表单验证 - 如果出现错误，则需要进行此验证

Question

在我的模型表单验证中，我试图说如果名为:virtual的列的参数为false，则:location字段应验证:presence => true。

我目前的代码是：

validates :location, if :virtual => false, :presence => true

但那给了我一个语法错误。格式化的正确方法是什么？

Answer 1

类似的东西：

attr_accessor :virtual  # sets up a "virtual attribute" called "virtual" to which you can read/write a value
                        # this step isn't necessary if you already have an attribute on the model called "virtual"

validates :location, :presence => true, :unless => :virtual?

使用virtual?应检查属性virtual是真还是假。使用unless表示仅在virtual为false时执行此验证（或者是false的值）。

有关虚拟属性和验证的更多详细信息：Rails: Using form fields that are unassociated with a model in validations

Answer 2

validates :location, presence: true, if: Proc.new { |p| p.virtual == false }