public override IEnumerable <ErrorInfo> PerformComplexValidation() { List <ErrorInfo> errorList = new List <ErrorInfo>(); if (DateOfBirth.Year == null || DateOfBirth.Month == null || DateOfBirth.Day == null || !DateOfBirth.ToDateTime().Between(DateUtil.CurrentDateTime.AddYears(-99), DateUtil.CurrentDateTime.AddYears(-18))) { errorList.Add(new ErrorInfo("DateOfBirth", "Please enter a valid date of birth, You must be over the age of 18")); } return(errorList); }