如何直接对list进行验证

本文关键字：验证 list 何直接 | 更新日期: 2023-09-27 18:05:23

我有一个模型类:

public class MyModel() { //properties here... }

我想验证一个MyModel对象的列表。所以我创建了这个验证器:

class MyModelListValidator : AbstractValidator<List<MyModel>>
{
    public MyModelListValidator ()
    {
        RuleFor(x => x)
            .SetCollectionValidator(new MyModelValidator())
            .When(x => x != null);
    }
    private class MyModelValidator : AbstractValidator<MyModel>
    {
        public MyModelValidator()
        {
            //MyModel property validation here...
        }
    }
}

但是上面的方法不起作用。另一种方法是创建这样的类:

public class MyModelList()
{
    public List<MyModel> Items { get; set; }
}

这将工作。

但是有没有办法在不使用这个额外的类的情况下做到这一点呢?

如何直接对list进行验证

如果您使用数据注释来执行验证，您可能需要一个自定义属性:

public class EnsureOneElementAttribute : ValidationAttribute
{
    public override bool IsValid(object value)
    {
        var list = value as IList;
        if (list != null)
        {
            return list.Count > 0;
        }
        return false;
    }
}

然后:

[EnsureOneElement(ErrorMessage = "At least a person is required")]
public List<Person> Persons { get; private set; }
or to make it more generic:
public class EnsureMinimumElementsAttribute : ValidationAttribute
{
    private readonly int _minElements;
    public EnsureMinimumElementsAttribute(int minElements)
    {
        _minElements = minElements;
    }
    public override bool IsValid(object value)
    {
        var list = value as IList;
        if (list != null)
        {
            return list.Count >= _minElements;
        }
        return false;
    }
}

然后:

[EnsureMinimumElements(1, ErrorMessage = "At least a person is required")]
public List<Person> Persons { get; private set; }
Personally I use FluentValidation.NET instead of Data Annotations to perform validation because I prefer the imperative validation logic instead of the declarative. I think it is more powerful. So my validation rule would simply look like this:
RuleFor(x => x.Persons)
    .Must(x => x.Count > 0)
    .WithMessage("At least a person is required");
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