嵌套对象窗体未按预期工作

我想找一个 nested model forms

我在Rails 3 beta 3上。

我的模型和预期的一样:

class Recipe < ActiveRecord::Base
  has_many :ingredients, :dependent => :destroy
  accepts_nested_attributes_for :ingredients
  attr_accessible :name
end
class Ingredient < ActiveRecord::Base
  attr_accessible :name, :sort_order, :amount
  belongs_to :recipe  
end

我可以使用Recipe.contracents\u attributes=如预期:

recipe = Recipe.new
recipe.ingredients_attributes = [ {:name=>"flour", :amount=>"1 cup"}, {:name=>"sugar", :amount=>"2 cups"}]
recipe.ingredients.size    # -> 2; ingredients contains expected instances

as shown in the documentation :

params = { :name => "test", :ingredients_attributes => [ {:name=>"flour", :amount=>"1 cup"}, {:name=>"sugar", :amount=>"2 cups"}] }
recipe = Recipe.new(params)
recipe.name    # -> "test"
recipe.ingredients    # -> []; no ingredient instances in the collection

我是不是做错什么了?还是Rails 3测试版有问题?

这是一个由 attr_accessible :name 在菜谱里。这不具体。