如何在IronRuby中实现包含clr事件的接口

我正在试验IronRuby和WPF,我想写我自己的 commands . 我下面所说的是我所能理解的。

class MyCommand
  include System::Windows::Input::ICommand
  def can_execute()
    true
  end
  def execute()
    puts "I'm being commanded"
  end
end

但ICommand接口定义了CanExecuteChanged事件。我如何在IronRuby中实现它?

编辑:感谢凯文的回应

下面是基于DLR的27223变更集的工作原理。传递给can_execute和execute的值为零。

class MyCommand
  include System::Windows::Input::ICommand
  def add_CanExecuteChagned(h)
    @change_handlers << h
  end
  def remove_CanExecuteChanged(h)
    @change_handlers.remove(h)
  end
  def can_execute(arg)
     @can_execute
  end
  def execute(arg)
    puts "I'm being commanded!"
    @can_execute = false
    @change_handlers.each { |h| h.Invoke(self, System::EventArgs.new) }
  end
  def initialize
    @change_handlers = []
    @can_execute = true
  end
end