程id。 def收集课程中的科目（学校课程） 科目=学校|班级.课程.收集do | c| [c.qualification.subject.subject_姓名，c.id] 结束 结束 带有现有数据的班级的def时间表（学校班级） 如果timeline.all.empty为空，返回[]？ 时间表。选择do | t| （t.school_class.class_code==school_class.class_code）和 非（t.tt_房间空白？）和非（t.tt_类型空白？）和 不是（t.课程\ id.无？） 完 结束 #上课时间到了。 def课程时间表（学校课程） 时间表。选择{t | t.school|u class.class_code==school|u class.class_code}。到 结束 def课程（学校课程） 科目=学校|班级.课程.收集do | c| c、 资格、科目、科目名称 结束 结束 #返回按一天可编辑的课程数排序的结果。 def分拣的日时间表（时间表，日） 时间表。选择{t | t.tt_day_of_week==day} .sort_by{e|e[：tt_number_of_lesson]} 结束 #返回课程类型的俄语名称。 def收集课程的类型 [“初级课程”]、[“额外课程”] 结束 #检查是否已经为学校班级创建了时间表。 是否存在def时间表？（学校/班级） 没有上课时间表（学校课）。空吗？ 结束 结束 我的看法

<%= form_for @tt, :html => {:class => "form-horizontal"} do |f| %>
  <%= field_set_tag do %>

    <%= f.hidden_field :tt_number_of_lesson %>
    <%= f.hidden_field :tt_day_of_week %>
    <%= f.hidden_field :school_class_id %>

    <div class="control-group">
       <%= f.label :tt_day_of_week, "Day of the week", :class => "control-label" %>

       <div class="controls">
         <%= content_tag( :span, translate_day_of_week( @tt.tt_day_of_week ),
                          :class =>"input-xlarge uneditable-input span2" ) %>
       </div>
    </div>

    <div class="control-group">
       <%= f.label :tt_number_of_lesson, "Number of lesson", :class => "control-label" %>

       <div class="controls">
         <%= content_tag( :span, @tt.tt_number_of_lesson,
                          :class =>"input-xlarge uneditable-input span1" ) %>
       </div>
    </div>

    <hr/>

    <div class="control-group">
      <%= f.label :curriculum_id, "Type of subject", :class => "control-label" %>

      <div class="controls">
        <%= f.select( :curriculum_id,                                                           
                      options_for_select( @subjects_with_curriculums,
                                          @tt.curriculum_id ),
                      { :include_blank => true }) %>
      </div>
    </div>

    <div class="control-group">
      <%= f.label :tt_room, "Code of the room", :class => "control-label" %>

      <div class="controls">
        <%= f.text_field :tt_room, :class => "span2", :maxlength => 3 %>
      </div>
    </div>

    <div class="control-group">
      <%= f.label :tt_type, "Type of the lesson", :class => "control-label" %>

      <div class="controls">
        <%= f.select( :tt_type,                                                           
                      options_for_select( @types_of_lesson,
                                          @tt.tt_type ),
                      { :include_blank => true }) %>
      </div>
    </div>

    <%= f.submit "Update", :class => "btn btn-large btn-warning" %>
  <% end %>
<% end %>  

{:class=>“水平形式”}do | f |%>
“控制标签”%>
“输入xlarge不可编辑输入span2”）%%>
“控制标签”%>
“输入xlarge不可编辑的输入span1”）%%>

“控制标签”%>
真}）%%>
“控制标签”%>
“span2”，：maxlength=>3%>
“控制标签”%>
真}）%%>
“btn btn大型btn警告”%>

当我删除：

<div class="control-group">
  <%= f.label :curriculum_id, "Type of subject", :class => "control-label" %>

  <div class="controls">
    <%= f.select( :curriculum_id,                                                           
                  options_for_select( @subjects_with_curriculums,
                                      @tt.curriculum_id ),
                  { :include_blank => true }) %>
  </div>
</div>

<div class="control-group">
  <%= f.label :tt_type, "Type of the lesson", :class => "control-label" %>

  <div class="controls">
    <%= f.select( :tt_type,                                                           
                  options_for_select( @types_of_lesson,
                                      @tt.tt_type ),
                  { :include_blank => true }) %>
  </div>
</div>

“控制标签”%>
真}）%%>
“控制标签”%>
真}）%%>

---

我可以查看我的测试错误。我想不出发生了什么事。

你在

更新中这样说
控制器：

# encoding: UTF-8
class TimetablesController < ApplicationController
  ...

  def edit
    @types_of_lesson = collect_types_of_lesson
    @tt = Timetable.find( params[:id] )
    @subjects_with_curriculums = collect_subjects_with_curriculums( @tt.school_class )
  end

  def update
    @tt = Timetable.find( params[:id] )

    if @tt.update_attributes( params[:timetable] )
      flash[:success] = "Расписание успешно обновлено!"
      redirect_to timetables_path
    else
      flash.now[:error] = @tt.errors.full_messages.to_sentence :last_word_connector => ", ",
                                                               :two_words_connector => ", "
      render 'edit'
    end
  end

  private
    # Collecting subjects names for school class and curriculum_id for each subject.
    def collect_subjects_with_curriculums( school_class )
      subjects = school_class.curriculums.collect do |c|
        [ c.qualification.subject.subject_name, c.id  ]
      end
    end

    def timetable_for_class_with_existance_data( school_class )
      return [] if Timetable.all.empty?

      Timetable.select do |t|
        ( t.school_class.class_code == school_class.class_code ) and
        not ( t.tt_room.blank? ) and not ( t.tt_type.blank? ) and
        not ( t.curriculum_id.nil? )
      end.to_a
    end

    # Return for school class it's timetable.
    def timetable_for_class( school_class )
      Timetable.select{|t| t.school_class.class_code == school_class.class_code }.to_a
    end

    def subjects_of_class( school_class )
      subjects = school_class.curriculums.collect do |c|
        c.qualification.subject.subject_name
      end
    end

    # Return sorted by number of lesson tometable for one day.
    def sorted_timetable_for_day( timetable, day )
      timetable.select{ |t| t.tt_day_of_week == day }
               .sort_by{ |e| e[:tt_number_of_lesson] }
    end

    # Return russian name for type of lesson.
    def collect_types_of_lesson
      [ ["Обязательно занятие", "Primary lesson"], ["Электив", "Extra"] ]
    end

    # Check if timetable already has been created for school class.
    def timetable_exists?( school_class )
      not timetable_for_class( school_class ).empty?
    end
end

render 'edit'

这只是告诉Rails呈现编辑模板，它不运行与
edit
控制器关联的任何代码，它只是在当前上下文中呈现
edit.html.erb

从：

2.2.2呈现动作视图

[关于
render'x'
，
render:x
，和
render:action=>：x
相同的一些东西…]

将
渲染
与
：操作
一起使用，经常会使Rails新手感到困惑。指定的操作用于确定要渲染的视图，但Rails不会在控制器中运行该操作的任何代码。在调用
render
之前，必须在当前操作中设置视图中需要的任何实例变量

特别注意最后一句话