public void AddUser() { if (!UserValidator.ValidateUserProperties(FirstName, LastName, StreetName, HouseNumber, ApartmentNumber, PostalCode, Town, PhoneNumber)) { MessageBoxFactory.DisplayFormNotFilledMessage(); } else if (!UserValidator.ValidateBirthday(Birthday)) { MessageBoxFactory.DisplayWrongDateFormatMessage(); } else { IUser newUser = UserFactory.CreateUser(FirstName, LastName, StreetName, HouseNumber, ApartmentNumber, PostalCode, Town, PhoneNumber, DateTime.Parse(Birthday)); UsersContainer.AddUser(newUser); CloseWindow(); } }