13

我有一个自定义模型类，其中包含一个小数成员和一个接受此类条目的视图。在我添加 javascripts 来格式化输入控件中的数字之前，一切都运行良好。格式代码在焦点模糊时用千位分隔符'，'格式化输入的数字。

问题是我的模态类中的十进制值没有用千位分隔符很好地绑定/解析。当我使用“1,000.00”对其进行测试时，ModelState.IsValid 返回 false，但它对“100.00”有效，没有任何更改。

如果您对此有任何解决方案，可以与我分享吗？

提前致谢。

样本类

public class Employee
{
    public string Name { get; set; }
    public decimal Salary { get; set; }
}

样品控制器

public class EmployeeController : Controller
{
    [AcceptVerbs(HttpVerbs.Get)]
    public ActionResult New()
    {
        return View();
    }

    [AcceptVerbs(HttpVerbs.Post)]
    public ActionResult New(Employee e)
    {
        if (ModelState.IsValid) // <-- It is retruning false for values with ','
        {
            //Subsequence codes if entry is valid.
            //
        }
        return View(e);
    }
}

示例视图

<% using (Html.BeginForm())
   { %>

    Name:   <%= Html.TextBox("Name")%><br />
    Salary: <%= Html.TextBox("Salary")%><br />

    <button type="submit">Save</button>

<% } %>

正如 Alexander 建议的那样，我尝试了使用 Custom ModelBinder 的解决方法。问题解决了。但该解决方案与 IDataErrorInfo 实现并不顺利。由于验证，当输入 0 时，Salary 值变为空。请问有什么建议吗？Asp.Net MVC 团队成员会来 stackoverflow 吗？我能从你那里得到一点帮助吗？

按照 Alexander 的建议，使用自定义模型绑定器更新了代码

模型粘合剂

public class MyModelBinder : DefaultModelBinder {

    public override object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext) {
        if (bindingContext == null) {
            throw new ArgumentNullException("bindingContext");
        }

        ValueProviderResult valueResult;
        bindingContext.ValueProvider.TryGetValue(bindingContext.ModelName, out valueResult);
        if (valueResult != null) {
            if (bindingContext.ModelType == typeof(decimal)) {
                decimal decimalAttempt;

                decimalAttempt = Convert.ToDecimal(valueResult.AttemptedValue);

                return decimalAttempt;
            }
        }
        return null;
    }
}

员工类

    public class Employee : IDataErrorInfo {

    public string Name { get; set; }
    public decimal Salary { get; set; }

    #region IDataErrorInfo Members

    public string this[string columnName] {
        get {
            switch (columnName)
            {
                case "Salary": if (Salary <= 0) return "Invalid salary amount."; break;
            }
            return string.Empty;
        }
    }

    public string Error{
        get {
            return string.Empty;
        }
    }

    #endregion
}
4

6 回答 6

15

其背后的原因是，在 ValueProviderResult.cs 的 ConvertSimpleType 中使用了 TypeConverter。

十进制的 TypeConverter 不支持千位​​分隔符。在这里阅读：http ://social.msdn.microsoft.com/forums/en-US/clr/thread/1c444dac-5d08-487d-9369-666d1b21706e

我还没有检查，但在那篇文章中，他们甚至说没有使用传递给 TypeConverter 的 CultureInfo。它永远是不变的。

           string decValue = "1,400.23";

        TypeConverter converter = TypeDescriptor.GetConverter(typeof(decimal));
        object convertedValue = converter.ConvertFrom(null /* context */, CultureInfo.InvariantCulture, decValue);

所以我想你必须使用一种解决方法。不太好...

于 2009-06-16T08:35:59.710 回答
7

我不喜欢上面的解决方案并想出了这个：

在我的自定义模型绑定器中，如果它是小数，我基本上将值替换为文化不变值，然后将其余工作交给默认模型绑定器。作为一个数组的 rawvalue 对我来说似乎很奇怪，但这是我在原始代码中看到/偷来的。

        public override object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
    {
        if(bindingContext.ModelType == typeof(decimal) || bindingContext.ModelType==typeof(Nullable<decimal>))
        {
            ValueProviderResult valueProviderResult = bindingContext.ValueProvider[bindingContext.ModelName];
            if (valueProviderResult != null)
            {
                decimal result;
                var array = valueProviderResult.RawValue as Array;
                object value;
                if (array != null && array.Length > 0)
                {
                    value = array.GetValue(0);
                    if (decimal.TryParse(value.ToString(), out result))
                    {
                        string val = result.ToString(CultureInfo.InvariantCulture.NumberFormat);
                        array.SetValue(val, 0);
                    }
                }
            }
        }
        return base.BindModel(controllerContext, bindingContext);
    }
于 2009-08-21T21:20:46.563 回答
4

似乎总是可以找到某种形式的解决方法，以使默认模型绑定器满意！我想知道您是否可以创建一个仅由模型绑定器使用的“伪”属性？（注意，这绝不是优雅的。我自己，我似乎越来越频繁地诉诸类似的技巧，因为它们有效并且他们“完成”了工作......）另请注意，如果您使用单独的“ViewModel”（我为此推荐），你可以把这段代码放在那里，让你的域模型干净整洁。

public class Employee
{
    private decimal _Salary;
    public string MvcSalary // yes, a string. Bind your form values to this!
    {
        get { return _Salary.ToString(); }
        set
        { 
            // (Using some pseudo-code here in this pseudo-property!)
            if (AppearsToBeValidDecimal(value)) {
                _Salary = StripCommas(value);
            }
        }
    }
    public decimal Salary
    {
        get { return _Salary; }
        set { _Salary = value; }
    }
}

PS，我打了这个之后，现在回头看，甚至犹豫要不要发这个，太丑了！但是，如果您认为这可能会有所帮助，我会让您决定...

祝你好运！
-麦克风

于 2009-06-18T00:12:14.930 回答
0

您是否尝试在控制器中将其转换为十进制？这应该可以解决问题：

字符串_val =“1,000.00”；十进制 _decVal = Convert.ToDecimal(_val); Console.WriteLine(_decVal.ToString());

于 2009-06-16T07:57:58.790 回答
0

嘿，我还有一个想法……这建立在 Naweed 的回答之上，但仍然可以让您使用默认的模型绑定器。概念是截取已发布的表单，修改其中的一些值，然后将 [修改] 表单集合传递给 UpdateModel（默认模型绑定器）方法...我使用它的修改版本来处理复选框/布尔值, 以避免“真”或“假”以外的任何内容在模型绑定器中导致未处理/静默异常的情况。

（您当然希望将其重构为更可重用，以处理所有小数）

public ActionResult myAction(NameValueCollection nvc)
{
    Employee employee = new Employee();
    string salary = nvc.Get("Salary");
    if (AppearsToBeValidDecimal(salary)) {
        nvc.Remove("Salary");
        nvc.Add("Salary", StripCommas(salary));
    }
    if (TryUpdateModel(employee, nvc)) {
        // ...
    }
}

PS，我可能对我的 NVC 方法感到困惑，但我认为这些方法会奏效。

于 2009-06-18T04:55:29.540 回答
0

我实现了自定义验证器，增加了分组的有效性。问题（我在下面的代码中解决）是 parse 方法删除了所有千位分隔符，因此 1,2,2 也被认为是有效的。

这是我的十进制活页夹

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using System.Web.Mvc;

namespace EA.BUTruck.ContactCenter.Model.Extensions
{
 public class DecimalModelBinder : IModelBinder
 {
    public object BindModel(ControllerContext controllerContext,
        ModelBindingContext bindingContext)
    {
        ValueProviderResult valueResult = bindingContext.ValueProvider
            .GetValue(bindingContext.ModelName);
        ModelState modelState = new ModelState { Value = valueResult };
        object actualValue = null;
        try
        {
            var trimmedvalue = valueResult.AttemptedValue.Trim();
            actualValue = Decimal.Parse(trimmedvalue, CultureInfo.CurrentCulture);

            string decimalSep = CultureInfo.CurrentCulture.NumberFormat.NumberDecimalSeparator;
            string thousandSep = CultureInfo.CurrentCulture.NumberFormat.NumberGroupSeparator;

            thousandSep = Regex.Replace(thousandSep, @"\u00A0", " "); //used for culture with non breaking space thousand separator

            if (trimmedvalue.IndexOf(thousandSep) >= 0)
            {
                //check validity of grouping thousand separator

                //remove the "decimal" part if exists
                string integerpart = trimmedvalue.Split(new string[] { decimalSep }, StringSplitOptions.None)[0];

                //recovert double value (need to replace non breaking space with space present in some cultures)
                string reconvertedvalue = Regex.Replace(((decimal)actualValue).ToString("N").Split(new string[] { decimalSep }, StringSplitOptions.None)[0], @"\u00A0", " ");
                //if are the same, it is a valid number
                if (integerpart == reconvertedvalue)
                    return actualValue;

                //if not, could be differences only in the part before first thousand separator (for example original input stirng could be +1.000,00 (example of italian culture) that is valid but different from reconverted value that is 1.000,00; so we need to make a more accurate checking to verify if input string is valid


                //check if number of thousands separators are the same
                int nThousands = integerpart.Count(x => x == thousandSep[0]);
                int nThousandsconverted = reconvertedvalue.Count(x => x == thousandSep[0]);

                if (nThousands == nThousandsconverted)
                {
                    //check if all group are of groupsize number characters (exclude the first, because could be more than 3 (because for example "+", or "0" before all the other numbers) but we checked number of separators == reconverted number separators
                    int[] groupsize = CultureInfo.CurrentCulture.NumberFormat.NumberGroupSizes;
                    bool valid = ValidateNumberGroups(integerpart, thousandSep, groupsize);
                    if (!valid)
                        throw new FormatException();

                }
                else
                    throw new FormatException();

            }


        }
        catch (FormatException e)
        {
            modelState.Errors.Add(e);
        }

        bindingContext.ModelState.Add(bindingContext.ModelName, modelState);
        return actualValue;
    }
    private bool ValidateNumberGroups(string value, string thousandSep, int[] groupsize)
    {
        string[] parts = value.Split(new string[] { thousandSep }, StringSplitOptions.None);
        for (int i = parts.Length - 1; i > 0; i--)
        {
            string part = parts[i];
            int length = part.Length;
            if (groupsize.Contains(length) == false)
            {
                return false;
            }
        }

        return true;
    }
 }
}

对于十进制？可以为空你需要在之前添加一些代码

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Globalization;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using System.Web.Mvc;

namespace EA.BUTruck.ContactCenter.Model.Extensions
{
 public class DecimalNullableModelBinder : IModelBinder
 {
    public object BindModel(ControllerContext controllerContext,
        ModelBindingContext bindingContext)
    {
        ValueProviderResult valueResult = bindingContext.ValueProvider
            .GetValue(bindingContext.ModelName);
        ModelState modelState = new ModelState { Value = valueResult };
        object actualValue = null;
        try
        {
             //need this condition against non nullable decimal
             if (string.IsNullOrWhiteSpace(valueResult.AttemptedValue))
                return actualValue;
            var trimmedvalue = valueResult.AttemptedValue.Trim();
            actualValue = Decimal.Parse(trimmedvalue,CultureInfo.CurrentCulture);

            string decimalSep = CultureInfo.CurrentCulture.NumberFormat.NumberDecimalSeparator;
            string thousandSep = CultureInfo.CurrentCulture.NumberFormat.NumberGroupSeparator;

            thousandSep = Regex.Replace(thousandSep, @"\u00A0", " "); //used for culture with non breaking space thousand separator

            if (trimmedvalue.IndexOf(thousandSep) >=0)
            {
                //check validity of grouping thousand separator

                //remove the "decimal" part if exists
                string integerpart = trimmedvalue.Split(new string[] { decimalSep }, StringSplitOptions.None)[0];

                //recovert double value (need to replace non breaking space with space present in some cultures)
                string reconvertedvalue = Regex.Replace(((decimal)actualValue).ToString("N").Split(new string[] { decimalSep }, StringSplitOptions.None)[0], @"\u00A0", " ");
                //if are the same, it is a valid number
                if (integerpart == reconvertedvalue)
                    return actualValue;

                //if not, could be differences only in the part before first thousand separator (for example original input stirng could be +1.000,00 (example of italian culture) that is valid but different from reconverted value that is 1.000,00; so we need to make a more accurate checking to verify if input string is valid


                //check if number of thousands separators are the same
                int nThousands = integerpart.Count(x => x == thousandSep[0]);
                int nThousandsconverted = reconvertedvalue.Count(x => x == thousandSep[0]);

                if(nThousands == nThousandsconverted)
                {
                    //check if all group are of groupsize number characters (exclude the first, because could be more than 3 (because for example "+", or "0" before all the other numbers) but we checked number of separators == reconverted number separators
                    int[] groupsize = CultureInfo.CurrentCulture.NumberFormat.NumberGroupSizes;
                    bool valid = ValidateNumberGroups(integerpart, thousandSep, groupsize);
                    if (!valid)
                        throw new FormatException();

                }
                else
                    throw new FormatException();

            }


        }
        catch (FormatException e)
        {
            modelState.Errors.Add(e);
        }

        bindingContext.ModelState.Add(bindingContext.ModelName, modelState);
        return actualValue;
    }

    private bool ValidateNumberGroups(string value, string thousandSep, int[] groupsize)
    {
        string[] parts = value.Split(new string[] { thousandSep }, StringSplitOptions.None);
        for(int i = parts.Length-1; i > 0; i--)
        {
            string part = parts[i];
            int length = part.Length;
            if (groupsize.Contains(length) == false)
            {
                return false;
            }
        }

        return true;
    }
 }

}

您需要为 double、double?、float、float 创建类似的活页夹？（代码与 DecimalModelBinder 和 DecimalNullableModelBinder 相同；您只需在有“十进制”的 2 点替换类型）。

然后在 global.asax

ModelBinders.Binders.Add(typeof(decimal), new DecimalModelBinder());
ModelBinders.Binders.Add(typeof(decimal?), new DecimalNullableModelBinder());
ModelBinders.Binders.Add(typeof(float), new FloatModelBinder());
ModelBinders.Binders.Add(typeof(float?), new FloatNullableModelBinder());
ModelBinders.Binders.Add(typeof(double), new DoubleModelBinder());
ModelBinders.Binders.Add(typeof(double?), new DoubleNullableModelBinder());

该解决方案在服务器端运行良好，例如使用 jquery globalize 的客户端部分，我的修复报告在这里 https://github.com/globalizejs/globalize/issues/73#issuecomment-275792643

于 2017-01-29T01:25:51.427 回答