Ruby on rails 如何在：if验证中使用枚举值

假设我们有一个枚举

enum status: { pending: 0, finished: 1, extended: 2 }

我们希望根据枚举状态的值创建一个验证

validates_presence_of :explanation, if: ...enum status is equal to "extended"

---

我一直是蛮力，尝试了许多组合，但似乎找不到任何有效的

您可以使用

pending？

class Job < ActiveRecord::Base
  enum status: [ :active, :archived ]
  validates_presence_of :explanation, if: Proc.new { |a| a.extended? }
end

类作业

完整示例：

class Conversation < ActiveRecord::Base
  enum status: [ :active, :archived ]
end

# conversation.update! status: 0
conversation.active!
conversation.active? # => true
conversation.status  # => "active"

# conversation.update! status: 1
conversation.archived!
conversation.archived? # => true
conversation.status    # => "archived"

# conversation.status = 1
conversation.status = "archived"

conversation.status = nil
conversation.status.nil? # => true
conversation.status      # => nil

类对话真的
conversation.status#=>“活动”
#对话。更新！现状：1
对话，存档！
会话是否已存档？#=>真的
conversation.status#=>“已存档”
#会话状态=1
conversation.status=“已存档”
conversation.status=nil
conversation.status.nil？#=>真的
conversation.status#=>无

参考资料：
短版：

validates_presence_of :explanation, if: 'extended?'

---

美好的这也适用于符号：

if:：extended？

。