passing dynamic params field

Im working with Rails 3.0.3

I want to create bills in my App. Each Bill has many entries (Material, how much of that and the Price)

The Problem i have, is that i want to write the b开发者_如何学Goill and the entries and then save both at the same time. So when you click on save Bill, the Bill + each Entry should be created (saved in the db).

I can write the bill + each entry (with javascript), but i dont know how i could save both of them. Right now i can only save the bill it selft. Is it possible to pass a dynamic field via params so i can handle that in the bills controller to save? How would you implement this?

What you are looking for is called nested form, you have a main form for your bill and multiple forms that are dynamically generated as children of this general form using fields_for like this:

<% form_for @bill do |f| %>
  <%= f.error_messages %>
  <p>
    <%= f.label :name %><br />
    <%= f.text_field :name %>
  </p>
  <% f.fields_for :entry do |builder| %>
    <%= render "entry", :f => builder %>
  <% end %>
  <p><%= f.submit "Submit" %></p>
<% end %>

Of course you will need some js for the dynamic creation of the different entries, here you have a couple of railscasts that will be helpfull.

Nested model form Part 1 Nested model form Part 2