数组 – Rails – grouped_options_for_select

我在使用groups_options_for_select填充选项组的Rails中的选择框时遇到一些困难.

我目前有3个实例变量,我想将其添加到分组选择框的一个整个分组数组中.

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：如何将这3个实例变量转换为分组选择,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.

grouped_options_for_select方法确实是正确的.

由于您尚未提供代码,因此应该会产生所需的分组选项：

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 ] }]]

哪个可用于创建下拉列表：

select_tag 'Food', grouped_options_for_select(...)

或者使用form_helper：

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