在options_for_select标记的选择列表中包含第一项的空白

Question

我试过了:include_blank => true,但没办法.

<select>
    <%= options_for_select Model.all.collect{|mt| [mt.name, mt.id]} %>
</select>

如果我需要将它添加到集合中,你会怎么做？

Answer 1

我想你想要这种格式:

select("model_name", "model_id", Model.all.collect {|mt| [ mt.name, mt.id ] }, {:include_blank => 'name of your blank prompt'})

BTW:假设Modle被认为是Model.要使用collection_select:

collection_select(:model, :model_id, Model.all, :id, :name, :prompt => true)

Answer 2

我相信这些:include_blank选项仅适用select于与模型相关的字段.

假设您要使用普通<select>标签而不是<%= select(...) %>绑定到模型,您可以在结果的前面插入一个空白条目:

<%= options_for_select Modle.all.collect{|mt| [mt.name, mt.id]}.insert(0, "") %>

Answer 3

既然你已经标记为选择标签,你可以使用的选项include_blank有select_tag.

从文档:

select_tag "people", options_from_collection_for_select(@people, "id", "name"), :include_blank => true

# => <select id="people" name="people"><option value=""></option><option value="1">David</option></select>

或者您可以使用options_for_select:

<%= select_tag column.name, options_for_select(Model.all.collect{|mt| [mt.name, mt.id]}), :include_blank => true %>

Answer 4

<%= options_for_select Model.all.collect{|x| [x.name,x.id]}.unshift(["",nil]) %>