I am working on a form (using SimpleForm) that allows you to edit
embedded
associations. The problem that I’m running into is that the nested
models
are subclasses so they are different types with potentially different
fields. I’m creating hidden forms for each type of model, and using
JavaScript to display the form for the selected type. I’m using Mongoid
and
SimpleForm, but I expect the implementation would be the same using
ActiveRecord and the standard Rails form helpers.
Here’s a simplified example of what I have so far:
class Garage
include Mongoid::Document
embeds_one :vehicle
accepts_nested_attributes_for :vehicleend
class Vehicle
include Mongoid::Document
embedded_in :garage
attr_accessible :_typeend
class Car < Vehicle
field :car_field
attr_accessible :car_fieldend
class Truck < Vehicle
field :truck_field
attr_accessible :truck_fieldend
In the console:
garage = Garage.new> garage.vehicle = Car.new(car_field: ‘something’)>
garage.save!
In the form:
= simple_form_for @garage do |f|
= f.input :vehicle do |vehicle_form|
= vehicle_form.input :_type, collection: [‘Car’, ‘Truck’]
%span.hide{data:{fields-for:‘Car’}}
= vehicle_form.input :car_field
%span.hide{data:{fields-for:‘Truck’}}
= vehicle_form.input :truck_field
:coffeescript
$(’#garage_vehicle_attributes__type’).change ->
type = $(@).find(‘option:selected’).val()
$(’[data-fields-for="’ + type + ‘"]’).show()
The problem that will occur in this example is that it won’t be able to
render the truck_field becauseCar does not have a truck_field method.
I’m
not sure how to solve this problem besides throwing out any form helpers
and managing the html and field values manually. Even after much
Googling,
I haven’t been able to find any examples of this type of form.
How can this problem be solved in a standard, “Rails way” using existing
form helpers?
Any tips or advice you can give would be greatly appreciated. Thanks!