我试图按照Rails 3 with composed_of model and validation编写的方式添加自定义验证，但我得到了一个奇怪的错误：“NoMethodError：undefined method`marked_for_destruction？'为钱“
我不明白出了什么问题。
你能帮助我吗？
型号：
# == Schema Information
#
# Table name: transactions
#
# id :integer not null, primary key
# text :string(255)
# amount_cents :integer default(0), not null
# ...
class Transaction < ActiveRecord::Base
attr_accessible :text, :amount, ...
validates :text, :length => { :maximum => 255 }
composed_of :amount, :class_name => "Money", :mapping => %w(amount_cents cents),
:converter => Proc.new { |value| Money.to_money(value) }
validates :amount, :presence => true, :numericality => { :greater_than_or_equal_to => 0 }
validates_associated :amount
...
end
class Money
attr_reader :cents
def initialize(cents)
@cents = cents
end
class << self
def to_money(str_money)
cents = (str_money.to_f * 100).to_i
Money.new(cents)
end
def to_money?(str_money)
/\A\d+(\.\d+)?\z/ == str_money.to_s
end
end
def ==(value)
@cents == self.class.to_money(value).cents
end
def to_i
@cents
end
def to_f
@cents.to_f
end
def to_s
return nil if @cents.nil?
unit, subunit = @cents.abs.divmod(100)
unit_str = ""
subunit_str = ""
fraction_str = ""
unit_str, subunit_str = unit.to_s, subunit.to_s
subunit_str.insert(0, '0') while subunit_str.length < 2
absolute_str = "#{unit_str}.#{subunit_str}#{fraction_str}"
absolute_str.tap do |str|
str.insert(0, "-") if @cents < 0
end
end
def inspect
"#<Money cents:#{@cents} to_s:#{self.to_s}>"
end
end
错误：
1.9.3p194 :001 > t = Transaction.new
=> #<Transaction id: nil, text: nil, amount_cents: 0, date: nil, created_at: nil, updated_at: nil, transaction_type_id: nil, account_id: nil, user_id: nil, trans_account_id: nil, trans_amount_cents: 0>
1.9.3p194 :002 > t.amount = 100
=> 100
1.9.3p194 :003 > t.valid?
NoMethodError: undefined method `marked_for_destruction?' for #<Money cents:10000 to_s:100.00>
from /home/alexvs/.rvm/gems/ruby-1.9.3-p194@rails3tutorial2ndEd/gems/activerecord-3.2.8/lib/active_record/validations/associated.rb:5:in `block in validate_each'
from /home/alexvs/.rvm/gems/ruby-1.9.3-p194@rails3tutorial2ndEd/gems/activerecord-3.2.8/lib/active_record/validations/associated.rb:5:in `reject'
from /home/alexvs/.rvm/gems/ruby-1.9.3-p194@rails3tutorial2ndEd/gems/activerecord-3.2.8/lib/active_record/validations/associated.rb:5:in `validate_each'
from /home/alexvs/.rvm/gems/ruby-1.9.3-p194@rails3tutorial2ndEd/gems/activemodel-3.2.8/lib/active_model/validator.rb:153:in `block in validate'
from /home/alexvs/.rvm/gems/ruby-1.9.3-p194@rails3tutorial2ndEd/gems/activemodel-3.2.8/lib/active_model/validator.rb:150:in `each'
from /home/alexvs/.rvm/gems/ruby-1.9.3-p194@rails3tutorial2ndEd/gems/activemodel-3.2.8/lib/active_model/validator.rb:150:in `validate'
from /home/alexvs/.rvm/gems/ruby-1.9.3-p194@rails3tutorial2ndEd/gems/activesupport-3.2.8/lib/active_support/callbacks.rb:310:in `_callback_before_21'
from /home/alexvs/.rvm/gems/ruby-1.9.3-p194@rails3tutorial2ndEd/gems/activesupport-3.2.8/lib/active_support/callbacks.rb:462:in `_run__74709952__validate__911291598__callbacks'
from /home/alexvs/.rvm/gems/ruby-1.9.3-p194@rails3tutorial2ndEd/gems/activesupport-3.2.8/lib/active_support/callbacks.rb:405:in `__run_callback'
from /home/alexvs/.rvm/gems/ruby-1.9.3-p194@rails3tutorial2ndEd/gems/activesupport-3.2.8/lib/active_support/callbacks.rb:385:in `_run_validate_callbacks'
from /home/alexvs/.rvm/gems/ruby-1.9.3-p194@rails3tutorial2ndEd/gems/activesupport-3.2.8/lib/active_support/callbacks.rb:81:in `run_callbacks'
from /home/alexvs/.rvm/gems/ruby-1.9.3-p194@rails3tutorial2ndEd/gems/activemodel-3.2.8/lib/active_model/validations.rb:227:in `run_validations!'
from /home/alexvs/.rvm/gems/ruby-1.9.3-p194@rails3tutorial2ndEd/gems/activemodel-3.2.8/lib/active_model/validations/callbacks.rb:53:in `block in run_validations!'
from /home/alexvs/.rvm/gems/ruby-1.9.3-p194@rails3tutorial2ndEd/gems/activesupport-3.2.8/lib/active_support/callbacks.rb:403:in `_run__74709952__validation__911291598__callbacks'
from /home/alexvs/.rvm/gems/ruby-1.9.3-p194@rails3tutorial2ndEd/gems/activesupport-3.2.8/lib/active_support/callbacks.rb:405:in `__run_callback'
from /home/alexvs/.rvm/gems/ruby-1.9.3-p194@rails3tutorial2ndEd/gems/activesupport-3.2.8/lib/active_support/callbacks.rb:385:in `_run_validation_callbacks'
from /home/alexvs/.rvm/gems/ruby-1.9.3-p194@rails3tutorial2ndEd/gems/activesupport-3.2.8/lib/active_support/callbacks.rb:81:in `run_callbacks'
from /home/alexvs/.rvm/gems/ruby-1.9.3-p194@rails3tutorial2ndEd/gems/activemodel-3.2.8/lib/active_model/validations/callbacks.rb:53:in `run_validations!'
from /home/alexvs/.rvm/gems/ruby-1.9.3-p194@rails3tutorial2ndEd/gems/activemodel-3.2.8/lib/active_model/validations.rb:194:in `valid?'
from /home/alexvs/.rvm/gems/ruby-1.9.3-p194@rails3tutorial2ndEd/gems/activerecord-3.2.8/lib/active_record/validations.rb:69:in `valid?'
from (irb):3
from /home/alexvs/.rvm/gems/ruby-1.9.3-p194@rails3tutorial2ndEd/gems/railties-3.2.8/lib/rails/commands/console.rb:47:in `start'
from /home/alexvs/.rvm/gems/ruby-1.9.3-p194@rails3tutorial2ndEd/gems/railties-3.2.8/lib/rails/commands/console.rb:8:in `start'
from /home/alexvs/.rvm/gems/ruby-1.9.3-p194@rails3tutorial2ndEd/gems/railties-3.2.8/lib/rails/commands.rb:41:in `<top (required)>'
from script/rails:6:in `require'