select_tag

select_tag with options_for_select example

An example of using options_for_select with select_tag

 select_tag 'user_id', options_for_select(@users.collect{ |u| [u.name, u.id] })

This would generate something like:

  <select id="user_id" name="user_id">
    <option value="1">Brad</option>
    <option value="2">Angie</option>
    <option value="3">Jenny</option>
  </select>

options_for_select further example (using a collection and with a default value)

In this example, we are editing a collection of region records, each with its own select list of countries. (Region belongs_to :country.) If the region doesn’t have a country associated, then we want a default message of "unassigned". Of course, if the region does have a country associated then we want that country displayed:

 <% name = "region[" + region.id.to_s + "][country_id]" %>
 <% id = "region_" + region.id.to_s %>

 <%= select_tag(id, options_for_select([["unassigned" , "0" ]] +
                      Country.to_dropdown, region.country_id),
                      {:name => name} ) %>

This give us:

 <select id="region_3" name="region[3][country_id]">
   <option value="0">unassigned</option>
   <option selected="selected" value="12">England</option>
 </select>

NB: we’re using the handy acts_as_dropdown plugin (http://delynnberry.com/projects/acts-as-dropdown/) but we could just as easily prepare the select list with map / collect as above.

select_options_tag - no more worries...

no more explicit options_for_select calls..

  def select_options_tag(name='',select_options={},options={})
    #set selected from value
    selected = ''
    unless options[:value].blank?
      selected = options[:value]
      options.delete(:value)
    end
    select_tag(name,options_for_select(select_options,selected),options)
  end

select_options_tag(‘name’,[[‘oh’,’no’]],:value=>’no’)

Auto-submitting select tag

If you want your form to be submitted when user selects something, use:

  :onchange => "this.form.submit();"

For example:

  select_tag "people", "<option>David</option>", :onchange => "this.form.submit();"

sending an array of multiple options

To make sure that you’ll receive a array you should declare the name of the select with "[ ]" like that:

Example

  <%= select_tag "users[]", options_for_select(@users.collect{|x| [x.name,x.id]}), {:multiple => :multiple, :size => 10} %>

Setting name and id for select_tag

Sometimes you need to use select_tag instead of select (because you’re after more control or need to use optgroups, for example), but still want the id/name conventions that select would give.

In this case, all you need to do is set the first parameter to whatever would be produced by select, and it’ll take care of the id and name attribute automatically, and thus ensure the form data is parsed correctly after submission.

For example, if you want to do something like:

 form_for :comment do |f|
  f.select :article_id ...

which would give a select tag with id of "comment_article_id" and a name attribute of "comment[article_id]", which be parsed into the params hash of:

  'comment' => {'article_id' => ...

you can instead do

 form_for :comment do |f|
  select_tag 'comment[article_id]' ...

which will give the same id and name attributes for the select tag and hence the same params hash in the controller