使用fluentvalidation和asp.net mvc LessThanOrEqualTo进行的不引人注目的客户端

RuleFor(x => x.StartDate)
    .LessThanOrEqualTo(x => x.EndDate.Value)
    .WithLocalizedMessage(() => CommonRes.Less_Than_Or_Equal_To, filters => CommonRes.Start_Date, filters => CommonRes.End_Date);
RuleFor(x => x.StartDate)
    .GreaterThanOrEqualTo(x => x.AbsoluteStartDate)
    .LessThanOrEqualTo(x => x.AbsoluteEndDate)
    .WithLocalizedMessage(() => CommonRes.Between, filters => CommonRes.Start_Date, filters => filters.AbsoluteStartDate, filters => filters.AbsoluteEndDate);

如文档中所述，客户端验证不支持LessThanOrEqualTo或GreaterThanOrEqualTo规则。

这意味着，如果你想对它们进行客户端验证，你需要编写一个自定义的FluentValidationPropertyValidator并实现GetClientValidationRules方法，这将允许你注册一个自定义适配器并用javascript实现它的客户端验证逻辑。

如果你对如何实现这一点感兴趣，请联系我，我将提供一个例子。

---

更新

根据请求，我将尝试展示一个如何实现LessThanOrEqualTo规则的自定义客户端验证的示例。这只是一个日期不可为null的特殊情况。为所有可能的情况编写这样的自定义客户端验证器当然是可能的，但这需要付出更多的努力。

因此，我们从一个视图模型和一个相应的验证器开始：

[Validator(typeof(MyViewModelValidator))]
public class MyViewModel
{
    [Display(Name = "Start date")]
    [DisplayFormat(DataFormatString = "{0:yyyy-MM-dd}", ApplyFormatInEditMode = true)]
    public DateTime StartDate { get; set; }
    public DateTime DateToCompareAgainst { get; set; }
}
public class MyViewModelValidator : AbstractValidator<MyViewModel>
{
    public MyViewModelValidator()
    {
        RuleFor(x => x.StartDate)
            .LessThanOrEqualTo(x => x.DateToCompareAgainst)
            .WithMessage("Invalid start date");
    }
}

然后是一个控制器：

public class HomeController : Controller
{
    public ActionResult Index()
    {
        var model = new MyViewModel
        {
            StartDate = DateTime.Now.AddDays(2),
            DateToCompareAgainst = DateTime.Now
        };
        return View(model);
    }
    [HttpPost]
    public ActionResult Index(MyViewModel model)
    {
        return View(model);
    }
}

和一个视图：

@model MyViewModel
@using (Html.BeginForm())
{
    @Html.Hidden("DateToCompareAgainst", Model.DateToCompareAgainst.ToString("yyyy-MM-dd"))
    @Html.LabelFor(x => x.StartDate)
    @Html.EditorFor(x => x.StartDate)
    @Html.ValidationMessageFor(x => x.StartDate)
    <button type="submit">OK</button>
}

到目前为止，所有这些都是标准的东西。它可以工作，但无需客户端验证。

第一步是写入FluentValidationPropertyValidator:

public class LessThanOrEqualToFluentValidationPropertyValidator : FluentValidationPropertyValidator
{
    public LessThanOrEqualToFluentValidationPropertyValidator(ModelMetadata metadata, ControllerContext controllerContext, PropertyRule rule, IPropertyValidator validator)
        : base(metadata, controllerContext, rule, validator)
    {
    }
    public override IEnumerable<ModelClientValidationRule> GetClientValidationRules()
    {
        if (!this.ShouldGenerateClientSideRules())
        {
            yield break;
        }
        var validator = Validator as LessThanOrEqualValidator;
        var errorMessage = new MessageFormatter()
            .AppendPropertyName(this.Rule.GetDisplayName())
            .BuildMessage(validator.ErrorMessageSource.GetString());
        var rule = new ModelClientValidationRule
        {
            ErrorMessage = errorMessage,
            ValidationType = "lessthanorequaldate"
        };
        rule.ValidationParameters["other"] = CompareAttribute.FormatPropertyForClientValidation(validator.MemberToCompare.Name);
        yield return rule;
    }
}

当配置我们的FluentValidation提供商：时，它将在Application_Start中注册

FluentValidationModelValidatorProvider.Configure(x =>
{
    x.Add(typeof(LessThanOrEqualValidator), (metadata, context, rule, validator) => new LessThanOrEqualToFluentValidationPropertyValidator(metadata, context, rule, validator));
});

最后一位是客户端上的自定义适配器。因此，我们当然在页面中添加了两个脚本，以实现不引人注目的客户端验证：

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

和自定义适配器：

(function ($) {
    $.validator.unobtrusive.adapters.add('lessthanorequaldate', ['other'], function (options) {
        var getModelPrefix = function (fieldName) {
            return fieldName.substr(0, fieldName.lastIndexOf(".") + 1);
        };
        var appendModelPrefix = function (value, prefix) {
            if (value.indexOf("*.") === 0) {
                value = value.replace("*.", prefix);
            }
            return value;
        }
        var prefix = getModelPrefix(options.element.name),
            other = options.params.other,
            fullOtherName = appendModelPrefix(other, prefix),
            element = $(options.form).find(":input[name=" + fullOtherName + "]")[0];
        options.rules['lessthanorequaldate'] = element;
        if (options.message != null) {
            options.messages['lessthanorequaldate'] = options.message;
        }
    });
    $.validator.addMethod('lessthanorequaldate', function (value, element, params) {
        var parseDate = function (date) {
            var m = date.match(/^('d{4})-('d{1,2})-('d{1,2})$/);
            return m ? new Date(parseInt(m[1]), parseInt(m[2]) - 1, parseInt(m[3])) : null;
        };
        var date = parseDate(value);
        var dateToCompareAgainst = parseDate($(params).val());
        if (isNaN(date.getTime()) || isNaN(dateToCompareAgainst.getTime())) {
            return false;
        }
        return date <= dateToCompareAgainst;
    });
})(jQuery);

Darin的例子中有一些过时的东西，所以这里有一个更更新的例子，可以进行数字比较。不过，你可以很容易地调整它进行日期比较：

Javascript：

(function ($)
{
    $.validator.addMethod("lessthanorequal", function(value, element, param)
    {
        return this.optional(element) || parseFloat(value) <= parseFloat(param);
    }, "Must be less than");
    $.validator.unobtrusive.adapters.add("lessthanorequal", ["field"], function (options)
    {
        options.rules["lessthanorequal"] = options.params.field;
        if (options.message) options.messages["lessthanorequal"] = options.message;
    });
})(jQuery);

C#

public class LessThanOrEqualPropertyValidator : FluentValidationPropertyValidator
{
    public LessThanOrEqualPropertyValidator(ModelMetadata metadata, ControllerContext controllerContext, PropertyRule rule, IPropertyValidator validator)
        : base(metadata, controllerContext, rule, validator)
    {
    }
    public override IEnumerable<ModelClientValidationRule> GetClientValidationRules()
    {
        if (!ShouldGenerateClientSideRules()) yield break;
        var formatter = new MessageFormatter().AppendPropertyName(Rule.PropertyName);
        string message = formatter.BuildMessage(Validator.ErrorMessageSource.GetString());
        var rule = new ModelClientValidationRule
        {
            ValidationType = "lessthanorequal",
            ErrorMessage = message
        };
         rule.ValidationParameters["field"] =  ((LessThanOrEqualValidator)Validator).ValueToCompare;
        yield return rule;
    }
}

Global.asax应用程序启动：

FluentValidation.Mvc.FluentValidationModelValidatorProvider.Configure(x =>
{
    x.Add(typeof(LessThanOrEqualValidator), (metadata, context, description, validator) => new LessThanOrEqualPropertyValidator(metadata, context, description, validator));
});

因此，现在任何使用LessThanOrEqual的数字规则都将在客户端进行验证。

LessThanOrEqualTo和GreaterThanOrEqualTo不支持开箱即用的客户端验证。

但是，支持InclusiveBetween。所以你可以使用InclusiveBetween。

示例

RuleFor(x => x.StartDate)
    .InclusiveBetween(x.AbsoluteStartDate, x.AbsoluteEndDate)

有关支持的客户端方法的更多信息，请参阅文档。