Question

我们说我有这种观点模型：


    public class MyModel
    {
        [Range(0, 999, ErrorMessage = "Invalid quantity")]
        public int Quantity { get; set; }
    }

现在，对于此模型的特定实例，有效值的范围将更改：某些值可能不会为0，有些值可能不会高于5.有效范围的最小值/最大值来自数据库并且可能会更改任何时候。

如何动态更改RangeAttribute的最小/最大属性？或者它是验证我的场景的最佳方式是什么？

Answer 1

有些事情可能更像是你的事后......

视图模型：

public class ViewModel
{
    public DateTime MinDate {get; set;}
    public DateTime MaxDate {get; set;}

    [DynamicRange("MinDate", "MaxDate", ErrorMessage = "Value must be between {0} and {1}")]
    public DateTime Date{ get; set; }
}

图书馆班级或其他地方：

public class DynamicRange : ValidationAttribute, IClientValidatable
    {
        private readonly string _minPropertyName;
        private readonly string _maxPropertyName;

    public DynamicRange(string minPropName, string maxPropName)
    {
        _minPropertyName = minPropName;
        _maxPropertyName = maxPropName;
    }

    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));

        var minValue = (int) minProperty.GetValue(validationContext.ObjectInstance, null);
        var maxValue = (int) maxProperty.GetValue(validationContext.ObjectInstance, null);

        var 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 = ErrorMessage
            };

        rule.ValidationParameters["minvalueproperty"] = _minPropertyName;
        rule.ValidationParameters["maxvalueproperty"] = _maxPropertyName;
        yield return rule;
    }

来自：MVC unobtrusive range validation of dynamic values

Answer 2

我认为您最好的选择可能是为您的特定模型（MyModel）实现自定义模型绑定器。你可以拥有的是这样的东西：

public class MyModel
{
    public int Quantity { get; set; }
} // unchanged Model

public class MyViewModel
{
    public MyModel myModel { get; set; }
    public int QuantityMin { get; set; }
    public int QuantityMax { get; set; }
}

然后您可以设置这些值，并在自定义模型活页夹中，您可以将myModel.Quantity属性与QuantityMin和QuantityMax属性进行比较。

实施例

<强>模型：

public class QuantityModel
{
    public int Quantity { get; set; }
}

<强> VIEWMODE ：

public class QuantityViewModel
{
    public QuantityModel quantityModel { get; set; }
    public int QuantityMin { get; set; }
    public int QuantityMax { get; set; }
}

自定义模型Binder ：

public class VarQuantity : IModelBinder
{
    public object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
    {
        int MinValue = Convert.ToInt32(bindingContext.ValueProvider.GetValue("QuantityMin").AttemptedValue);
        int MaxValue = Convert.ToInt32(bindingContext.ValueProvider.GetValue("QuantityMax").AttemptedValue);
        int QuantityValue = Convert.ToInt32(bindingContext.ValueProvider.GetValue("quantityModel.Quantity").AttemptedValue);

        if (!(QuantityValue >= MinValue && QuantityValue <= MaxValue))
            bindingContext.ModelState.AddModelError("Quantity", "Quantity not between values");

        return bindingContext.Model;
    }
}

注册自定义模型Binder ：

ModelBinders.Binders.Add(typeof(QuantityViewModel), new VarQuantity());

测试控制器操作方法：

    public ActionResult Quantity()
    {
        return View();
    }

    [HttpPost]
    public string Quantity(QuantityViewModel qvm)
    {
        if (ModelState.IsValid)
            return "Valid!";
        else
            return "Invalid!";
    }

测试查看代码：

@model MvcTest.Models.QuantityViewModel

<h2>Quantity</h2>

@using (Html.BeginForm())
{
    @Html.Label("Enter Your Quantity: ")
    @Html.TextBoxFor(m => m.quantityModel.Quantity)
    <br />
    @Html.Label("Quantity Minimum: ")
    @Html.TextBoxFor(m => m.QuantityMin)
    <br />
    @Html.Label("Quantity Maximum: ")
    @Html.TextBoxFor(m => m.QuantityMax)
    <br /><br />
    <input type="submit" value="Submit" />
}

以编程方式更改验证范围（MVC3 ASP.NET）

2 个答案:

实施例