rails select下拉框选择及设置属性

select(“post”, “category”, Post::CATEGORIES, {include_blank: true})

include_blank设置为true时，默认的是一个空白显示
解析HTML
   <select name="post[category]">
     <option></option>
     <option>joke</option>
     <option>poem</option>
   </select>

include_blank也可以设置一个提示信息只需把值设为一个你想显示的即可
select("post", "person_id", Person.all.collect {|p| [ p.name, p.id ] }, {include_blank: 'None'})
解析HTML
<select name="post[person_id]">
  <option value="">None</option>
  <option value="1">David</option>
  <option value="2" selected="selected">Sam</option>
  <option value="3">Tobias</option>
</select>

prompt跟include_blank一样设置提示信息
select(“post”, “person_id”, Person.all.collect {|p| [ p.name, p.id ] }, {prompt: 'Select Person'})
解析HTML
<select name="post[person_id]">
  <option value="">Select Person</option>
  <option value="1">David</option>
  <option value="2">Sam</option>
  <option value="3">Tobias</option>
</select>

select("album[]", "genre", %w[rap rock country], {}, { index: nil })
：index属性是设置标签id
<select name="album[][genre]" id="album__genre">
  <option value="rap">rap</option>
  <option value="rock">rock</option>
  <option value="country">country</option>
</select>

select(“post”, “category”, Post::CATEGORIES, {disabled: 'restricted'})
:disabled属性用来做输出限制
<select name="post[category]">
  <option></option>
  <option>joke</option>
  <option>poem</option>
  <option disabled="disabled">restricted</option>
</select>