Showing which option is selected in rails dropdown

Question

I have this code:

%tr
  %th Parent      
  %td
    %select{ :name => "firstlevel_id", :value => "#{@s.firstlevel_id}" }
      - Firstlevel.find(:all).each do |f|
        %option{ :value => "#{f.id}" } #{f.title}

but even if the firstlevel_id is already one of the id's in the options list, it doesn't show it as selected.

Answer 1

1. You can use select_tag helper to create select tag and control selected value.

2. You can also set selected attribute on proper option tag:

    %select{:name => "firstlevel_id"} - FirstLevel.find(:all).each do |f| %option{:value => f.id, :selected => f.id == @s.firstlevel_id} #{f.title} 

I would prefer the first solution.

Answer 2

您应该使用select_tag生成html，并使用options_for_select生成html：

select_tag :firstlevel_id, options_for_select( Firstlevel.all.map{|l| [l.title, l.id] }, @s.try(:firstlevel_id) )