arrays - Rails - grouped_options_for_select

Question

我在使用 grouped_options_for_select 使用选项组填充 Rails 中的选择框时遇到了一些困难.

我目前有 3 个实例变量，我想将它们添加到分组选择框的一个完整分组数组中。

例如，我有:

@fruits (which contains the object(s))
   --- !ruby/object:Fruits
      attributes:
      id: 2
      name: Banana

@veggies (which contains the object(s))
   --- !ruby/object:Veggies
      attributes:
      id: 23
      name: Celery
   --- !ruby/object:Veggies
      attributes:
      id: 24
      name: Carrots

@junk_food (which contains the object(s))
   --- !ruby/object:Junk
      attributes:
      id: 11
      name: Snickers
   --- !ruby/object:Junk
      attributes:
      id: 12
      name: Ice Cream

我的问题是:如何获取这 3 个实例变量并将它们转换为分组选择，例如:

  <select>
    <optgroup label="Fruits">
      <option value="2">Banana</option>
    </optgroup>
    <optgroup label="Veggies">
      <option value="23">Celery</option>
      <option value="24">Carrots</option>
    </optgroup>
    <optgroup label="Junk">
      <option value="11">Snickers</option>
      <option value="12">Ice Cream</option>
    </optgroup>
  </select>

food_controller.erb

@fruits = Fruit.all
@veggies = Veggies.all
@junk_food = JunkFood.all

# Then, I'd create the array here using the items above?

我知道我应该使用 grouped_items_for_select ，但我继续遇到一堆错误，我不确定这样做的正确方法。

Answer 1

grouped_options_for_select方法确实是正确的。
由于您尚未提供代码，这应该会产生您想要的分组选项:

grouped_options_for_select [['Fruits',  @fruits.collect {|v| [ v.name, v.id ] }],
                            ['Veggies', @veggies.collect {|v| [ v.name, v.id ] }],
                            ['Junk',    @junk_food.collect {|v| [ v.name, v.id ] }]]

可用于创建下拉列表:

select_tag 'Food', grouped_options_for_select(...)

或使用 form_helper:

f.select :food_attribute, grouped_options_for_select(...)