From: robertlaferla@...
Date: 2007-07-03T04:36:28+09:00
Subject: associating an array to multiple text fields in a form

I have a model that has the following classes: ShoppingList, Item and Product. 

-- *Product* is just a list of product names:  Apple, Orange, Banana, Pear, 
Grape.  The table has two columns: ID and NAME.

-- A *ShoppingList* has a name (string) and many *Item* objects.

-- Each *Item* has a *quantity* (integer) and to-one relationship to a 
*Product*.

My ShoppingList's edit view has a form that contains a textfield for the name of 
a shopping list and a table of items and their quantities:

Name:  MyShoppingList

Qty.  Item
3      Apples
0      Oranges
1      Pear

The model object for this view is, of course, a ShoppingList.

I am trying to bind each text field to the quantity attribute of each item in the shopping list.  I tried something like this but it doesn't work because Rails wants an instance variable to bind to.  How do I properly bind my array?

<% @shopping_list.items.each do |item| %>
<tr>
<td><%= text_field("shopping_list.items[" + item.id.to_s + "].quantity", 
item.quantity, :size => 3) %></td><td><%= (Product.find 
item.product_name_id).name%></td>
</tr>
<% end %>