Fluent Validation不接受带有千位分隔符的数字

Question

我有一个使用Fluent Validation for MVC 5的ASP.NET MVC 5项目.我还使用jQuery masking插件自动添加数千个双值.

在模型中我有:

    [Display(Name = "Turnover")]
    [DisplayFormat(ApplyFormatInEditMode = true,ConvertEmptyStringToNull =true,DataFormatString ="#,##0")]
    public double? Turnover { get; set; }

在视图中我有:

<th class="col-xs-2">
    @Html.DisplayNameFor(model=>model.Turnover)
</th>
<td class="col-xs-4">
    @Html.TextBoxFor(model => model.Turnover, new { @class = "form-control number", placeholder="Enter number. Thousands added automatically" })
</td>
<td class="col-xs-6">
    @Html.ValidationMessageFor(model => model.Turnover, "", new { @class = "text-danger" })
</td>

为包含模型定义了一个流畅的验证器,但它不包含任何规则.我只使用服务器端验证.

public class MyModelValidator: AbstractValidator<MyModel>
{
    public MyModelValidator()
    {

    }
}

不幸的是,我得到了营业额的验证错误如下:

我尝试使用模型绑定来解决这个问题.但是模型绑定器的断点永远不会受到打击 - 流畅的验证似乎阻止了达到模型绑定器的价值.

Answer 1

几件事情要提到:

• 该问题与Fluent验证没有任何共同之处.无论有没有Fluent验证,我都能够重现/修复它.
• 在DataFormatString使用不正确(缺少值占位符).它应该是真的"{0:#,##0}".
• 链接的ModelBinder方法实际上是有效的.我猜你忘了它是为数据类型编写的,而你的模型正在使用,所以你必须编写并注册另一个和类型.decimaldouble?doubledouble?

现在关于这个问题.实际上有两种解决方案.它们都使用以下辅助类进行实际的字符串转换:

using System;
using System.Collections.Generic;
using System.Globalization;

public static class NumericValueParser
{
    static readonly Dictionary<Type, Func<string, CultureInfo, object>> parsers = new Dictionary<Type, Func<string, CultureInfo, object>>
    {
        { typeof(byte), (s, c) => byte.Parse(s, NumberStyles.Any, c) },
        { typeof(sbyte), (s, c) => sbyte.Parse(s, NumberStyles.Any, c) },
        { typeof(short), (s, c) => short.Parse(s, NumberStyles.Any, c) },
        { typeof(ushort), (s, c) => ushort.Parse(s, NumberStyles.Any, c) },
        { typeof(int), (s, c) => int.Parse(s, NumberStyles.Any, c) },
        { typeof(uint), (s, c) => uint.Parse(s, NumberStyles.Any, c) },
        { typeof(long), (s, c) => long.Parse(s, NumberStyles.Any, c) },
        { typeof(ulong), (s, c) => ulong.Parse(s, NumberStyles.Any, c) },
        { typeof(float), (s, c) => float.Parse(s, NumberStyles.Any, c) },
        { typeof(double), (s, c) => double.Parse(s, NumberStyles.Any, c) },
        { typeof(decimal), (s, c) => decimal.Parse(s, NumberStyles.Any, c) },
    };

    public static IEnumerable<Type> Types { get { return parsers.Keys; } }

    public static object Parse(string value, Type type, CultureInfo culture)
    {
        return parsers[type](value, culture);
    }
}

习惯 IModelBinder

这是链接方法的修改版本.它是一个处理所有数字类型及其各自可空类型的类:

using System;
using System.Web.Mvc;

public class NumericValueBinder : IModelBinder
{
    public static void Register()
    {
        var binder = new NumericValueBinder();
        foreach (var type in NumericValueParser.Types)
        {
            // Register for both type and nullable type
            ModelBinders.Binders.Add(type, binder);
            ModelBinders.Binders.Add(typeof(Nullable<>).MakeGenericType(type), binder);
        }
    }

    private NumericValueBinder() { }

    public object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
    {
        var valueResult = bindingContext.ValueProvider.GetValue(bindingContext.ModelName);
        var modelState = new ModelState { Value = valueResult };
        object actualValue = null;
        if (!string.IsNullOrWhiteSpace(valueResult.AttemptedValue))
        {
            try
            {
                var type = bindingContext.ModelType;
                var underlyingType = Nullable.GetUnderlyingType(type);
                var valueType = underlyingType ?? type;
                actualValue = NumericValueParser.Parse(valueResult.AttemptedValue, valueType, valueResult.Culture);
            }
            catch (Exception e)
            {
                modelState.Errors.Add(e);
            }
        }
        bindingContext.ModelState.Add(bindingContext.ModelName, modelState);
        return actualValue;
    }
}

您只需在以下位置注册Application_Start:

protected void Application_Start()
{
    NumericValueBinder.Register();  
    // ...
}

习惯 TypeConverter

这不是特定于ASP.NET MVC 5,而是DefaultModelBinder将字符串转换委托给关联的TypeConverter(类似于其他.NET UI框架).事实上,问题是由于TypeConverter数字类型的默认类不使用Convert类,但是传递的Parse重载排除了. NumberStylesNumberStyles.FloatNumberStyles.AllowThousands

幸运的是,System.ComponentModel它提供了可扩展的类型描述符体系结构,允许您关联自定义TypeConverter.管道部分有点复杂(您必须注册一个自定义TypeDescriptionProvider以提供ICustomTypeDescriptor最终返回自定义的实现TypeConverter),但是在提供的基类的帮助下,将大部分内容委托给底层对象,实现看起来像这样:

using System;
using System.ComponentModel;
using System.Globalization;

class NumericTypeDescriptionProvider : TypeDescriptionProvider
{
    public static void Register()
    {
        foreach (var type in NumericValueParser.Types)
            TypeDescriptor.AddProvider(new NumericTypeDescriptionProvider(type, TypeDescriptor.GetProvider(type)), type);
    }

    readonly Descriptor descriptor;

    private NumericTypeDescriptionProvider(Type type, TypeDescriptionProvider baseProvider)
        : base(baseProvider)
    {
        descriptor = new Descriptor(type, baseProvider.GetTypeDescriptor(type));
    }

    public override ICustomTypeDescriptor GetTypeDescriptor(Type objectType, object instance)
    {
        return descriptor;
    }

    class Descriptor : CustomTypeDescriptor
    {
        readonly Converter converter;
        public Descriptor(Type type, ICustomTypeDescriptor baseDescriptor)
            : base(baseDescriptor)
        {
            converter = new Converter(type, baseDescriptor.GetConverter());
        }
        public override TypeConverter GetConverter()
        {
            return converter;
        }
    }

    class Converter : TypeConverter
    {
        readonly Type type;
        readonly TypeConverter baseConverter;
        public Converter(Type type, TypeConverter baseConverter)
        {
            this.type = type;
            this.baseConverter = baseConverter;
        }
        public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)
        {
            return baseConverter.CanConvertTo(context, destinationType);
        }
        public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType)
        {
            return baseConverter.ConvertTo(context, culture, value, destinationType);
        }
        public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType)
        {
            return baseConverter.CanConvertFrom(context, sourceType);
        }
        public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value)
        {
            if (value is string)
            {
                try { return NumericValueParser.Parse((string)value, type, culture); }
                catch { }
            }
            return baseConverter.ConvertFrom(context, culture, value);
        }
    }
}

(是的,为了添加一条基本行,很多样板代码!从另一方面来说,没有必要处理可空类型,因为DefaultModelBinder已经这样做:)

与第一种方法类似,您只需要注册它:

protected void Application_Start()
{
    NumericTypeDescriptionProvider.Register();  
    // ...
}