Rails 4：如何通过AJAX更新基于另一个collection_select的collection_select？

Question

问题： 我需要过滤一组单元的集合，其基础是选择一组组织。

在选择组织，则单位下拉菜单应只刷新，显示单位属于知情组织。

我检查了这些问题：

• Rails forms: updating collection_select options based on other collection_select value using AJAX

• UJS, AJAX, Rails 4, form_for collection_select to pass value into method and return value back to form

• ajax in rails with collection_select

• How to add an onchange event to select tag in rails

• Rails forms: updating collection_select options based on other collection_select value using AJAX

• Rails form_for collection_select ignoring remote ajax call that select_tag accepts

• remote select, controller needs more form data

而且这些单证：

• http://guides.rubyonrails.org/form_helpers.html
• http://api.rubyonrails.org/classes/ActionView/Helpers/FormOptionsHelper.html
• http://api.rubyonrails.org/classes/ActionView/Helpers/FormOptionsHelper.html#method-i-options_from_collection_for_select

这是到目前为止我的代码：

模式

class Organization < ActiveRecord::Base 
    has_many :units 
    has_many :projects, through: :units 
end 
class Unit < ActiveRecord::Base 
    belongs_to :organization 
    has_many :projects 
end 
class Project < ActiveRecord::Base 
    belongs_to :organizaton 
    has_one :organization, through: :unit 
end 

查看 应用程序/视图/项目/ _form.html.erb

<%= form_for(@project) do |f| %> 

    <div class="field"> 
    <%= f.label :name %><br> 
    <%= f.text_field :name %> 
    </div> 
    <div class="field"> 
    <%= f.label :description %><br> 
    <%= f.text_area :description %> 
    </div> 
    <div class="field"> 
    <%= f.label :organization_id %><br> 
    <%= f.collection_select :organization_id, Organization.all, :id, :name %> 
    </div> 
    <div class="field"> 
    <%= f.label :unit_id %><br> 
    <%= f.collection_select :unit_id, Unit.all.where(organization_id: :organization_id), :id, :name %> 
    </div> 
    <div class="actions"> 
    <%= f.submit %> 
    </div> 
<% end %> 

个

控制器 项目控制器

def new 
    @project = Project.new 
end 

def project_params 
    params.require(:project).permit(:name, :description, :organization_id, :unit_id) 
end 

我怎样才能使这项工作？

Answer 1

我做到了，该解决方案是非常简单的，但由于缺乏这方面简单的问题更新材料制成它更大一个苦差事比它应该有：

的config/routes.rb中

get 'filter_units_by_organization' => 'projects#filter_units_by_organization' 

控制器/ projects_controller.rb

def filter_units_by_organization 
    @filtered_units = Unit.where(organization_id: params[:selected_organization]) 
end 

层的意见/项目/ filter_units_by_organization.js.erb

$('select#project_unit_id').html('<%= j options_from_collection_for_select(@filtered_units, :id, :name) %>'); 

资产/ Java脚本/ application.js中

$(function() { 
    $("select#project_organization_id").on("change", function() { 
     $.ajax({ 
      url: "/filter_units_by_organization", 
      type: "GET", 
      data: { selected_organization: $("select#project_organization_id").val() } 
     }); 
    }); 
}); 

的意见/项目/ _form.html.erb

<div class="field"> 
    <%= f.label :name %><br> 
    <%= f.text_field :name %> 
    </div> 
    <div class="field"> 
    <%= f.label :description %><br> 
    <%= f.text_area :description %> 
    </div> 
    <div class="field"> 
    <%= f.label :organization_id %><br> 
    <%= f.collection_select :organization_id, Organization.all, :id, :name, { prompt: 'Please select' } %> 
    </div> 
    <div class="field"> 
    <%= f.label :unit_id %><br> 
    <%= f.collection_select :unit_id, Unit.all.where(organization_id: :organization_id), :id, :name %> 
    </div> 
    <div class="actions"> 
    <%= f.submit %> 
    </div> 

Answer 2

而不是在projects表上放置一个副本organization_id您应该设置关系经历单位模型。

class Organization < ActiveRecord::Base 
    has_many :units 
    has_many :projects, through: :units 
end 

class Unit < ActiveRecord::Base 
    belongs_to :organization 
    has_many :projects 
end 

class Project < ActiveRecord::Base 
    belongs_to :unit 
    has_one :organizaton, through: :unit 
end 

这就避免了尴尬的问题，你必须以确保单位和项目有相同的organizaton_id。

这也意味着您在创建项目时不再需要输入来选择组织 - 只是单位。