我有这些模型:

class Organisation < ActiveRecord::Base

  has_many    :people
  has_one     :address, :as         => :addressable,
                        :dependent  => :destroy
  accepts_nested_attributes_for :address, :allow_destroy => true

end

class Person < ActiveRecord::Base

  attr_accessible :first_name, :last_name, :email, :organisation_id, :address_attributes

  belongs_to  :user
  belongs_to  :organisation
  has_one     :address, :as         => :addressable,
                        :dependent  => :destroy
  accepts_nested_attributes_for :address, :allow_destroy => true

  # These two methods seem to have no effect at all!
  validates_presence_of :organisation,  :unless => "address.present?"
  validates_associated  :address,       :unless => "organisation.present?"

end

class Address < ActiveRecord::Base

  belongs_to :addressable, :polymorphic => true

  validates_presence_of :line1, :line2, :city, :zip

end

<%= render 'shared/error_messages', :object => f.object %>
<fieldset>
<div class="left">
    <%= f.label :first_name %><br/>
    <%= f.text_field :first_name %>
</div>
<div>
    <%= f.label :last_name %><br/>
    <%= f.text_field :last_name %>
</div>
<div>
    <%= f.label :email %><br/>
    <%= f.text_field :email %>
</div>
<div>
    <%= f.label :organisation_id %><br/>
    <%= f.select(:organisation_id, current_user.organisation_names, {:include_blank => "--- None ---"}, :id => 'organisation_select') %>
</div>
</fieldset>

<%= f.fields_for :address do |address| %>
  <%= render 'shared/address', :f => address %>
<% end %>

<fieldset id="address_fields">
<div>
    <%= f.label :line1 %>
    <%= f.text_field :line1 %>
</div>
<div>
    <%= f.label :line2 %>
    <%= f.text_field :line2 %>
</div>
<div>
    <%= f.label :zip %>
    <%= f.text_field :zip %>
</div>  
<div>
    <%= f.label :city %>
    <%= f.text_field :city %>
</div>  
</fieldset>

def new
  puts params.inspect
  @person = Person.new(:organisation_id => params[:organisation_id])
  @person.build_address
  @title = "New person"
end

{"action"=>"new", "controller"=>"people"}

def edit
  puts params.inspect
  @title = @person.name
end

{"action"=>"edit", "id"=>"69", "controller"=>"people"}

def create
  puts params.inspect
  if params[:organisation_id]
    @person = current_user.organisations.build_person(params[:person])
  else
    @person = current_user.people.build(params[:person])
  end
  if @person.save
    flash[:success] = "Person created."
    redirect_to people_path
  else
    render :action => "new"
  end
end

{"commit"=>"Create", "action"=>"create", "person"=>{"last_name"=>"Doe", "organisation_id"=>"9", "email"=>"john.doe@email.com", "first_name"=>"John", "address_attributes"=>{"city"=>"Chicago", "zip"=>"12345", "line2"=>"Apt 1", "line1"=>"1 Main Street"}}, "authenticity_token"=>"Jp3XVLbA3X1SOigPezYFfEol0FGjcMHRTy6jQeM1OuI=", "controller"=>"people", "utf8"=>"✓"}

validates :address, :presence => true, :if => "organisation_id.blank?"

最佳答案

首先，我想确定你的意思是blank?而不是 present? .通常，我看到这个:

validate :address, :presence_of => true, :if => 'organisation.present?'

validates_associated :address

accepts_nested_attributes_for :address, :allow_destroy => true, :reject_if => :no_organisation

def no_organisation(attributes)
  attributes[:organisation_id].blank?
end

:if => "organisation.blank?"

accepts_nested_attributes_for :address, :allow_destroy => true, :reject_if => :attributes_blank?

def attributes_blank?(attrs)  
  attrs.except('id').values.all?(&:blank?)  
end  

关于ruby-on-rails - Ruby on Rails : How to validate nested attributes on certain condition?，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/12770018/