Is it possible to put just a rails form element in a partial?

Question

My app has a select box for users to choose a "venue". This select box is, as you would expect, in a form. I also have an action somewhere on the page that creates a new venue via AJAX. After the new venue is created, I would like to updated the venue select box to reflect this.

My solution was to put the select box in a partial and render the partial from the create action in the controller.

 <div id="venue_select" style="clear: both;">
    <%= render :partial => 'venue/venue_select_box' %>
 </div>

The partial looks like this:

<%= f.collection_select :venue_id, @user_venues, :id, :name, :prompt => 'Select a venue' %>

where f is the form reference:

<% form_for :shows do |f| %>

The problem is that f is undefined in the partial, so I get an error. One solution would be to include the entire form, but I feel like that should not be necessary because I am not updating the entire form. Any ideas on how to go about this?

Answer 1

You can pass a variable to the partial like this:

  <%= render :partial => 'venue/venue_select_box', :locals => { :f => f } %>

For stuff like this it is always good to look at the documentation.

EDIT: To use the partial with AJAX request you'll need to "recreate" the form in your .rjs template. So in your controller you'll need to find the object again.

 def venue_select
    @venue = Venue.find(params[:id])
    respond_to do |format|
      format.html
      format.js
    end
 end

Then in your venue/venue_select.rjs file:

 form_for @venue do |f|
   page[:element].replace_html :partial => 'venue/venue_select_box', :locals => { :f => f }
 end

Where :element is the id of the select menu you want to replace. Basically you just recreate the form_for and then use that to update the select field.

Answer 2

It might be easier to add the venue to the selectbox with Javascript, as an onComplete hook on your AJAX add.