From: henkvantijen@...
Date: 2006-12-16T10:40:12+09:00
Subject: binding input elements to params and sessions too

Hi,

I started experimenting with RoR and came across the raw support for
form elements, if the input element is not bound to a Active Record
object. In my case, I was puzzled that I could find no better than this
for a set of filter checkboxes on top of a listing:

	<%= check_box_tag :indexes, 1, checked = @indexes %> Indexes
	<%= check_box_tag :stocks,  1, checked = @stocks  %> Stocks
	<%= check_box_tag :rates,   1, checked = @rates   %> Rates

In the controller I also need some plumbing to connect the params to
the proper vars:

	@stocks   =  params[:stocks]
	@indexes = params[:indexes]
	@rates   =   params[:rates]

Not very DRY.

In contrast, for an input element (without _tag) that I can bind to an
AR object, I only have to say

   	<%= text_field 'prediction', 'predicted_value' %>

and I don't need the plumbing: the binding is 2-way automagically.

Q: Is there some way to say something like
	<%= check_box_tag :params :indexes %> Indexes
if I want to bind the input element to the previous form value, and
    <%= check_box_tag :session :indexes %> Indexes
if I want to bind the input element 2-way to the session var ?

So perhaps what I am saying is, lets use a :binding_type key, that
defaults to active record:

      <%= text_field 'prediction', 'predicted_value' %>  # is default
case of next line

	<%= text_field :binding_type => :active_record, 'prediction',
'predicted_value' %>

	<%= text_field :binding_type => :params,   'predicted_value' %>  #
2-way

	<%= text_field :binding_type => :sessions, 'predicted_value' %> #
2-way

        <%= check_box :binding_type => :sessions, :indexes %>  # 2-way

and so on.
		
Hey, I am new to RoR, so I may have these wild ideas, okay?