Rails is a dynamic collection. The value of the selection is not published in the rest of the form.

Question

I populate the select collection (located in partial) based on the value in another collection set.

The dynamic collection selects the values, as expected, but when I submit the form, the value is missing (note that the rest of the data from all the other inputs of the form pass through).

Since the data from the dynamic collection selection is required, the controller redirects you back to the new view. Now, since the value of the first drop-down list has already been selected (since the last time you tried to fill out the form), the dynamic drop-down menu is already loaded with possible choices, and now the value of the dynamic selection is transmitted when the form is submitted. If you change the value of the first collection, select the second, it will not display its value until the second time (as before).

Does anyone know what I'm doing wrong?

Here is what I consider relevant parts of my code:

Partial containing dynamic collection set:

<%= collection_select(:f, :address_id, @addresses, :id, :concatenateAddress, {:include_blank => "Select an Address"}) %>

New and Create actions in my controller:

def new
  @contact = Contact.new
  @companies = ContactCompany.all
  @addresses = []

  respond_to do |format|
    format.html # new.html.erb
    format.xml  { render :xml => @contact }
  end
end

def create
  @contact = Contact.new(params[:contact])

  respond_to do |format|
    if @contact.save
      flash[:notice] = 'Contact was successfully created.'
      format.html { redirect_to(@contact) }
      format.xml  { render :xml => @contact, :status => :created, :location => @contact }
    else
      format.html { render :action => "new" }
      format.xml  { render :xml => @contact.errors, :status => :unprocessable_entity }
    end
  end
end

Details in my view (showing both collection selection cells and my observed field

<tr>
  <td colspan = "2">
    <%= 
      @company = ContactCompany.find(:all)
      f.collection_select(:company_id, @company, :id, :name,{:selected => @contact.company_id }) 
    %>
    <br/>
    <%= link_to 'Company Index', {:controller=>"contact_companies", :action=>"index"} %> | <%= link_to 'New Company', {:controller=>"contact_companies", :action=>"new"}%>
  </td>
  <td><%= f.text_field :phone_number %></td>
  <td><%= f.text_field :fax_number %></td>
</tr>

<tr>
  <td colspan = "2">Address</td>
  <td>Cell Phone</td>
  <td>Alternate Phone</td>
</tr>

<tr>
  <td colspan = "2">
  <% @addresses = ContactCompanyAddress.find(:all, :conditions=> {:company_id => @contact.company_id}) %>
  <%= observe_field "contact_company_id", :url=>{:controller => 'contact_companies', :action=>'ajax_get_addresses', :id => ContactCompany.first}, :with=> 'company_id' %>
  <div id="addresses"><%= render :partial => 'contact_companies/addresses', :object => @addresses, :f => 'f'%> </div>
  <%= link_to 'Address Index', {:controller=>"contact_company_addresses", :action=>"index"} %> | <%= link_to 'New Address', {:controller=>"contact_company_addresses", :action=>"new"}%>
  </td>
</tr>