我应该在 FluentValidation 中创建一个新的集合类型吗？

我试图找到 FluentValidation 中是否有可用的方法，允许在根级别验证集合的验证器。

例如如下所示，验证器可用于CustomerValidator为一堂课Customer。 使用 FluentValidation；

public class CustomerValidator: AbstractValidator<Customer> {
  public CustomerValidator() {
    RuleFor(customer => customer.Surname).NotEmpty();
    RuleFor(customer => customer.Forename).NotEmpty().WithMessage("Please specify a first name");
    RuleFor(customer => customer.Discount).NotEqual(0).When(customer => customer.HasDiscount);
    RuleFor(customer => customer.Address).Length(20, 250);
    RuleFor(customer => customer.Postcode).Must(BeAValidPostcode).WithMessage("Please specify a valid postcode");
  }

  private bool BeAValidPostcode(string postcode) {
    // custom postcode validating logic goes here
  }
}

Customer customer = new Customer();
CustomerValidator validator = new CustomerValidator();
ValidationResult results = validator.Validate(customer);

bool validationSucceeded = results.IsValid;
IList<ValidationFailure> failures = results.Errors;

问题是，如果我有一个List<Customer>我需要验证至少一个客户应该有Surname我如何验证该列表。fluidvalidation 是否有开箱即用的功能，目前，我可以考虑以下两种方式。您能建议什么是最好的方法吗？

1.循环迭代，然后为每个客户调用 validate 方法。

 List<ValidationResult> listOfValidationErrors = List<ValidationResult>();
 // listCustomer is of type List<Customer>
 foreach (var customer in listCustomer)
 {
     CustomerValidator validator = new CustomerValidator();
     listOfValidationErrors.Add(validator.Validate(customer);
 }

2.为 Customer 集合创建一个新的集合类CustomerCollection然后创建一个验证器类CustomerCollectionValidator

    public class CustomerCollection
    {
        public List<Customer> ListOfCustomers { get; set; }

        public CustomerCollection(List<Customer> listOfCustomers )
        {
            this.ListOfCustomers = listOfCustomers ;
        }
    }

然后是验证器类

public class CustomerCollectionValidator: CompositeValidator<CustomerCollection>
    {
        public CustomerCollectionValidator()
        {

            RuleFor(x => x.ListOfCustomers)
                    .Must(ShouldHaveOneSurName)
                    .WithMessage("Should have one Surname in list");

            RuleForEach(x => x.ListOfCustomers).SetValidator<CustomerValidator>();

        }

        public bool ShouldHaveOneSurName(List<Customer> lstCustomers)
        {
            if (lstCustomers== null)
            {
                return false;
            }
            return lstCustomers.Any(x => !String.IsNullOrWhiteSpace(x.SurName);
        }


    }

除了上述两种方法外，Jeremy Skinner还建议了另一种方法here https://github.com/JeremySkinner/FluentValidation/issues/241，它使用继承自AbstractValidator<List<Customer>>。这不适用于原始代码，但 Jeremy 在 6.3 版本中提交了 Fluent Validation 源代码的更改here https://github.com/JeremySkinner/FluentValidation.

以下代码介绍了对根级别集合进行验证的第三种方法。

public class CustomerCollectionValidator : AbstractValidator<List<Customer>> {
  public CustomerCollectionValidator() {
     RuleFor(list => list).SetCollectionValidator(new CustomerValidator());
  }
}