如何在rails中处理这种类型的多级表单

Question

我在轨道3.1.我有以下型号

    class Tool < ActiveRecord::Base
        has_many :comments
    end

    class Comment < ActiveRecord::Base
        belongs_to :tool
        has_many :relationships
        has_many :advantages, :through => :relationships, :source => :resource, :source_type => 'Advantage'
        has_many :disadvantages, :through => :relationships, :source => :resource, :source_type => 'Disadvantage'

    end

    class Relationship < ActiveRecord::Base
        belongs_to :comment
        belongs_to :resource, :polymorphic => true
    end

    class Disadvantage < ActiveRecord::Base
        has_many :relationships, :as => :resource
        has_many :comments, :through => :relationships
    end

    class Advantage < ActiveRecord::Base
        has_many :relationships, :as => :resource
        has_many :comments, :through => :relationships
    end

简而言之,A Tool有很多comments.转换Comment与Advantages和相关联Disadvantages.所以在我的tool/show页面中,我会列出所有评论.

但是如果我必须在工具页面上添加注释,那么会有一个表单有一个textarea用于注释,两个multi select list boxes表示优点和缺点.

如果用户想要从现有的adv/disadv中选择,用户可以从列表框中选择,或者如果用户想要添加新的adv/disadv,他可以输入并添加它,这样就可以了.通过ajax调用保存,新的adv/disadv被添加到列表框中.我该怎么做？

Answer 1

您正在寻找的是"嵌套表格" - 它们非常简单易用.

在您的Gemfile中添加:

gem "nested_form"

1)在你的main_model中,你将包含一个调用accepts_nested_attributes_for :nested_model

class MainModel
  accepts_nested_attributes_for :nested_model
end

2)在main_model而不是form_for()的视图中,您将在顶部调用nested_form_for()

= nested_form_for(@main_model) do |f|
   ...

检查该方法的Rails页面,它有一些有趣的选项,例如:reject_if,:allow_destroy,...

3)在main_model的视图中,当你想显示嵌套模型的子表单时,你会做

= f.fields_for :nested_model   # replace with your other model name

然后它将使用_form partial作为nested_model并将其嵌入到main_model的视图中

奇迹般有效!

查看这些RailsCast.com剧集,其中深入介绍了嵌套表格:

http://railscasts.com/episodes/196-nested-model-form-part-1

http://railscasts.com/episodes/197-nested-model-form-part-2

希望这可以帮助