Hi all,
I'm relatively new to Rails and I am just figuring out how everything works. I've been mostly impressed with the way things work but I have one issue. Most of the rails code seems so elegant so I have to assume it's my fault for not finding the proper way to do this. I'll explain:
I have a model (session based, so no ActiveRecord):
DrRaven wrote:
I have a model (session based, so no ActiveRecord):
----
class State attr_reader :period, :unit attr_writer :period, :unit
def initialize @period = Period.find(:first) @unit = Unit.find(:first) end
end
----
And a controller:
----
class StateController < ApplicationController
def update @state = session[:state]
@state.period = Period.find(params[:state][:period]) @state.unit = Unit.find(params[:state][:unit])
end
end
----
So far so good. What I want is a simple Ajax form that can update my 'State' model using several select boxes. This seems to work quite alright except for one thing: the form doesn't show my current selection. So when I save my 'Unit' and 'Period' into the 'State' model, they both get saved alright (I've checked this) but the selection box shows default values.
I've solved the problem by using the (ugly) select_tags:
----
<% @state = current_state %>
<% remote_form_for :state, @state, :url => { :controller => 'state', :action => 'update' } do |f| %>
<%= select_tag 'state[period]', options_from_collection_for_select(Period.find(:all), :id, :name, @state.period.id), { 'onchange' => 'this.form.onsubmit();' } %>
<%= select_tag 'state[unit]', options_from_collection_for_select(Unit.find(:all), :id, :name, @state.unit.id), { 'onchange' => 'this.form.onsubmit();' } %>
<% end %>
----
But what I want (and would make the purist in me happy) is:
<% @state = current_state %>
<% remote_form_for :state, @state, :url => { :controller => 'state', :action => 'update' } do |f| %>
<% f.collection_select :period, Period.find(:all), :id, :name, {}, { 'onchange' => 'this.form.onsubmit();' } %>
<% f.collection_select :unit, Unit.find(:all), :id, :name, {}, { 'onchange' => 'this.form.onsubmit();' } %>
<% end %>
----
Can anyone tell me why the selection is not shown. I have done some testing myself and I believe the problem lies with the fact that somehow it fails to correctly compare the @state.period (which it gets from the form's object + collection_select's method_name fields) with the Period.find(:all) version of the object. I also tried to rewrite the entire thing using just the id's (integers) but that doesn't seem to work either.
For
<% f.collection_select :period, Period.find(:all), :id, :name, {} %>
The selected value is @state.period, which is a Period object that can never equal an the value of an option, which are id Integers.
If you really wanted to make this work you could:
1. In your State model add method
def period_id period.id end
and use :period_id as the method in your collection select
2. In your Period model define
def identity self end
def to_s id end
And use the identity method as your collection select value method.