使用Rails 4与HABTM关系的多选问题4 [英] Multiple select issue with a HABTM relationship using Rails 4

问题描述

尽管代码似乎是正确的，但当我尝试发送表单时，多重选择的值并未发送。

如果我只是删除多重选项，一切都按预期工作，只考虑一个值，但每个交易存储一个以上的代码非常重要。

p>

Transaction.rb

  class Transaction< ; ActiveRecord :: Base 
 has_and_belongs_to_many：tags 
  

Tag.rb

  class tag< ActiveRecord :: Base 
 has_and_belongs_to_many：交易
  

查看

 <％= form.collection_select：tag_ids，@tags，：id，：name，{}，
 {多个=> true}％> 
  

结果：

 < select id =transaction_tag_idsmultiple =multiplename =transaction [tag_ids] []> 
< option value =1> ..< / option> 
< / select> 
  

解决方案

确保您正确允许接收的参数用于质量分配。

你说这个参数有效，所以我假设你在你的控制器中有什么地方：

  params.require（：transaction）.permit（：name，：tag_ids）
  

所以你需要允许接收一个数组：

  params.require（：transaction）.permit（： name，：tag_ids => []）
  

Although the code seems to be right, when I try to send the form, the values of the multiple select aren't being sent.

If I just remove the multiple option, everything works as expected considering just one value, but it's important to store more than one tag per transaction.

Model

Transaction.rb

class Transaction < ActiveRecord::Base
    has_and_belongs_to_many :tags

Tag.rb

class tag < ActiveRecord::Base
    has_and_belongs_to_many :transactions

View

<%= form.collection_select :tag_ids, @tags, :id, :name, {}, 
    {:multiple => true} %>

Result:

<select id="transaction_tag_ids" multiple="multiple" name="transaction[tag_ids][]">  
    <option value="1">..</option>
</select>

解决方案

Be sure what you properly allow received params for mass assignment.

You said that the one param works, so I assume what you have somewhere in your controller something like:

params.require(:transaction).permit(:name, :tag_ids)

So you need allow to receive an array:

params.require(:transaction).permit(:name, :tag_ids => [])

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