如何在options_from_collection_for_select中预先选择？

Question

我有以下表格：

<%= form_tag users_path, method: :get, id: 'uco' do %>
  <%= select_tag "country", options_from_collection_for_select(ISO3166::Country.countries.sort_by(&:name), 'un_locode', 'name'), :include_blank => true %>
<%= submit_tag "Search" %>
<% end %>

当我提交表格时，我最终会：

  

www.example.com/users?country=US

我希望表单能够预选params[:country]。

但我不知道如何将params[:country]附加到select_tag中。我没试成功：

<%= select_tag "country", options_from_collection_for_select(ISO3166::Country.countries.sort_by(&:name), 'un_locode', 'name', params[:country]), :include_blank => true %>

基于this example from the apidock.

Answer 1

没关系，我用这个答案解决了这个问题：

How to make the select_tag keep value of last search?

:selected => params[:country]