FluentValidation：检查两个字段之一是否为空

Question

我有这个模型

public class Person
{
    public int Id { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }  
}

我想创建一个验证，其中 FirstName 或 LastName 必须由用户填写。 我安装了FluentValidation 并创建了一个customvalidator 类

public class PersonValidator:AbstractValidator<Person>
{
    public PersonValidator()
    {
        RuleFor((person=>person.FirstName)//don't know how to check if one is empty
    }
}

要检查一个字段，我可以这样做RuleFor(person => person.FirstName).NotNull();

但是我如何检查其中一个是否为空。

另外，是否可以通过fluentValidation 创建验证后，在客户端使用它来显示错误？

编辑1

    protected void Application_Start()
    {
        AreaRegistration.RegisterAllAreas();

        FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
        RouteConfig.RegisterRoutes(RouteTable.Routes);
        BundleConfig.RegisterBundles(BundleTable.Bundles);
        FluentValidationModelValidatorProvider.Configure();
    }
//creating validation
namespace WebApplication1.Models.CustomValidator
{
    public class PersonValidator:AbstractValidator<Person>
    {
        public PersonValidator()
        {
            RuleFor(m => m.FirstName).NotEmpty().When(m => string.IsNullOrEmpty(m.LastName)).WithMessage("*Either First Name or Last Name is required");
            RuleFor(m => m.LastName).NotEmpty().When(m => string.IsNullOrEmpty(m.FirstName)).WithMessage("*Either First Name or Last Name is required");
        }
    }

}
//model class
[Validator(typeof(PersonValidator))]
public class Person
{
    public Person()
    {
        InterestList = new List<string>();
    }
    public int Id { get; set; }
    public int ContactId { get; set; }
    [RequiredIfEmpty("LastName")]
    public string FirstName { get; set; }
    [RequiredIfEmpty("FirstName")]
    public string LastName { get; set; }
    public string EmailAddress { get; set; }
    public string Phone { get; set; }
    public string Country { get; set; }
    public List<string> InterestList { get; set; } 
}
//view
@model WebApplication1.Models.Person

<script src="@Url.Content("~/Scripts/jquery-1.8.2.min.js")"></script>
<script src="@Url.Content("~/Scripts/jquery.validate.min.js")"></script>
<script src="@Url.Content("~/Scripts/jquery.validate.unobtrusive.min.js")"></script>
<script src="@Url.Content("~/Scripts/jquery.unobtrusive-ajax.min.js")" type="text/javascript"></script>

@Html.ValidationSummary(true)
@using(Html.BeginForm("AddPerson","Person",FormMethod.Post))
{
    <div class="label">First Name</div>
    <div class="input-block-level">@Html.TextBoxFor(m=>m.FirstName)@Html.ValidationMessageFor(m=>m.FirstName)</div>
    <br/>
    <div class="label">Last Name</div>
    <div class="input-block-level">@Html.TextBoxFor(m=>m.LastName)@Html.ValidationMessageFor(m=>m.LastName)</div>
    <button type="submit" class="btn-primary">Submit</button>
}

Answer 1

一个很好的规则集来检查两个字段之一是否为空，以及提出有意义的错误代码如下：

public CustomerSourceValidator()
    {
        CascadeMode = CascadeMode.StopOnFirstFailure;

        RuleFor(x => x)
            .NotNull().WithErrorCode("source_id_or_email_required")
            .When(source => source.Email == null && source.Id == null);

        RuleFor(x => x.Id)
            .NotNull().WithErrorCode("source_id_required")
            .Matches(CommonValidationRegex.CustomerIdRegexString).WithErrorCode("source_id_invalid")
            .When(source => source.Id != null);

        RuleFor(x => x.Email)
            .NotNull().WithErrorCode("source_email_required")
            .Matches(CommonValidationRegex.EmailRegexString).WithErrorCode("source_email_invalid")
            .When(source => source.Email != null);
    }

Answer 2

你可以使用When/Unless条件：

RuleFor(m => m.FirstName).NotEmpty().When(m => string.IsNullOrEmpty(m.LastName));
RuleFor(m => m.LastName).NotEmpty().When(m => string.IsNullOrEmpty(m.FirstName));

或

RuleFor(m => m.FirstName).NotEmpty().Unless(m => !string.IsNullOrEmpty(m.LastName));
RuleFor(m => m.LastName).NotEmpty().Unless(m => !string.IsNullOrEmpty(m.FirstName));

至于您的第二个问题，FluentValidation 适用于客户端验证，但并非所有规则都受支持。 Here 你可以找到客户端支持的验证器：

1. NotNull/NotEmpty
2. 匹配（正则表达式）
3. InclusiveBetween（范围）
4. 信用卡
5. 电子邮件
6. EqualTo（跨属性相等比较）
7. 长度

对于不在列表中的规则，您必须编写自己的 FluentValidationPropertyValidator 并实施 GetClientValidationRules。您可以通过简单的搜索在StackOverflow 上找到一些这样的示例。

Answer 3

最后，这对我有用。我想验证至少需要一个的三个属性。它只返回一次错误消息。

RuleFor(p => p).Cascade(CascadeMode.StopOnFirstFailure)
            .Must(p => !string.IsNullOrWhiteSpace(p.FirstName))
            .When(p => p.Id == 0 && string.IsNullOrWhiteSpace(p.LastName)).WithMessage("At least one is required (Id, FirstName, LastName).")
            .Must(p => !string.IsNullOrWhiteSpace(p.LastName))
            .When(p => p.Id == 0 && string.IsNullOrWhiteSpace(p.FirstName)).WithMessage("At least one is required (Id, FirstName, LastName).")
            .Must(p => p.Id != 0)
            .When(p => string.IsNullOrWhiteSpace(p.FirstName) && string.IsNullOrWhiteSpace(p.LastName)).WithMessage("At least one is required (Id, FirstName, LastName).");

Answer 4

我这样做是为了检查输入的费用是否与之前的费用相同。 如果费用与之前的费用相同，则会出错。这对我有用。

public class CasualMealChargeValidator : AbstractValidator<CasualMealCharge>
{
    public CasualMealChargeValidator(CasualMealCharge CMC)
    {
        //RuleFor(x => x.BankName).NotEmpty().When(pm => pm.PaymentMode == "Cheque").WithMessage("Enter Bank.");
        RuleFor(x => x).Must(x => x.DN != CMC.DN || x.BF != CMC.BF || x.LN != CMC.LN).WithMessage("Not Saved - Meal charges are same as current charges.").WithName("CMFor");
    }
}

Answer 5

试试这个

RuleFor(person => person).Must(person => !string.IsNullOrEmpty(person.FirstName) || !string.IsNullOrEmpty(person.LastName))

Answer 6

我不知道那个库，但如果你只是想检查这两个属性是否为空，那么你可以使用这个：

<del>RuleFor(person =&gt; person.FirstName ?? person.LastName).NotNull();</del>

EDIT 这不起作用，因为它会抛出一个InvalidOperationException。请改用 Zabavsky 的解决方案。