public IEnumerable <ValidationResult> Validate(ValidationContext validationContext) { if (Address1 != null && Address2 != null && Address2.ToLower() == Address1.ToLower()) { yield return(new ValidationResult("Address 2 cannot be the same as Address 1.")); } if (State != null && State.Length != 2) { yield return(new ValidationResult("Enter a 2 digit State code.")); } if (Zipcode != null && Zipcode.Length != 5) { yield return(new ValidationResult("Enter a 5 digit Zipcode.")); } }