无法在Rails 4中的select form helper上添加类

Question

使用Rails 4.似乎无法添加class到select.我觉得其他属性一样required,autofocus也没有出现:

<%= form.select "availability", options_for_select(1..200), required: 'true', autofocus: 'true', class: 'form-control' %>

输出如下:

<select id="event_availability" name="event[availability]">
  <option value="1">1</option>
  <option value="2">2</option>
  <option value="3">3</option>
  ...
</select>

任何的想法？谢谢.

Answer 1

试试这个

<%= form.select "availability", options_for_select(1..200), {}, {required: 'true', autofocus: 'true', class: 'form-control'} %>

第三个参数的可能选项是:prompt和:include_blank