Is there a way to call a method on the data loaded into a form input in Rails? (Specifically a text_field)

I'm using Rails 3.0.5, and for the reasons specified in this question, I need to call a utc_to_local method on the text_field input for a datetime.

I've tried calling the method in various ways directly in the view (as a starting point), but I can't seem to find the magic mix (haven't called a method on a form field before).

/events/edit.html.erb (full file):

<h1>Edit This Event</h1>
<%= form_for(@event) do |f| %>
    <%= render 'fields', :f => f %>
    <div class="actions">
        <%= f.submit "Update Event" %>
    </div>
<% end %>

events/_fields.html.erb (relevant lines only:)

<div class="field">
    <%= f.label      :time_start, "Start Time" %><b开发者_C百科r />
    <%= f.text_field  :time_start, :class => "datetimefield" %>
</div>

To answer straight:

<%= f.text_field  :time_start, :value => f.object.time_start.try(:method_name) :class => "datetimefield" %>

But... why don't you use in_time_zone?

Time.now.in_time_zone("Eastern Time (US & Canada)")

Which would lead to the creation of an Application Helper:

def time_zoned(string)
  return nil if string.nil?
  begin 
    time = Time.parse(string)
  rescue
    return nil
  end
  time.in_time_zone("Eastern Time (US & Canada)")
end

And in your view:

<%= f.text_field  :time_start, :value => time_zoned(f.object.time_start) %>