asp.net-mvc – MVC不引人注目的范围验证动态值

public class RangeValidationSampleModel
{
    int Value { get; set; }

    int MinValue { get; set; }

    int MaxValue { get; set; }
}

您可以为此编写自定义验证属性：

public class DynamicRangeValidator : ValidationAttribute,IClientValidatable
{
    private readonly String _minPropertyName;
    private readonly String _maxPropertyName;
    public DynamicRangeValidator(String minPropertyName,String maxPropertyName)
    {
        _minPropertyName = minPropertyName;
        _maxPropertyName = maxPropertyName;
    }

    protected override ValidationResult IsValid(object value,ValidationContext validationContext)
    {
        var minProperty = validationContext.objectType.GetProperty(_minPropertyName);
        var maxProperty = validationContext.objectType.GetProperty(_maxPropertyName);
        if (minProperty == null)
        {
            return new ValidationResult(String.Format("Unknown property {0}",_minPropertyName));
        }
        if (maxProperty == null)
        {
            return new ValidationResult(String.Format("Unknown property {0}",_maxPropertyName));
        }

        int minValue = (int)R_151_11845@inProperty.GetValue(validationContext.objecTinstance,null);
        int maxValue = (int)R_151_11845@axProperty.GetValue(validationContext.objecTinstance,null);
        int currentValue = (int)value;
        if (currentValue <= minValue || currentValue >= maxvalue)
        {
            return new ValidationResult(
                String.Format(
                    Errormessage,minValue,maxValue
                )
            );
        }

        return null;
    }

    public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata,ControllerContext context)
    {
        var rule = new ModelClientValidationRule
        {
            ValidationType = "dynamicrange",Errormessage = this.Errormessage,};
        rule.ValidationParameters["minvalueproperty"] = _minPropertyName;
        rule.ValidationParameters["maxvalueproperty"] = _maxPropertyName;
        yield return rule;
    }
}

然后用它来装饰你的视图模型：

public class RangeValidationSampleModel
{
    [DynamicRangeValidator("MinValue","MaxValue",Errormessage = "Value must be between {0} and {1}")]
    public int Value { get; set; }
    public int MinValue { get; set; }
    public int MaxValue { get; set; }
}

那么你可以有一个控制器提供视图：

public class HomeController : Controller
{
    public ActionResult Index()
    {
        return View(new RangeValidationSampleModel
        {
            Value = 5,MinValue = 6,MaxValue = 8
        });
    }

    [httpPost]
    public ActionResult Index(RangeValidationSampleModel model)
    {
        return View(model);
    }
}

并且当然是：

@model RangeValidationSampleModel

<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>
<script type="text/javascript">
    $.validator.unobtrusive.adapters.add('dynamicrange',['minvalueproperty','maxvalueproperty'],function (options) {
            options.rules['dynamicrange'] = options.params;
            if (options.message != null) {
                $.validator.messages.dynamicrange = options.message;
            }
        }
    );

    $.validator.addMethod('dynamicrange',function (value,element,params) {
        var minValue = parseInt($('input[name="' + params.minvalueproperty + '"]').val(),10);
        var maxValue = parseInt($('input[name="' + params.maxvalueproperty + '"]').val(),10);
        var currentValue = parseInt(value,10);
        if (isNaN(minvalue) || isNaN(maxvalue) || isNaN(currentvalue) || minValue >= currentValue || currentValue >= maxvalue) {
            var message = $(element).attr('data-val-dynamicrange');
            $.validator.messages.dynamicrange = $.validator.format(message,maxvalue);
            return false;
        }
        return true;
    },'');
</script>

@using (Html.beginForm())
{
    <div>
        @Html.LabelFor(x => x.value)
        @Html.EditorFor(x => x.value)
        @Html.ValidationmessageFor(x => x.value)
    </div>
    <div>
        @Html.LabelFor(x => x.Minvalue)
        @Html.EditorFor(x => x.Minvalue)
    </div>
    <div>
        @Html.LabelFor(x => x.Maxvalue)
        @Html.EditorFor(x => x.Maxvalue)
    </div>
    <button type="submit">OK</button>
}

显然，自定义适配器注册应该在一个外部的javascript文件中执行，以避免污染视图，但为了这个目的和简洁的这篇文章我把它放在视图内。