rails select下拉框選擇及設置屬性

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

include_blank設置爲true時，默認的是一個空白顯示
解析HTML
<select name="post[category]">
<option></option>
<option>joke</option>
<option>poem</option>
</select>

include_blank也可以設置一個提示信息只需把值設爲一個你想顯示的即可
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一樣設置提示信息
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屬性是設置標籤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屬性用來做輸出限制
<select name="post[category]">
<option></option>
<option>joke</option>
<option>poem</option>
<option disabled="disabled">restricted</option>
</select>