New Post: Best practices to invoke validate

I'm confused about what is the best way to call the validator. From within my method of business or outside.

example:

invoke at controller:

var uow = UnitOfWorkFactory.GetInstance();
var userBLL= new UserBLL(uow);
var validator = new UserValidator(userBLL);
var user = .....;
validator.Validade(user);
if (validator.IsValid) {
    ....
}
else {
    ....
}

or at business layer:

var uow = UnitOfWorkFactory.GetInstance();
var userBLL= new UserBLL(uow);

try {
   var user = .....;
   // Inside of the method "Save" I create and invoke the validator adding the result in a exception.
   userBLL.Save(user);
}
catch {
   /// Error of the validator
}

What is the best way? Or there are other options?

Thanks
[]s