Question

我很难以深层嵌套的形式访问fields_for对象的关联方法。你能帮我理解我哪里出错吗？

机会模式：

class Opportunity < ActiveRecord::Base
  has_many :seedlings
  accepts_nested_attributes_for :seedlings
end

幼苗模型：

class Seedling < ActiveRecord::Base
  belongs_to :opportunity
  belongs_to :potential_building
  accepts_nested_attributes_for :potential_building
end

PotentialBuilding模型：

class PotentialBuilding < ActiveRecord::Base
  has_many :seedlings
end

我希望我能在hidden_field旁边写下potential_building的名字，但我显然不理解某些东西。我可以将potential_building_id写入页面，就像这样（haml）：

...
= opportunity_form.fields_for :seedlings do |seedling_form|
  = seedling_form.hidden_field :potential_building_id
  = seedling_form.object.potential_building_id # => 73
....

我希望访问该协会的方法会像这样简单，我不明白为什么不这样做。

...
= opportunity_form.fields_for :seedlings do |seedling_form|
  = seedling_form.hidden_field :potential_building_id
  = seedling_form.object.potential_building.name # => undefined method `name' for nil:NilClass
...

你可以帮我理解吗？谢谢。

Answer 1

class Opportunity < ActiveRecord::Base
  has_many :seedlings
  accepts_nested_attributes_for :seedlings
end

http://currentricity.wordpress.com/2011/09/04/the-definitive-guide-to-accepts_nested_attributes_for-a-model-in-rails-3/

如何访问fields_for对象的关联方法？

1 个答案: