在ASP.NET MVC中使用“RadioButtonList”和“CheckBoxList”

在《为HtmlHelper添加一个RadioButtonList扩展方法》中我通过对HtmlHelper和HtmlHelper<Model>的扩展使我们可以采用”RadioButtonList”的方式对一组类型为“radio”的<input>元素进行操作。昨天对对此进行了一些改进，并将“CheckBoxList”的功能添加进来。[源代码从这里下载]

一、有何特别之处？

和我的很多文章一样，旨在提供一种大体的解决方案，本解决方案旨在解决如下一些问题：

• 通过独立的组件对绑定到ListControl（ASP.NET Web Form的说法）的列表进行单独管理；
• 自动地调用上面这个组件获取列表信息进行相关Html的生成；
• 支持ASP.NET MVC原生的Model Binding。

二、实例演示

我们还是以《为HtmlHelper添加一个RadioButtonList扩展方法》例子来演示RadioButtonList和CheckBoxList用法。下面是代表个人信息同时作为Model的Person类型，Gender、MaritalStatus 和Country分别代表性别、婚姻状况和国籍（这里支持多国籍）。

   1: public class Person

   2: {

   3:     public string Name { get; set; }

   4:     public string Gender { get; set; }

   5:     [Display(Name = "Marital Status")]

   6:     public string MaritalStatus { get; set; }

   7:     public string[] Country { get; set; }

   8: }

上述三个属性分别代表CodeManager这个独立组件维护的三个列表，CodeManager和代表列表选项的CodeDescription定义如下：

   1: public class CodeDescription

   2: {

   3:     public string Code { get; set; }

   4:     public string Description { get; set; }

   5:     public string Category{get;set;}

   6:  

   7:     public CodeDescription(string code, string description, string category)

   8:     {

   9:         this.Code = code;

  10:         this.Description = description;

  11:         this.Category = category;

  12:     }

  13: }

  14: public static class CodeManager

  15: {

  16:     private static CodeDescription[] codes = new CodeDescription[]

  17:     {

  18:         new CodeDescription("M","Male","Gender"),

  19:         new CodeDescription("F","Female","Gender"),

  20:         new CodeDescription("S","Single","MaritalStatus"),

  21:         new CodeDescription("M","Married","MaritalStatus"),

  22:         new CodeDescription("CN","China","Country"),

  23:         new CodeDescription("US","Unite States","Country"),

  24:         new CodeDescription("UK","Britain","Country"),

  25:         new CodeDescription("SG","Singapore","Country")

  26:     };

  27:     public static Collection<CodeDescription> GetCodes(string category)

  28:     {

  29:         Collection<CodeDescription> codeCollection = new Collection<CodeDescription>();

  30:         foreach(var code in codes.Where(code=>code.Category == category))

  31:         {

  32:             codeCollection.Add(code);

  33:         }

  34:         return codeCollection;

  35:     }

  36: }

在默认的HomeController中，我们定义了如下两个Index方法，它们分别用于测试出栈数据（Model->UI)入栈数据（UI-〉Model）的绑定。

   1: public class HomeController : Controller

   2: {

   3:     public ActionResult Index()

   4:     {

   5:         return View(new Person { Name = "Foo", Gender = "M", MaritalStatus = "S", Country = new string[]{"CN","US"} });

   6:     }

   7:     [HttpPost]

   8:     public ActionResult Index(Person person)

   9:     {

  10:         return this.View(person);

  11:     }

  12: }

下面是Index操作对应的View的定义，这是一个Model类型为Person的强类型View。对于Person的三个基于列表的属性，我们分别调用了自定义的扩展方法RadioButtonListFor和CheckBoxListFor进行了绑定。方法的最后两个参数分别代表通过CodeManager维护的列表的组别（Gender、MaritalStatus和Country），和同组RadioButton和CheckBox布局方向（水平或者纵向）。

   1: @using System.Web.UI.WebControls

   2: @model Person

   3: @{

   4:     ViewBag.Title = "Index";

   5: }

   6: @using (Html.BeginForm())

   7: { 

   8:     <table id="container">

   9:         <tr>

  10:             <td class="label">@Html.LabelFor(m => m.Name):</td>

  11:             <td>@Html.EditorFor(m => m.Name)</td>

  12:         </tr>

  13:          <tr>

  14:             <td class="label">@Html.LabelFor(m => m.Gender):</td>

  15:             <td>@Html.RadioButtonListFor(m => m.Gender, "Gender")</td>

  16:         </tr>

  17:          <tr>

  18:             <td class="label">@Html.LabelFor(m => m.MaritalStatus):</td>

  19:             <td>@Html.RadioButtonListFor(m => m.MaritalStatus, "MaritalStatus")</td>

  20:         </tr>

  21:          <tr>

  22:             <td class="label">@Html.LabelFor(m => m.Country):</td>

  23:             <td>@Html.CheckBoxListFor(m => m.Country, "Country", RepeatDirection.Vertical)</td>

  24:         </tr> 

  25:         <tr>

  26:             <td colspan="2"><input type="submit" value="Save" /></td>

  27:         </tr>      

  28:     </table>    

  29: }

下面是最终呈现出来的效果：

三、两组扩展方法具体实现

现在我们简单地来看看RadioButtonList/RadioButtonListFor和CheckBoxList/CheckBoxListFor这两组扩展方法的实现。我们通过CodeManager得到列表集合，通过HtmlHelper结合 ModelMetadata得到当前数据，最终借助于ListControlUtil的GenerateHtml生成相关的Html。

   1: public static class ListControlExtensions

   2: {

   3:     public static MvcHtmlString RadioButtonList(this HtmlHelper htmlHelper, string name, string codeCategory, RepeatDirection repeatDirection = RepeatDirection.Horizontal)

   4:     {

   5:         var codes = CodeManager.GetCodes(codeCategory);

   6:         return ListControlUtil.GenerateHtml(name, codes, repeatDirection,"radio",null);

   7:     }

   8:     public static MvcHtmlString RadioButtonListFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, string codeCategory, RepeatDirection repeatDirection = RepeatDirection.Horizontal)

   9:     {

  10:         var codes = CodeManager.GetCodes(codeCategory);

  11:         ModelMetadata metadata = ModelMetadata.FromLambdaExpression<TModel, TProperty>(expression, htmlHelper.ViewData);

  12:         string name = ExpressionHelper.GetExpressionText(expression);           

  13:         string fullHtmlFieldName = htmlHelper.ViewContext.ViewData.TemplateInfo.GetFullHtmlFieldName(name);

  14:         return ListControlUtil.GenerateHtml(fullHtmlFieldName, codes, repeatDirection, "radio", metadata.Model);

  15:     }

  16:  

  17:     public static MvcHtmlString CheckBoxList(this HtmlHelper htmlHelper, string name, string codeCategory, RepeatDirection repeatDirection = RepeatDirection.Horizontal)

  18:     {

  19:         var codes = CodeManager.GetCodes(codeCategory);

  20:         return ListControlUtil.GenerateHtml(name, codes, repeatDirection, "checkbox", null);

  21:     }

  22:     public static MvcHtmlString CheckBoxListFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, string codeCategory, RepeatDirection repeatDirection = RepeatDirection.Horizontal)

  23:     {

  24:         var codes = CodeManager.GetCodes(codeCategory);

  25:         ModelMetadata metadata = ModelMetadata.FromLambdaExpression<TModel, TProperty>(expression, htmlHelper.ViewData);

  26:         string name = ExpressionHelper.GetExpressionText(expression);

  27:         string fullHtmlFieldName = htmlHelper.ViewContext.ViewData.TemplateInfo.GetFullHtmlFieldName(name);

  28:         return ListControlUtil.GenerateHtml(fullHtmlFieldName, codes, repeatDirection, "checkbox", metadata.Model);

  29:     }

  30: }

ListControlUtil中生成相关Html的逻辑定义如下：

   1: public static class ListControlUtil

   2: {

   3:     public static MvcHtmlString GenerateHtml(string name, Collection<CodeDescription> codes, RepeatDirection repeatDirection, string type, object stateValue)

   4:     {

   5:         TagBuilder table = new TagBuilder("table");

   6:         int i = 0;

   7:         bool isCheckBox = type == "checkbox";

   8:         if (repeatDirection == RepeatDirection.Horizontal)

   9:         {

  10:             TagBuilder tr = new TagBuilder("tr");

  11:             foreach (var code in codes)

  12:             {

  13:                 i++;

  14:                 string id = string.Format("{0}_{1}", name, i);

  15:                 TagBuilder td = new TagBuilder("td");

  16:  

  17:                 bool isChecked = false;

  18:                 if (isCheckBox)

  19:                 {

  20:                     IEnumerable<string> currentValues = stateValue as IEnumerable<string>;

  21:                     isChecked = (null != currentValues && currentValues.Contains(code.Code));

  22:                 }

  23:                 else

  24:                 {

  25:                     string currentValue = stateValue as string;

  26:                     isChecked = (null != currentValue && code.Code == currentValue);

  27:                 }

  28:  

  29:                 td.InnerHtml = GenerateRadioHtml(name, id, code.Description, code.Code, isChecked,type);

  30:                 tr.InnerHtml += td.ToString();

  31:             }

  32:             table.InnerHtml = tr.ToString();

  33:         }

  34:         else

  35:         {

  36:             foreach (var code in codes)

  37:             {

  38:                 TagBuilder tr = new TagBuilder("tr");

  39:                 i++;

  40:                 string id = string.Format("{0}_{1}", name, i);

  41:                 TagBuilder td = new TagBuilder("td");

  42:  

  43:                 bool isChecked = false;

  44:                 if (isCheckBox)

  45:                 {

  46:                     IEnumerable<string> currentValues = stateValue as IEnumerable<string>;

  47:                     isChecked = (null != currentValues && currentValues.Contains(code.Code));

  48:                 }

  49:                 else

  50:                 {

  51:                     string currentValue = stateValue as string;

  52:                     isChecked = (null != currentValue && code.Code == currentValue);

  53:                 }

  54:  

  55:                 td.InnerHtml = GenerateRadioHtml(name, id, code.Description, code.Code, isChecked, type);

  56:                 tr.InnerHtml = td.ToString();

  57:                 table.InnerHtml += tr.ToString();

  58:             }

  59:         }

  60:         return new MvcHtmlString(table.ToString());

  61:     }

  62:  

  63:     private static string GenerateRadioHtml(string name, string id, string labelText, string value, bool isChecked, string type)

  64:     {

  65:         StringBuilder sb = new StringBuilder();

  66:  

  67:         TagBuilder label = new TagBuilder("label");

  68:         label.MergeAttribute("for", id);

  69:         label.SetInnerText(labelText);

  70:  

  71:         TagBuilder input = new TagBuilder("input");

  72:         input.GenerateId(id);

  73:         input.MergeAttribute("name", name);

  74:         input.MergeAttribute("type", type);

  75:         input.MergeAttribute("value", value);

  76:         if (isChecked)

  77:         {

  78:             input.MergeAttribute("checked", "checked");

  79:         }

  80:         sb.AppendLine(input.ToString());

  81:         sb.AppendLine(label.ToString());

  82:         return sb.ToString();

  83:     }

  84: }

 

通过对HtmlHelper扩展简化“列表控件”的绑定 
为HtmlHelper添加一个RadioButtonList扩展方法 
在ASP.NET MVC中使用“RadioButtonList”和“CheckBoxList”

作者： Artech
出处： http://artech.cnblogs.com/
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