Rails-仅当另一个字段具有特定值时，才如何验证一个字段? [英] Rails - How to validate a field only if a another field has a certain value?

问题描述

我对Rails还是很陌生，现在遇到了一个无法与我的朋友Google解决的问题:)

I'm pretty new to Rails and I now came across a problem which I wasn't able to solve with my friend Google :)

在我的表单中，我有一个带有三个值的Select:苹果，香蕉和樱桃.如果让我选择的苹果从选择我躲在另一个选择 - 和文本场与一些JavaScript，因为当苹果选择，没有必要填补这些其他两个字段了.

In my form I have a Select with three values: Apple, Banana and Cherry. If I choose Apple from the select I hide another Select- and a Text-field with some Javascript, because when Apple is chosen, there is no need to fill in these other two fields anymore.

所以现在我在提交表单时验证表单时遇到了问题. 我发现了一些类似的问题，例如 仅当另一个字段为空白时才验证该字段."

So now I have a problem with validating my form when it's submitted. I've found some similar problems for example in the case of "Only validate a field if another is blank."

此问题的解决方法如下:

This Problem was solved like this:

validates_presence_of :mobile_number, :unless => :home_phone?

所以我刚刚尝试了想到的第一件事:

So I've just tried the first thing which popped into my mind:

validates_presence_of :state, :granted_at, :if => :type != 1

但是当我运行它时，出现此错误:

But when I run it, I get this error:

undefined method `validate' for true:TrueClass

所以现在我不知道如何从已创建的对象访问值... 在此先感谢您的帮助，我希望我的问题不会像听起来那样明显:-)

So now I didn't find out how I can access values from the object which was created... Thank you in Advance for your help and I hope my question isn't as obvious as it sounds :-)

推荐答案

由于它是可执行代码，因此需要将其包装在lambda或Proc对象中，如下所示:

Because it is executable code you need to wrap it in a lambda or a Proc object like so:

validates_presence_of :state, :granted_at, :if => lambda { |o| o.type != 1 }

# alternatively:
..., :if => lambda { self.type != 1 }
..., :if => Proc.new { |o| o.type != 1 }
..., :if ->(o) { o.type != 1 }

这篇关于Rails-仅当另一个字段具有特定值时，才如何验证一个字段?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！