[ASP.NET MVC]为HtmlHelper添加一个RadioButtonList扩展方法

发布时间：2020-12-16 09:09:32 所属栏目：asp.Net 来源：网络整理

导读：在前面一篇文章中，我们通过对HtmlHelper的扩展简化了对DropDownList（Single-Line-Select）和ListBox（Multiple-Line-Select）的绑定，以及对作为数据源的列表进行单独维护。现在我们为HtmlHelper/HtmlHelperModel添加一个RadioButtonList/RadioButtonListF

在前面一篇文章中，我们通过对HtmlHelper的扩展简化了对DropDownList（Single-Line-Select）和ListBox（Multiple-Line-Select）的绑定，以及对作为数据源的列表进行单独维护。现在我们为HtmlHelper/HtmlHelper<Model>添加一个RadioButtonList/RadioButtonListFor扩展方法实现一组RadioButton的绑定。[源代码从这里下载]

一、RadioButtonListFor的使用

我们先来显示一下扩展的RadioButtonListFor的方法的用法。如下所示的是作为Model的Person类型，其Gender（Male/Female）、MaritalStatus（Single/Married）和Country的选项列表通过独立的组件CodeManager进行单独维护。

   1: public class Person

   3:     string Name { get; set; }

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

   7:     string Country { get; set; }

       2: @model Person


       4:     ViewBag.Title = "Index";


       6: @using (Html.BeginForm())


       8:     <table id="container">


      10:             td class="label">@Html.LabelFor(m => m.Name):</td  11:             >@Html.EditorFor(m => m.Name)  12:           13:            14:             > m.Gender):  15:             >@Html.RadioButtonListFor(m => m.Gender,"Gender")  16:           17:            18:             > m.MaritalStatus):  19:             > m.MaritalStatus,"MaritalStatus")  20:           21:            22:             > m.Country):  23:             > m.Country,"Country",RepeatDirection.Vertical)  24:         > 


      28:     table>    


    class CodeDescription


    string Description { get; set; }


       6:? 


       8:     {


      10:         this.Description = description;


      12:     }


      14: static class CodeManager


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


      18:         new CodeDescription("M",1)">"Male",1)">"Gender"),


    "S",1)">"Single",1)">"MaritalStatus"),1)" id="lnum21">  21:         "Married",1)" id="lnum22">  22:         "CN",1)">"China",1)">"Country"),1)" id="lnum23">  23:         "US",1)">"Unite States",1)">"UK",1)">"Britain",1)">"SG",1)">"Singapore",1)">"Country")


      27:     static Collection<CodeDescription> GetCodes(  28:     {


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


      32:             codeCollection.Add(code);


      34:         return codeCollection;


      36: }

三、RadioButtonList/RadioButtonListFor扩展方法

如下所示的是RadioButtonList/RadioButtonListFor两个扩展方法的定义，参数codeCategory表示作为数据源的列表类别，而RepeatDirection 枚举类型则代表同组的RadioButton的排列方向，默认为水平。从上面的例子我们可以看到，我们通过这个参数将名称为Country的RadioButtonList进行了纵向排列。通过Html生成代码我们可以看出，我们采用了Table作为布局方式，实际上ASP.NET的RadioButtonList也是这么做的。

static MvcHtmlString RadioButtonList(this HtmlHelper htmlHelper,1)">string name,1)">string codeCategory,RepeatDirection repeatDirection = RepeatDirection.Horizontal,IDictionary<string,1)">object> htmlAttributes = null)

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

   7:     }

   9:     {

11:

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

  15:         foreach (var item in attributes)

  17:             htmlAttributes.Add(item);

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

return GenerateHtml(fullHtmlFieldName,stateValue);

  23:     static MvcHtmlString GenerateHtml(object> htmlAttributes,1)">string stateValue =   24:     {

  26:         int i = 0;

  28:         {

  30:             foreach (var code in codes)

  32:                 i++;

  34:                 TagBuilder td = "td");

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

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

  40:         else

  42:               43:             {

  45:                 i++;

  47:                 TagBuilder td = "td");

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

  51:             }

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

  55:?

  57:     {

  59:?

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

  63:?

  65:         input.GenerateId(id);

  67:         input.MergeAttribute("type",1)">"radio");

  69:         input.MergeAttributes(htmlAttributes);

  71:         {

  73:         }

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

  77:     }