Rails的多对多令牌字段有帮助

Question

我有这个问题，我的模型不想保存。我有一个标记的标记字段输入。对于令牌输入，我遵循以下指南:http://railscasts.com/episodes/258-token-fields

当我尝试创建一个新的konkurrancer时，得到这个错误:

NoMethodError in Admin/konkurrancersController#create
undefined method `class_name' for nil:NilClass
Rails.root: C:/Rails/konkurranceportalen
Application Trace | Framework Trace | Full Trace
app/models/konkurrancer.rb:15:in `tag_tokens='
app/controllers/admin/konkurrancers_controller.rb:48:in `new'
app/controllers/admin/konkurrancers_controller.rb:48:in `create'
http://pastie.org/1834194
Request
Parameters:
{"utf8"=>"✓",
 "authenticity_token"=>"yo7wcAQl81tx3zZpPP44ENPYzYRZLpgyYKY+HK3yFKM=",
 "konkurrancer"=>{"name"=>"Vind en rejse",
 "banner2"=>"asdasd",
 "tracking"=>"sadasd",
 "vaerdi"=>"12222",
 "tid"=>"1 min",
 "tag_tokens"=>"1",
 "bedom"=>"2",
 "kategori_id"=>"9",
 "form"=>"Nyhedsbrev",
 "partner"=>"Iqmedier",
 "udtraekkes(3i)"=>"30",
 "udtraekkes(2i)"=>"4",
 "udtraekkes(1i)"=>"2011",
 "udtraekkes(4i)"=>"08",
 "udtraekkes(5i)"=>"26",
 "arrangeor"=>"",
 "note"=>""},
 "commit"=>"Opret konkurrence"}

我的konkurrancer模型:

class Konkurrancer < ActiveRecord::Base
attr_accessible :name, :tag_tokens
  has_many :tagsmenus
  has_many :tags, :through => :tagsmenus
attr_reader :tag_tokens
  def tag_tokens=(ids)
    self.tag_ids = ids.split(",")
  end
end

My tag model:

class Tag < ActiveRecord::Base
has_many :tagsmenus
has_many :konkurrancers, :through => :tagsmenus
has_friendly_id :name, :use_slug => true
before_save :assign_cached_slug, :unless => :cached_slug?
protected
  def assign_cached_slug
    self.cached_slug = self.name.gsub(/s+/, '_').gsub(/[^w-]/, '')
  end
end

标签菜单模型:

class Tagsmenu < ActiveRecord::Base
end

我的控制器:

def new
@konkurrancer = Konkurrancer.new  
respond_to do |format|
format.html # new.html.erb
format.xml  { render :xml => @konkurrancer }
end
end
  # POST /konkurrancers
  # POST /konkurrancers.xml
  def create
    @konkurrancer = Konkurrancer.new(params[:konkurrancer])
    respond_to do |format|
      if @konkurrancer.save
        format.html { redirect_to(:admin_konkurrancers, :notice => 'Konkurrancer was successfully created.') }
        format.xml  { render :xml => :admin_konkurrancers, :status => :created, :location => @konkurrancer }
      else
        format.html { render :action => "new" }
        format.xml  { render :xml => @konkurrancer.errors, :status => :unprocessable_entity }
      end
    end
  end

我已经创建了连接表和模型，并将关系添加到标记模型中。

Answer 1

您的模型有一些冲突的语句。首先定义:

attr_accessor ... :tag_tokens

之后有:

attr_reader :tag_tokens

对于第一行来说是不必要的，反之亦然，因为后面会有setter的定义:

def tag_tokens(ids)
  self.tag_ids = ids.split(',')
end

我没有看到tag_ids被定义，因为它不是你表中的一列。您可能应该为tag_tokens删除attr_accessor定义，然后为启动器定义tag_ids方法。

Answer 2

class Tagsmenu < ActiveRecord::Base
  belongs_to :konkurrancer
  belongs_to :tag
end