ruby-on-rails - setting selected to nil with select tag in ruby on rails

Question

Hi I am trying to set ":selected => nil" or to a value from a variable like ":selected => val" in the select() in ruby but it is not working in either ways. Please can anyone tell what is wrong with the given below snippet. Thanks

<%= select( map1[:field_name], "id", map1[:field_codes], :selected => nil )%>

<%= select( map1[:field_name], "id", map1[:field_codes], :selected => val )%>

where map1[:field_name] is a string 
and map1[:field_codes] returns a hash
val is a variable containing one of the values from hash.

Answer 1

你的片段工作得很好。用它测试过

hash = { "n" => "no", "y" => "yes" }
val = "yes"
ActionView::Base::new.select("name", "id", hash, selected: val)

它创造了：

<select id="name_id" name="name[id]">
   <option value="no">n</option>
   <option selected="selected" value="yes">y</option>
</select>

您的值val和map1[:field_codes]值不完全匹配，或者如果您启动 Rails 应用程序并检查表单以查看selected="selected"，这可能是 Rails 之外的问题（例如您的浏览器）。

Answer 2

尝试在选项周围放置花括号：

 {:selected => val}