MVC自定义验证：DataAnnotations还是IValidatableObject？

I've a question about the different ways of creating a custom validation on MVC. I've to combine two pieces of code that are doing the same thing in two different Areas (MVC Area) of the website. This piece of code is validating a bank account number. One of the versions is using custom validation attribute and the other one IValidatableObject. Now I've to merge everything in one place and add some extra functionality.I've a question about the different ways of cre