FluentValidation - 没有代码重复的预验证/条件验证

FluentValidation - pre-validation / conditional validation with no code duplication

我正在尝试创建验证,它可以有两个组并在第一次失败时阻止第二次验证(它包含许多规则)。

现在我确实在内部和 'main validator' 中创建了一个私有的 'BasicValidation' class 这样做:

RuleFor(m => m).SetValidator(new BasicValidation()).DependentRules(() => {
//Complex validation
RuleFor(m => m.IdOfSthInDb)
    .MustAsync(ItemMustExists)
    .WithMessage("Item does not exist.");
});            

它可以解决问题,但我想避免为每个模型创建 'BasicValidation'。

我认为 hext 代码可以解决您的问题:

var basicValidator = new BasicValidation();
RuleFor(m => m).SetValidator(basicValidator));

When(m => basicValidator.Validate(m).IsValid, () => 
{
    RuleFor(m => m.IdOfSthInDb)
        .MustAsync(ItemMustExists)
        .WithMessage("Item does not exist.");
});

在我之前的回答中我误解了这个问题。主要目标是避免不同验证器中的代码重复。经过一番调查,我找到了符合您要求的解决方案。假设你有模型:

public abstract class BaseModel
{
    public string BaseProperty1 { get; set; }
    public string BaseProperty2 { get; set; }
}

public class ChildModel : BaseModel
{
    public int IdOfSthInDb { get; set; }
}

您必须为基础模型创建验证器(它将被进一步使用):

class InternalBaseModelValidator : AbstractValidator<BaseModel>
{
    public InternalBaseModelValidator()
    {
        RuleFor(x => x.BaseProperty1).NotEmpty().WithMessage("Property 1 is empty");
        RuleFor(x => x.BaseProperty2).NotEmpty().WithMessage("Property 2 is empty");
    }
}

然后您可以使用 FluentValidation 的新功能,称为 PreValidate:

public class BaseModelValidator<T>: AbstractValidator<T> where T : BaseModel
{
    // necessary for reusing base rules
    private readonly InternalBaseModelValidator preValidator; 

    protected BaseModelValidator()
    {
        preValidator = new InternalBaseModelValidator();
    }

    protected override bool PreValidate(ValidationContext<T> context, ValidationResult result)
    {
        var preValidationResult = preValidator.Validate(context.InstanceToValidate);
        if (preValidationResult.IsValid)
        {
            return true;
        }

        foreach(var error in preValidationResult.Errors)
        {
            result.Errors.Add(new ValidationFailure(error.PropertyName, error.ErrorMessage, error.AttemptedValue));
        }

        return false;
    }
}

为所有基本模型创建验证器后,您可以从它继承以进行 ChildModel 验证:

public class ChildModelValidator : BaseModelValidator<ChildModel>
{
    public ChildModelValidator() 
        : base()
    {
        RuleFor(x => x.IdOfSthInDb)
            .MustAsync(ItemMustExists)
            .WithMessage("Item does not exist.");
    }

    private Task<bool> ItemMustExists(int arg1, CancellationToken arg2)
    {
        return Task.FromResult(false); // some logic here
    }
}

就是这样!