使用 f.select 设置默认值 grouped_options_for_select

Set default value with grouped_options_for_select , using f.select

我有一个由以下呈现的分组下拉菜单,

= f.select :location_id, 
           grouped_options_for_select(grouped_location_options, 
                                      default_location_name), 
           { selected: default_location_name }, 
           class: 'form-control'

我希望默认值未分配,但上面的代码似乎并没有按照我的要求执行喜欢。

有人能给我一些线索来解决这个问题吗??

非常感谢!

您可以使用以下任何格式提供组选项:

    grouped_options = {
          'North America' => [['United States','US'], 'Canada'],
          'Europe' => ['Denmark','Germany','France']
        }

 grouped_options = [
   ['North America', [['United States','US'],'Canada']],
   ['Europe',['Denmark','Germany','France']]
 ]

致 select 我们和 Denmak 使用以下代码:

grouped_options_for_select(grouped_options, ['US', 'Denmark'])

更新:

grouped_options = {
      'Unassigned' => [['Unassigned','1']],
      'Assigned' => [['Trainer 1 Location', 3], ['Trainer 5 Location', 4]] 
    }

至 select 未分配使用:grouped_options_for_select(grouped_options, ['1'])

到select默认赋值pass id of unassigned in grouped_option_from_select