c# - Fluent Validation 链式规则不适用于多个 When 条件

Question

我有一个非常有趣的行为。我有以下两个测试用例:

[Fact]
public void Ctor_WhenNeverIsTrueAndAfterOcurrenceIsNotNull_HasError()
{
    // arrange
    var reccurenceEnd = new RecurrenceEnd()
    {
         IsNever = true,
         AfterOccurence = 1
     };

     // act
     var validator = GetValidator();

     // assert
     validator.ShouldHaveValidationErrorFor(p => p.AfterOccurence, reccurenceEnd);
}

[Fact]
public void Ctor_WhenNeverIsFalseAndAfterOccurenceIsNullAndByDateIsNull_HasError()
{
    // arrange
    var reccurenceEnd = new RecurrenceEnd()
    {
        IsNever = false,
        AfterOccurence = null,
        ByDate = null
    };

    // act
    var validator = GetValidator();

    // assert
    validator.ShouldHaveValidationErrorFor(p => p.AfterOccurence, reccurenceEnd);
}

在我的验证器上，如果我有以下条件，第一个测试失败，第二个通过。如果我改变规则的顺序，第一个测试通过，第二个失败。

RuleFor(dto => dto.AfterOccurence)
    .Cascade(CascadeMode.StopOnFirstFailure)
    .Null()
        .When(p => p.IsNever == true)
    .NotEmpty()
        .When(p => p.IsNever == false && p.ByDate == null);

如果我将验证器更改为以下内容，则两个测试都会通过。

RuleFor(dto => dto.AfterOccurence)
    .Null()
        .When(p => p.IsNever);
RuleFor(dto => dto.AfterOccurence)
    .NotEmpty()
        .When(p => p.IsNever == false && p.ByDate == null);

我设置错了吗？

Answer 1

好的，从 FluentValidation 的 github-issues 得到了答案:

Hi, this is related to you use of the When condition. By default, a When condition applies to all previous validators in the same RuleFor call, so when you use a single call to RuleFor, you’re essentially doubling up on conditions. You should either use separate calls to RuleFor (as you have in your second example), or use the other overload of When that allows you to specify ApplyConditionTo.CurrentValidator

第二种解决方案是:

RuleFor(dto => dto.AfterOccurence)
    .Cascade(CascadeMode.StopOnFirstFailure)
    .Null()
        .When(p => p.IsNever == true)
    .NotEmpty()
        .When(p => p.IsNever == false && p.ByDate == null, ApplyConditionTo.CurrentValidator);