c# – MVC3 LowerCase路由值的行为与UpperCase不同？

在这里为很多代码道歉……我试图尽可能地保持它：

我写了(主要是从这里偷来的)一个HtmlHelper扩展来写出一个基于枚举的RadioButton(分组).我还设置了路线图,因此它使用枚举而不是“id”等.

我有两个枚举(对于此示例)CurrencyType和StatusType

当我调用URL / GBP / Open时,我的HtmlHelper正常工作并设置单选按钮的值,并选中GBP和Open.

当我调用URL / gbp / open时 – Helper仍会检查值并且似乎工作…但是当调用RadioButton().ToHtmlString()时,“checked”不存在????
使用默认路由,单选按钮仍然正确设置???

如果您断开返回的SelectList,那么您可以看到所选的选项设置正确,所以我对问题出现的地方有点难过？

Empty MVC3 website called Area36...Area 51 was taken ;)


using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using System.Web.Mvc.Html;
using System.Linq.Expressions;
using System.Text;

namespace Area36.Models
{
    public static class Extensions
    {
        public static SelectList ToSelectList<TEnum>(this TEnum enumObj)
        {
            var values = from TEnum e in Enum.GetValues(typeof(TEnum))
                         select new { ID = e,Name = e };
            return new SelectList(values,"Id","Name",enumObj);
        }

        public static void AppendFormatLine(this StringBuilder sb,string format,params object[] args)
        {
            sb.AppendFormat(format,args);
            sb.AppendLine();
        }

        public static MvcHtmlString RadioButtonForEnum<TModel,TProperty>(this HtmlHelper<TModel> htmlHelper,Expression<Func<TModel,TProperty>> expression,string fieldSet)
        {
            var MetaData = ModelMetadata.FromLambdaExpression(expression,htmlHelper.ViewData);
            var e = (TProperty)Enum.Parse(typeof(TProperty),MetaData.Model.ToString());
            var selectList = e.ToSelectList();
            var sb = new StringBuilder();

            if (selectList != null)
            {
                sb.AppendFormatLine("<fieldset><legend>{0}</legend>",fieldSet);
                foreach (SelectListItem item in selectList)
                {
                    var id = string.Format("{0}_{1}",MetaData.PropertyName,item.Value);
                    if (htmlHelper.ViewData.TemplateInfo.HtmlFieldPrefix != string.Empty)
                        id.Insert(0,string.Format("{0}_",htmlHelper.ViewData.TemplateInfo.HtmlFieldPrefix));

                    var label = htmlHelper.Label(id,HttpUtility.HtmlEncode(item.Text));
                    var radio = htmlHelper.RadioButton(name: MetaData.PropertyName,value: item.Value,isChecked: item.Selected,htmlAttributes: new { id = id }).ToHtmlString();

                    sb.AppendFormatLine("<div class=\"radio_{0}\">{1}{2}</div>",radio,label);
                }
                sb.AppendLine("</fieldset>");
            }

            return MvcHtmlString.Create(sb.ToString());
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using Area36.Models;

namespace Area36.Controllers
{
    public class HomeController : Controller
    {
        //
        // GET: /Home/

        public ActionResult Index(CurrencyType currency,StatusType status)
        {
            return View(new viewmodel { Currency = currency,Status = status });
        }

    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

namespace Area36.Models
{
    public class viewmodel
    {
        public CurrencyType Currency { get; set; }
        public StatusType Status { get; set; }
    }
}

@using Area36.Models
@model Area36.Models.viewmodel


@{
    ViewBag.Title = "Index";
}

<h2>Index</h2>
@Html.RadioButtonForEnum(m => m.Currency,"Currency")
@Html.RadioButtonForEnum(m => m.Status,"Status")

public static void RegisterRoutes(RouteCollection routes)
        {
            routes.IgnoreRoute("{resource}.axd/{*pathInfo}");

            routes.MapRoute(
                "Default",// Route name
                "{currency}/{status}",// URL with parameters
                new { controller = "Home",action = "Index",currency = CurrencyType.EUR,status = StatusType.Closed} // Parameter defaults
            );

        }

解决方法

我尝试了各种方案来解决这个问题.强有力地传递了UpperCase值.最令人惊讶的是,当我为所有单选按钮传递’true’时,如下所示,即使输出相同,也只检查按钮的大写url.

var radio = htmlHelper.RadioButton(MetaData.PropertyName,item.Value,true,new { id = id }).ToHtmlString();

随着一些rnd与这个代码和一些谷歌搜索我发现this.
如果你检查
以下是MVC3-rtm的代码.在这里你可以看到isChecked的值是根据ModelState修改的,如果在调试模式下检查modelState.Values [index] .AttemptedValue的值,它显然是小写的(对于“gbp / open”).这就是小写url不呈现checked属性的原因.

private IHtmlString buildradioButton(string name,object value,bool? isChecked,IDictionary<string,object> attributes) {
        string valueString = ConvertTo(value,typeof(string)) as string;

        TagBuilder builder = new TagBuilder("input");
        builder.MergeAttribute("type","radio",true);
        builder.GenerateId(name);
        builder.MergeAttributes(attributes,replaceExisting: true);

        builder.MergeAttribute("value",valueString,replaceExisting: true);
        builder.MergeAttribute("name",name,replaceExisting: true);

        var modelState = ModelState[name];
        string modelValue = null;
        if (modelState != null) {
            modelValue = ConvertTo(modelState.Value,typeof(string)) as string;
            isChecked = isChecked ?? String.Equals(modelValue,StringComparison.OrdinalIgnoreCase);
        }

        if (isChecked.HasValue) {
            // Overrides attribute values
            if (isChecked.Value) {
                builder.MergeAttribute("checked","checked",true);
            }
            else {
                builder.Attributes.Remove("checked");
            }
        }

        AddErrorClass(builder,name);

        return builder.ToHtmlString(TagRenderMode.SelfClosing);
    }