Accept_nested_attributes_for 部分的 AJAX 更新

Question

我目前的工作环境是Rails2.3.8（由于种种原因我的公司还没有迁移到Rails 3）。 我正在尝试通过 AJAX 调用更新多模型表单的元素 - 这个想法是根据用户如何选择或填写其他字段来替换某些下拉列表。

我之前曾设法通过使用基于非表单的部分来实现此工作 - 我现在遇到的问题是当部分基于 form_for 和 fields_for 时重现选择下拉列表的 AJAX 更新。

抱歉，下面的文字墙 - 我已尝试尽可能地减少它（代码本身确实可以在我的测试站点上运行）。

如何在 Outbreak 控制器中生成表单构建器元素，然后将其传递到部分类别以取代 event_form？

任何指针都会很棒：D

模型

class Outbreak < ActiveRecord::Base
        has_many :incidents, :dependent => :destroy
        has_many :locations, :through => :incidents

     accepts_nested_attributes_for :locations, :allow_destroy => true, :reject_if => :all_blank
     accepts_nested_attributes_for :incidents, :allow_destroy => true, :reject_if => :all_blank
end

class Incident < ActiveRecord::Base
    belongs_to :outbreak
    belongs_to :location
    belongs_to :category
    belongs_to :subcategory
    belongs_to :subtype

end

class Location < ActiveRecord::Base
    has_many :incidents, :dependent => :destroy
     has_many :outbreaks, :thorugh => incidents
end

视图

_form

<% form_for(@outbreak, :html => {:multipart => true}) do |form| %>

  <%= render :partial => 'outbreak_type_select', :locals => {:outbreak_types => @outbreak_types, :f => form } %>
   <% form.fields_for :incidents do |incident_form| %>
      <%= render :partial => 'category_select', :locals => {:categories => @categories, :incident_form => incident_form} %>
      <%= render :partial => 'subcategory_select', :locals => { :subcategories => @subcategories, :incident_form => incident_form } %>

   <% end %>
<% end %>

_outbreak_type_select

<% with_str = "'outbreak_type=' + value " %>
<% if @outbreak.id %>
<% with_str << "+ '&id=' + #{outbreak.id}" %>
<% end %>
<%= f.collection_select(:outbreak_type, @outbreak_types, :property_value, :property_value, {}, {:onchange => "#{remote_function(:url  => { :action => "update_select_menus"}, :with => with_str)}"}  ) %>

_category_select

调用 update_select_menus 后如何生成 event_form

<%= incident_form.collection_select( :category_id, @categories, :id, :name, {:prompt   => "Select a category"}, {:onchange => "#{remote_function(:url  => { :action => "update_subcategory"}, :with => "'category_id='+value")}"}) %>

RJS

   begin
    page.replace_html 'outbreak_transmission_div', :partial => 'outbreaks/transmission_mode_select', :locals => {:transmission_modes => @transmission_modes }
   rescue
    page.insert_html :bottom, 'ajax_error', '<p>Error :: transmission modes update select</p>'
    page.show 'ajax_error'
   end
   begin
    page.replace_html 'incident_category_select', :partial => 'outbreaks/category_select', :locals => { :categories => @categories }  
   rescue
    page.insert_html :bottom, 'ajax_error', '<p>Error :: incident category update select</p>'
    page.show 'ajax_error'
   end

控制器

爆发

    def new
        @outbreak = Outbreak.new

        @outbreak.incidents.build
        @outbreak.locations.build

        #just the contents for the dropdowns
        @categories = Category.find(:all, :conditions => {:outbreak_type => "FOODBORNE"}, :order => "outbreak_type ASC")
        @subcategories = Subcategory.find(:all, :order => "category_id ASC")

    end

   def update_select_menus
      @outbreak_type = params[:outbreak_type].strip
      if params[:id]
        @outbreak = Outbreak.find(params[:id])
      else
        @outbreak = Outbreak.new
        @outbreak.incidents.build
              @outbreak.locations.build       
      end

      if @outbreak_type == "FOODBORNE"
          ob_type_query = "OUTBREAKS:TRANSMISSION_MODE:" << @outbreak_type
          @transmission_modes = Property.find(:all, :conditions => {:field => ob_type_query})

          ob_type_query = "INVESTIGATIONS:CATEGORY:" << @outbreak_type
          @sample_types = Property.find(:all, :conditions => {:field => ob_type_query})
          @categories = Category.find(:all, :conditions => { :outbreak_type => "FOODBORNE"})
          @subcategories = Subcategory.find(:all, :conditions => { :category_id => @categories.first.id})
          @subtypes = Subtype.find(:all, :conditions => { :subcategory_id => @subcategories.first.id})
      elsif @outbreak_type == "NON-FOODBORNE"
          ob_type_query = "OUTBREAKS:TRANSMISSION_MODE:" << @outbreak_type
          @transmission_modes = Property.find(:all, :conditions => {:field => ob_type_query})

          ob_type_query = "INVESTIGATIONS:CATEGORY:" << @outbreak_type
          @sample_types = Property.find(:all, :conditions => {:field => ob_type_query})
          @categories = Category.find(:all, :conditions => { :outbreak_type => "NON-FOODBORNE"})
          @subcategories = Subcategory.find(:all, :conditions => { :category_id => @categories.first.id})
          @subtypes = Subtype.find(:all, :conditions => { :subcategory_id => @subcategories.first.id})
     end

     respond_to do |format|
          format.html
          format.js
      end

  end

Answer 1

找到了基于 http://www.treibstofff.de/2009/07/12/ruby-on-rails-23-nested-attributes-with-ajax-support/

这可能应该放在爆发助手中（在爆发中控制器 atm)

    def update_select_menus
      @outbreak_type = params[:outbreak_type].strip
      #next_child_index will only be used if 
      @next_child_index ? params[:next_child_index] : 0
      if params[:id]
        @outbreak = Outbreak.find(params[:id])
      else
        @outbreak = Outbreak.new
        @outbreak.risks.build
        @outbreak.incidents.build
        @outbreak.locations.build

      end

      if @outbreak_type == "FOODBORNE"
          ob_type_query = "OUTBREAKS:TRANSMISSION_MODE:" << @outbreak_type
          @transmission_modes = Property.find(:all, :conditions => {:field => ob_type_query})

          ob_type_query = "INVESTIGATIONS:CATEGORY:" << @outbreak_type

          @sample_types = Property.find(:all, :conditions => {:field => ob_type_query})
          @categories = Category.find(:all, :conditions => { :outbreak_type => "FOODBORNE"})
          @subcategories = Subcategory.find(:all, :conditions => { :category_id => @categories.first.id})
          @subtypes = Subtype.find(:all, :conditions => { :subcategory_id => @subcategories.first.id})


      elsif @outbreak_type == "NON-FOODBORNE"
          ob_type_query = "OUTBREAKS:TRANSMISSION_MODE:" << @outbreak_type
          @transmission_modes = Property.find(:all, :conditions => {:field => ob_type_query})

          ob_type_query = "INVESTIGATIONS:CATEGORY:" << @outbreak_type

          @sample_types = Property.find(:all, :conditions => {:field => ob_type_query})
          @categories = Category.find(:all, :conditions => { :outbreak_type => "NON-FOODBORNE"})
          @subcategories = Subcategory.find(:all, :conditions => { :category_id => @categories.first.id})
          @subtypes = Subtype.find(:all, :conditions => { :subcategory_id => @subcategories.first.id})
     end

     @pathogen_types = Property.find(:all, :conditions => {:field => "PATHOGENS:CATEGORY"})
     @outbreak_types = Property.find(:all, :conditions => {:field => "OUTBREAKS:OUTBREAK_TYPE"} )


     render :update do |page|
         page.replace 'outbreak_transmission_div', :partial => 'transmission_mode_select_update'
         page.replace 'incident_category_select', :partial => 'incident_category_select_update'
         page.replace 'incident_subcategory_select', :partial => 'incident_subcategory_select_update'
         page.replace 'incident_subtype_select', :partial => 'incident_subtype_select_update'
     end      

  end

在 Outbreak 视图中（尽管由于该部分与 Incident 相关，因此它可能应该进入该视图）

    <% ActionView::Helpers::FormBuilder.new(:outbreak, @outbreak, @template, {}, proc{}).fields_for :incidents,{:child_index => @next_child_index} do |this_form| %>
<div id="incident_category_select">
<%= render :partial => 'category_select', :locals => {:incident_form => this_form } %>
</div>
<% end %>

ActionView::Helpers::FormBuilder 用于生成表单所需的 fields_for - 网站文章详细介绍了这一点细节。

结果索引由 @next_child_index 变量设置，该变量可以通过原始 AJAX 调用传递到控制器（例如 @next_child_index = 1，则结果表单元素名称将为 outbreak [incidents_attributes] [1] [category_id ] ） - 我在本示例中没有使用此选项，因为尽管将来我希望表单在初始运行中支持每个爆发的多个位置，但它只接受单个位置 - 每次爆发的事件。

_category_select.erb 部分（在 Outbreak 视图 atm 中）

<% with_str = "'category_id=' + value " %>
<% if @outbreak.id %>
<% with_str << "+ '&id=' + #{@outbreak.id}" %>
<% end %>
<%= incident_form.collection_select( :category_id, @categories, :id, :name, {:prompt   => "Select a category"}, {:onchange => "#{remote_function(:url  => { :action => "update_subcategory"}, :with => with_str)}"}) %>

with_str 只是选择性地传递 Outbreak id（如果存在）到控制器以查找 Outbreak 记录以生成表单，如果不构建新的 Outbreak 以及关联的嵌套属性（例如事件和事件）地点。

必须有更简洁的方法来做到这一点 - 特别是 FormHelper 并通过可选的 with 字符串传递 Outbreak id。