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我目前正在使用带有这些模型的 Rails 4.2：

class User < ActiveRecord::Base
  has_many :user_accessories, dependent: :destroy
  accepts_nested_attributes_for :user_accessories,
    reject_if: :all_blank,
    allow_destroy: true
  has_many :accessories, through: :user_accessories
end

class UserAccessory < ActiveRecord::Base
  belongs_to :user,      required: true
  belongs_to :accessory, required: true
end

class Accessory < ActiveRecord::Base
  has_many :user_accessories, dependent: :destroy
  has_many :users, through: :user_accessories
end

这是一个简单的多对多关系，其中一个用户可以“拥有”许多配件，而一个配件可以被多个用户“拥有”。

我通过以下方式设置了我的路线： 

resources :users, only: [ :index, :show, :edit, :update, :accessories ] do
  member do
    get 'accessories'
  end
end

这样，用户可以转到他们的“附件”路径 ( /users/1/accessories) 以查看他们的附件列表，以及将新的附件关联添加到他们的帐户。

这是为附件路径呈现的视图： 

<table>
  <thead>
    <tr>
      <th>Name</th>
    </tr>
  </thead>
  <tbody>
    <%= render @accessories %>
  </tbody>
</table>

<%= form_for( @user ) do |f| %>
  <%= f.collection_select( 
    :accessory_ids, 
    Accessory.all, 
    :id, 
    :name, { include_hidden: false }, { multiple: true } ) 
  %>

  <%= f.button "Add Equipment" %>
<% end %>

这只是呈现当前配件的表格，然后构建一个 collection_select 框，您可以在其中选择要添加的多个配件。我通过删除 Bootstrap 样式简化了这一点。

最后，这里是相关的控制器动作： 

def update
  @user = User.find( params[:id] )
  if( @user.update_attributes( update_params ) )
    redirect_to @user
  else
    render 'edit'
  end
end

def accessories 
  @user = User.find( params[:id] ) 
  @accessories = @user.accessories 
end 

private 
  def update_params 
    params.require( :user ).permit( 
      :first_name, 
      :last_name, 
      :region_id, 
      :country, 
      :profile_image, 
      :remove_profile_image, 
      accessory_ids: [:id], 
    )
  end

现在的问题：

  1. 当我已经在数据库中手动输入了一个值时提交表单实际上只是删除了所有当前存储的值而不添加任何新值： 

    Started PATCH "/users/nuggles" for 127.0.0.1 at 2015-02-18 13:31:50 -0500

Processing by UsersController#update as HTML

Parameters: {
  "utf8"=>"✓",····
  "authenticity_token"=>"my_token",·
  "user"=>{
    "accessory_ids"=>["5"]
  },· 
  "button"=>"",·
  "id"=>"nuggles"
} 

User Load (40.0ms)  SELECT  "users".* FROM "users" WHERE "users"."id" = $1  ORDER BY "users"."id" ASC LIMIT 1  [["id", 4]] 

User Load (36.4ms)  SELECT  "users".* FROM "users" WHERE "users"."slug" = $1  ORDER BY "users"."id" ASC LIMIT 1  [["slug", "nuggles"]]·

(33.5ms)  BEGIN

Accessory Load (34.1ms)  SELECT "accessories".* FROM "accessories" INNER JOIN "user_accessories" ON "accessories"."id" = "user_accessories"."accessory_id" WHERE "user_accessories"."user_id" = $1  [["user_id", 4]]

**SQL (34.1ms)  DELETE FROM "user_accessories" WHERE "user_accessories"."user_id" = $1 AND "user_accessories"."accessory_id" IN (1, 2, 3)  [["user_id", 4]]**

User Exists (37.7ms)  SELECT  1 AS one FROM "users" WHERE (LOWER("users"."username") = LOWER('Nuggles') AND "users"."id" != 4) LIMIT 1

(34.2ms)  COMMIT

Redirected to http://localhost:3000/users/nuggles
Completed 302 Found in 304ms (ActiveRecord: 250.0ms)

  2. 提交未选择任何内容的表单时，出现以下错误： 

    param is missing or the value is empty: user

private
  def update_params
    params.require( :user ).permit(
      :first_name,
      :last_name,
      :region_id,
4

1 回答 1

1

对于任何有兴趣的人，我已经让表格工作了。这可能不是一次创建多个记录的理想方式，但它现在对我有用。

首先，我在控制器中取出了奇怪的accessories定义。Users由于我将直接创建、更新和销毁用户的配件，连接模型应该有自己的控制器：

class UserAccessoriesController < ApplicationController
  def index
    @user = User.friendly.find( params[:id] )
    @user_accessories = @user.user_accessories
  end

  def create
    @user = User.friendly.find( params[:id] )

    create_params[:accessory].each do |accessory|
      @user_accessory = UserAccessory.new( user: @user, accessory_id: accessory )

      @user_accessory.save
    end

    redirect_to user_accessories_path( @user )
  end

  def destroy
    @user_accessory = UserAccessory.friendly.find( params[:id] )

    @user_accessory.destroy
  end

  private
    def create_params
      params.require( :user_accessory ).permit(
        :id,
        accessory: []
      )
    end
end

我只有一个视图UserAccessories，即索引。该页面列出了一个用户的所有附件，如果显示的用户与登录的用户相同，则显示如下表格：

  <%= form_for @user_accessories.new(), { method: :post } do |f| %>
    <div class="form-group">
      <%= f.collection_select(
                               :accessory,
                               # Get only accessories not on the user's account
                               Accessory.where.not( id: @user.accessories ),
                               :id,
                               :name,
                               {
                                 include_hidden: false
                               },
                               {
                                 multiple:    true,
                                 class:       'form-control',
                                 placeholder: 'Select Equipment to Add'
                               }
                             ) %>
    </div>

    <div class="form-group">
      <%= f.submit "Update Equipment" %>
    </div>
  <% end %>

这允许用户选择多个附件（使用 select2），然后在提交时在控制器中一一创建关联。

如果有人有更好的方法来创建用户附件（即不循环通过我的参数并创建多次），那么请发表评论！

于 2015-02-27T15:39:25.550 回答