有没有人为ASP.NET MVC实现RadioButtonListFor <t>？</t>

Question

ASP.NET MVC Futures中有一个Html.RadioButtonList扩展方法。有没有人找到强类型版本RadioButtonListFor<T>的代码。在视图中看起来像这样：

<%= Html.RadioButtonListFor(model=>model.Item,Model.ItemList) %>

Answer 1

以下是aspx页面中的用法

    <%= Html.RadioButtonListFor(m => m.GenderRadioButtonList)%>

这是视图模型

public class HomePageViewModel
{
    public enum GenderType
    {
        Male,
        Female
    }
    public RadioButtonListViewModel<GenderType> GenderRadioButtonList { get; set; }

    public HomePageViewModel()
    {
        GenderRadioButtonList = new RadioButtonListViewModel<GenderType>
        {
            Id = "Gender",
            SelectedValue = GenderType.Male,
            ListItems = new List<RadioButtonListItem<GenderType>>
            {
                new RadioButtonListItem<GenderType>{Text = "Male", Value = GenderType.Male},
                new RadioButtonListItem<GenderType>{Text = "Female", Value = GenderType.Female}
            }
        };
    }
}

这是用于单选按钮列表的视图模型

public class RadioButtonListViewModel<T>
{
    public string Id { get; set; }
    private T selectedValue;
    public T SelectedValue
    {
        get { return selectedValue; }
        set
        {
            selectedValue = value;
            UpdatedSelectedItems();
        }
    }

    private void UpdatedSelectedItems()
    {
        if (ListItems == null)
            return;

        ListItems.ForEach(li => li.Selected = Equals(li.Value, SelectedValue));
    }

    private List<RadioButtonListItem<T>> listItems;
    public List<RadioButtonListItem<T>> ListItems
    {
        get { return listItems; }
        set
        {
            listItems = value;
            UpdatedSelectedItems();
        }
    }
}

public class RadioButtonListItem<T>
{
    public bool Selected { get; set; }

    public string Text { get; set; }

    public T Value { get; set; }

    public override string ToString()
    {
        return Value.ToString();
    }
}

这是RadioButtonListFor

的扩展方法

public static class HtmlHelperExtensions
{
    public static string RadioButtonListFor<TModel, TRadioButtonListValue>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, RadioButtonListViewModel<TRadioButtonListValue>>> expression) where TModel : class
    {
        return htmlHelper.RadioButtonListFor(expression, null);
    }

    public static string RadioButtonListFor<TModel, TRadioButtonListValue>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, RadioButtonListViewModel<TRadioButtonListValue>>> expression, object htmlAttributes) where TModel : class
    {
        return htmlHelper.RadioButtonListFor(expression, new RouteValueDictionary(htmlAttributes));
    }

    public static string RadioButtonListFor<TModel, TRadioButtonListValue>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, RadioButtonListViewModel<TRadioButtonListValue>>> expression, IDictionary<string, object> htmlAttributes) where TModel : class
    {
        var inputName = GetInputName(expression);

        RadioButtonListViewModel<TRadioButtonListValue> radioButtonList = GetValue(htmlHelper, expression);

        if (radioButtonList == null)
            return String.Empty;

        if (radioButtonList.ListItems == null)
            return String.Empty;

        var divTag = new TagBuilder("div");
        divTag.MergeAttribute("id", inputName);
        divTag.MergeAttribute("class", "radio");
        foreach (var item in radioButtonList.ListItems)
        {
            var radioButtonTag = RadioButton(htmlHelper, inputName, new SelectListItem{Text=item.Text, Selected = item.Selected, Value = item.Value.ToString()}, htmlAttributes);

            divTag.InnerHtml += radioButtonTag;
        }

        return divTag + htmlHelper.ValidationMessage(inputName, "*");
    }

    public static string GetInputName<TModel, TProperty>(Expression<Func<TModel, TProperty>> expression)
    {
        if (expression.Body.NodeType == ExpressionType.Call)
        {
            var methodCallExpression = (MethodCallExpression)expression.Body;
            string name = GetInputName(methodCallExpression);
            return name.Substring(expression.Parameters[0].Name.Length + 1);

        }
        return expression.Body.ToString().Substring(expression.Parameters[0].Name.Length + 1);
    }

    private static string GetInputName(MethodCallExpression expression)
    {
        // p => p.Foo.Bar().Baz.ToString() => p.Foo OR throw...

        var methodCallExpression = expression.Object as MethodCallExpression;
        if (methodCallExpression != null)
        {
            return GetInputName(methodCallExpression);
        }
        return expression.Object.ToString();
    }

    public static string RadioButton(this HtmlHelper htmlHelper, string name, SelectListItem listItem,
                         IDictionary<string, object> htmlAttributes)
    {
        var inputIdSb = new StringBuilder();
        inputIdSb.Append(name)
            .Append("_")
            .Append(listItem.Value);

        var sb = new StringBuilder();

        var builder = new TagBuilder("input");
        if (listItem.Selected) builder.MergeAttribute("checked", "checked");
        builder.MergeAttribute("type", "radio");
        builder.MergeAttribute("value", listItem.Value);
        builder.MergeAttribute("id", inputIdSb.ToString());
        builder.MergeAttribute("name", name + ".SelectedValue");
        builder.MergeAttributes(htmlAttributes);
        sb.Append(builder.ToString(TagRenderMode.SelfClosing));
        sb.Append(RadioButtonLabel(inputIdSb.ToString(), listItem.Text, htmlAttributes));
        sb.Append("<br>");

        return sb.ToString();
    }

    public static string RadioButtonLabel(string inputId, string displayText,
                                 IDictionary<string, object> htmlAttributes)
    {
        var labelBuilder = new TagBuilder("label");
        labelBuilder.MergeAttribute("for", inputId);
        labelBuilder.MergeAttributes(htmlAttributes);
        labelBuilder.InnerHtml = displayText;

        return labelBuilder.ToString(TagRenderMode.Normal);
    }


    public static TProperty GetValue<TModel, TProperty>(HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression) where TModel : class
    {
        TModel model = htmlHelper.ViewData.Model;
        if (model == null)
        {
            return default(TProperty);
        }
        Func<TModel, TProperty> func = expression.Compile();
        return func(model);
    }
}

Answer 2

MVC 3示例，它创建了3个带有验证的单选按钮，以确保选择1个选项。如果表单未通过验证（例如，在其他字段上），则在重新表示表单时会预先选择所选的无线电选项。

查看

@Html.RadioButtonForSelectList(m => m.TestRadio, Model.TestRadioList)
@Html.ValidationMessageFor(m => m.TestRadio)

<强>模型

public class aTest
{
    public Int32 ID { get; set; }
    public String Name { get; set; }
}

public class LogOnModel
{
    public IEnumerable<SelectListItem> TestRadioList { get; set; }

    [Required(ErrorMessage="Test Error")]
    public String TestRadio { get; set; }

    [Required]
    [Display(Name = "User name")]
    public string UserName { get; set; }
}

控制器操作

public ActionResult LogOn()
    {
        List<aTest> list = new List<aTest>();
        list.Add(new aTest() { ID = 1, Name = "Line1" });
        list.Add(new aTest() { ID = 2, Name = "Line2" });
        list.Add(new aTest() { ID = 3, Name = "Line3" });

        SelectList sl = new SelectList(list, "ID", "Name");

        var model = new LogOnModel();
        model.TestRadioList = sl;

        return View(model);
    }

    [HttpPost]
    public ActionResult LogOn(LogOnModel model, string returnUrl)
    {
        if (ModelState.IsValid)
        {
             ....
        }

        // If we got this far, something failed, redisplay form
        List<aTest> list = new List<aTest>();
        list.Add(new aTest() { ID = 1, Name = "Line1" });
        list.Add(new aTest() { ID = 2, Name = "Line2" });
        list.Add(new aTest() { ID = 3, Name = "Line3" });

        SelectList sl = new SelectList(list, "ID", "Name");
        model.TestRadioList = sl;

        return View(model);
    }

以下是扩展程序：

public static class HtmlExtensions
{
    public static MvcHtmlString RadioButtonForSelectList<TModel, TProperty>(
        this HtmlHelper<TModel> htmlHelper,
        Expression<Func<TModel, TProperty>> expression,
        IEnumerable<SelectListItem> listOfValues)
    {
        var metaData = ModelMetadata.FromLambdaExpression(expression, htmlHelper.ViewData);
        var sb = new StringBuilder();

        if (listOfValues != null)
        {
            foreach (SelectListItem item in listOfValues)
            {
                var id = string.Format(
                    "{0}_{1}",
                    metaData.PropertyName,
                    item.Value
                );

                var radio = htmlHelper.RadioButtonFor(expression, item.Value, new { id = id }).ToHtmlString();
                sb.AppendFormat(
                    "<label for=\"{0}\">{1}</label> {2}",
                    id,
                    HttpUtility.HtmlEncode(item.Text),
                    radio
                );
            }
        }

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

Answer 3

好的，我知道这不是你问题的直接答案，但这可能是一个更好的方式来做大多数输入（并且它很有趣）。我刚刚完成了这项工作并对其进行了少量测试，所以我无法保证在任何情况下这都是完美的。

我从Jimmy Bogard的帖子here得到了这个想法。看一看，因为那里有很多很酷的想法。

我所做的是创建一个“InputFor”帮助器，它会尽力确定您要求的输入并相应地输出它。这将执行单选按钮，但如果有两个以上，则默认为下拉，您应该可以非常轻松地更改此功能。

以下代码允许您拨打<%= Html.InputFor(m => m.Gender) %>或<%Html.InputFor(m => m.Gender, Model.GenderList)%>等电话。最后有一点很酷，允许你按照惯例进行编码，但我们稍后会讨论。

public static MvcHtmlString InputFor<TModel>(this HtmlHelper<TModel> helper, Expression<Func<TModel, object>> field, Dictionary<string, string> listing) where TModel : class
        {
            string property_name = GetInputName(field);
            PropertyDescriptor descriptor = TypeDescriptor.GetProperties(helper.ViewData.Model).Find(property_name, true);
            string property_type = descriptor.PropertyType.Name;
            var func = field.Compile();
            var value = func(helper.ViewData.Model);

            //Add hidden element if required
            if (descriptor.Attributes.Contains(new HiddenInputAttribute()))
            {
                return helper.Hidden(property_name, value);
            }

            if (property_type == "DateTime" || property_type == "Date")
            {
                return helper.TextBox(property_name, value, new { @class = "date_picker" });
            }
            if (listing != null)
            {
                if (listing.Count <= 2)
                {
                    //This is a good length for a radio button
                    string output = "";
                    foreach (KeyValuePair<string, string> pair in listing)
                    {
                        TagBuilder label = new TagBuilder("label");
                        label.MergeAttribute("for", property_name);
                        label.SetInnerText(pair.Value);
                        output += helper.RadioButton(property_name, pair.Key, (value == pair.Key)).ToHtmlString();
                        output += label.ToString();
                    }
                    return MvcHtmlString.Create(output);
                }
                else
                {
                    //too big for a radio button, lets make a drop down
                    return helper.DropDownList(property_name, new SelectList(listing, "Key", "Value"), value);
                }
            }
            else
            {
                if (property_type == "Boolean")
                {
                    listing = new Dictionary<string, string>();
                    listing.Add("true", "Yes");
                    listing.Add("false", "No");
                    SelectList select_values = new SelectList(listing, "Key", "Value", ((bool)value ? "Yes" : "No"));
                    return helper.DropDownList(property_name, select_values);
                }
                return helper.TextBox(property_name, value);
            }
        }

按惯例编码

以下代码允许使用约定优于配置来完成此操作。例如，如果您有一个模型对象，其中包含您要列出的属性（性别）和一个具有相同名称但附加了“List”（GenderList）的字典，那么默认情况下它将使用此列表。

e.g。 <%= Html.InputFor(m => m.Gender) %>可以制作完整的下拉列表/单选按钮组，但可以通过拨打<%= Html.InputFor(m => m.Gender, alternate_list) %>

之类的电话来覆盖这些默认值

public static MvcHtmlString InputFor<TModel>(this HtmlHelper<TModel> helper, Expression<Func<TModel, object>> field) where TModel : class
{
    string property_name = GetInputName(field) + "List";
    PropertyDescriptor list_descriptor = TypeDescriptor.GetProperties(helper.ViewData.Model).Find(property_name, true);
    Dictionary<string, string> listing = null;

    if (list_descriptor != null)
    {
        //Found a match for PropertyNameList, try to pull it out so we can use it
        PropertyInfo temp = helper.ViewData.Model.GetType().GetProperty(property_name);
        listing = (Dictionary<string, string>)temp.GetValue(helper.ViewData.Model, null);
    }
    return InputFor(helper, field, listing);
}

现在轻微的免责声明：

• 这不是世界上最快的代码（由于反射和其他事情），在我的情况下这并不是真正相关的，因为它是所有用户驱动的，如果你打算做一些疯狂的事情。 / LI>
• 此代码尚处于起步阶段，我将对此进行更彻底的测试，并在接下来的几天内对其进行补充，并接受任何改进代码的建议。

我希望这段代码对某人有用，我知道我会在接下来的几周内使用它来尝试减少时间。把它缩小到只做单选按钮应该是一项微不足道的任务，祝你好运：）

杰

Answer 4

基于Jon post，使用HTMLAttributtes生成单选按钮列表的小改进

public static MvcHtmlString RadioButtonListFor<TModel, TProperty>(
        this HtmlHelper<TModel> htmlHelper,
        Expression<Func<TModel, TProperty>> expression,
        IEnumerable<SelectListItem> listOfValues,
        IDictionary<string, object> radioHtmlAttributes = null,
        string ulClass = null)
    {
        ModelMetadata metaData = ModelMetadata.FromLambdaExpression(expression, htmlHelper.ViewData);

        if (radioHtmlAttributes == null)
            radioHtmlAttributes = new RouteValueDictionary();

        TagBuilder ulTag = new TagBuilder("ul");
        if (!String.IsNullOrEmpty(ulClass))
            ulTag.MergeAttribute("class", ulClass);

        if (listOfValues != null)
        {
            // Create a radio button for each item in the list 
            foreach (SelectListItem item in listOfValues)
            {

                // Generate an id to be given to the radio button field 
                var id = string.Format("{0}_{1}", metaData.PropertyName, item.Value);

                if (!radioHtmlAttributes.ContainsKey("id"))
                    radioHtmlAttributes.Add("id", id);
                else
                    radioHtmlAttributes["id"] = id;

                // Create and populate a radio button using the existing html helpers 
                var label = htmlHelper.Label(id, HttpUtility.HtmlEncode(item.Text));
                var radio = htmlHelper.RadioButtonFor(expression, item.Value, radioHtmlAttributes).ToHtmlString();

                // Create the html string that will be returned to the client 
                // e.g. <input data-val="true" data-val-required="You must select an option" id="TestRadio_1" name="TestRadio" type="radio" value="1" /><label for="TestRadio_1">Line1</label> 
                ulTag.InnerHtml += string.Format("<li>{0}{1}</li>", radio, label);
            }
        }

        return MvcHtmlString.Create(ulTag.ToString(TagRenderMode.Normal));
    }

    public static MvcHtmlString RadioButtonListFor<TModel, TProperty>(
        this HtmlHelper<TModel> htmlHelper,
        Expression<Func<TModel, TProperty>> expression,
        IEnumerable<SelectListItem> listOfValues,
        object radioHtmlAttributes = null,
        string ulClass = null)
    {
        return RadioButtonListFor<TModel, TProperty>(htmlHelper, expression, listOfValues, new RouteValueDictionary(radioHtmlAttributes), ulClass);
    }

Answer 5

我在MVC 1.0中实现了类似的功能。看看这对你有用：

    public static string RadioButtonList2(this HtmlHelper _helper, string _name, IEnumerable<SelectListItem> _items, string _selectedValue, string _seperator)
    {
        return RadioButtonList2(_helper, _name, _items, _selectedValue, _seperator, null);
    }

    public static string RadioButtonList2(this HtmlHelper _helper, string _name, IEnumerable<SelectListItem> _items, string _selectedValue, string _seperator, IDictionary<string, object> _htmlAttributes)
    {
        StringBuilder _outputScript = new StringBuilder();

        foreach (var item in _items)
        {
            var optionField = new TagBuilder("input");
            optionField.MergeAttribute("name", _name);
            optionField.MergeAttribute("id", _name);
            optionField.MergeAttribute("class", _name);
            optionField.MergeAttribute("value", item.Value);
            optionField.MergeAttribute("type", "radio");

            // Check to see if it's checked
            if (item.Value == _selectedValue)
                optionField.MergeAttribute("checked", "checked");

            if (_htmlAttributes != null)
                optionField.MergeAttributes(_htmlAttributes);

            _outputScript.Append(optionField.ToString(TagRenderMode.SelfClosing));
            _outputScript.Append("<label style=\"display:inline;\">");
            _outputScript.Append(item.Text);
            _outputScript.Append("</label>" + _seperator);
        }

        return _outputScript.ToString();
    }

在控制器中，您可以按如下方式返回结果：

        ViewData["GenderList"] = new SelectList(new[] { new { Value = "M", Text = "Male" }, new { Value = "F", Text = "Female" }, new { Value = "A", Text = "All" } }, "Value", "Text");

或

        ViewData["GenderList"] = new SelectList(_resultFromSomeLinqQuery, "GenderID", "GenderName");

在View中使用它如下：

<%= Html.RadioButtonList2("Sex", ViewData["GenderList"] as SelectList, ViewData["SelectedSex"].ToString(), "&nbsp;")%>

您也可以将 替换为<BR />，以单独的行显示它们。

希望这有帮助。

此致 Naweed Akram naweed@xgeno.com

Answer 6

这是一个稍微“瘦”的答案，好的'VB'。 适合我，但它不是一个完整的解决方案。

<Extension()> _
Public Function RadioButtonListFor(Of TModel, TProperty)(ByVal htmlHelper As System.Web.Mvc.HtmlHelper(Of TModel), ByVal expression As System.Linq.Expressions.Expression(Of System.Func(Of TModel, TProperty)), ByVal selectList As System.Collections.Generic.IEnumerable(Of System.Web.Mvc.SelectListItem), ByVal htmlAttributes As Object) As System.Web.Mvc.MvcHtmlString
    'Return htmlHelper.DropDownListFor(expression, selectList, htmlAttributes)
    If selectList Is Nothing OrElse selectList.Count = 0 Then Return MvcHtmlString.Empty

    Dim divTag = New TagBuilder("div")
    divTag.MergeAttributes(New RouteValueDictionary(htmlAttributes))
    Dim name = CType(expression.Body, System.Linq.Expressions.MemberExpression).Member.Name
    Dim value = expression.Compile()(htmlHelper.ViewData.Model)
    Dim sb As New StringBuilder()

    For Each item In selectList
        sb.AppendFormat("<input id=""{0}_{1}"" type=""radio"" name=""{0}"" value=""{1}"" {2} />", name, item.Value, If(item.Value = value.ToString, """checked""", ""))
        sb.AppendFormat("<label for=""{0}_{1}"">{2}</label>", name, item.Value, item.Text)
    Next

    divTag.InnerHtml = sb.ToString

    Return MvcHtmlString.Create(divTag.ToString)

End Function

Answer 7

我修改了Mac的解决方案并用数据库表替换了枚举类型，我的表是：

在我的申请表中，我根据性别偏好租用房间。 我使用GenderRadios属性的模型：

public partial class Room
{
 public RadioButtonListViewModel GenderRadios { get; set; }
 //...
}

在室内控制器中，我正在准备无线电：

   private void fillRadios(Room room)
    {         
        List<Gender> genders = fre.Genders.ToList();
        room.GenderRadios= new RadioButtonListViewModel();
        room.GenderRadios.ListItems = new List<RadioButtonListItem>();
        foreach (Gender gender in genders)
            room.GenderRadios.ListItems.Add(new RadioButtonListItem { Text = gender.Name, Value = gender.Id, Selected= (room.GenderId == gender.Id)});
    }

最后，我在视图中使用它来创建空间：

<tr> 
<td>Gender</td>
   <%= Html.RadioButtonListFor(m => m.GenderRadios, "GenderRadiosForRoomCreate")%>         
</tr>

和编辑室：

<tr> 
<td>Gender</td>
    <%= Html.RadioButtonListFor(m => m.GenderRadios, "GenderRadiosForRoomEdit")%>         
</tr>

创建房间html将如下所示：

<td id="GenderRadisoForRoomCreate_Container">
<input id="GenderRadisoForRoomCreate_Any" name="GenderRadisoForRoomCreate_value" value="1" type="radio"><label for="GenderRadisoForRoomCreate_Any">Any</label>
<input id="GenderRadisoForRoomCreate_Female" name="GenderRadisoForRoomCreate_value" value="2" type="radio"><label for="GenderRadisoForRoomCreate_Female">Female</label>
<input id="GenderRadisoForRoomCreate_Male" name="GenderRadisoForRoomCreate_value" value="3" type="radio"><label for="GenderRadisoForRoomCreate_Male">Male</label>
</td>

创建空间时：

[HttpPost]
public ActionResult RoomCreate(Room room, FormCollection formValues, int? GenderRadiosForRoomCreate_value, int? SmokingRadiosForRoomCreate_value)
{
    room.GenderId = GenderRadiosForRoomCreate_value;
    room.SmokingId = SmokingRadiosForRoomCreate_value;
//...
}

这是助手类：

public class RadioButtonListViewModel
{
    public int Id { get; set; }

    private int selectedValue;
    public int SelectedValue
    {
        get { return selectedValue; }
        set
        {
            selectedValue = value;
            UpdatedSelectedItems();
        }
    }

    private void UpdatedSelectedItems()
    {
        if (ListItems == null)
            return;

        ListItems.ForEach(li => li.Selected = Equals(li.Value, SelectedValue));
    }

    private List<RadioButtonListItem> listItems;
    public List<RadioButtonListItem> ListItems
    {
        get { return listItems; }
        set
        {
            listItems = value;
            UpdatedSelectedItems();
        }
    }
}

public class RadioButtonListItem
{
    public bool Selected { get; set; }

    public string Text { get; set; }



    public int Value { get; set; }

    public override string ToString()
    {
        return Value.ToString();
    }
}



public static class HtmlHelperExtensions
{
    /* 
     tagBase: I used tagBase string for building other tag's Id or Name on this. i.e. for tagBase="GenderRadiosForRoomCreate" 
        <td id="GenderRadisoForRoomCreate_Container">
        <input id="GenderRadisoForRoomCreate_Any" name="GenderRadisoForRoomCreate_value" value="1" type="radio"><label for="GenderRadisoForRoomCreate_Any">Any</label>
        <input id="GenderRadisoForRoomCreate_Female" name="GenderRadisoForRoomCreate_value" value="2" type="radio"><label for="GenderRadisoForRoomCreate_Female">Female</label>
        <input id="GenderRadisoForRoomCreate_Male" name="GenderRadisoForRoomCreate_value" value="3" type="radio"><label for="GenderRadisoForRoomCreate_Male">Male</label>
        </td>     
    */
    public static string RadioButtonListFor<TModel>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, RadioButtonListViewModel>> expression, String tagBase) where TModel : class
    {
        return htmlHelper.RadioButtonListFor(expression, tagBase, null);
    }

    public static string RadioButtonListFor<TModel>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, RadioButtonListViewModel>> expression, String tagBase, object htmlAttributes) where TModel : class
    {
        return htmlHelper.RadioButtonListFor(expression, tagBase, new RouteValueDictionary(htmlAttributes));
    }

    public static string RadioButtonListFor<TModel>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, RadioButtonListViewModel>> expression, String tagBase, IDictionary<string, object> htmlAttributes) where TModel : class
    {        
        var inputName = tagBase;
        RadioButtonListViewModel radioButtonList = GetValue(htmlHelper, expression);

        if (radioButtonList == null)
            return String.Empty;

        if (radioButtonList.ListItems == null)
            return String.Empty;


        var containerTag = new TagBuilder("td");
        containerTag.MergeAttribute("id", inputName + "_Container");                
        foreach (var item in radioButtonList.ListItems)
        {
            var radioButtonTag = RadioButton(htmlHelper, inputName, new SelectListItem{Text=item.Text, Selected = item.Selected, Value = item.Value.ToString()}, htmlAttributes);

            containerTag.InnerHtml += radioButtonTag;
        }

        return containerTag.ToString();
    }

    public static string RadioButton(this HtmlHelper htmlHelper, string name, SelectListItem listItem,
                         IDictionary<string, object> htmlAttributes)
    {
        var inputIdSb = new StringBuilder();
        inputIdSb.Append(name);

        var sb = new StringBuilder();

        var builder = new TagBuilder("input");
        if (listItem.Selected) builder.MergeAttribute("checked", "checked");
        builder.MergeAttribute("type", "radio");
        builder.MergeAttribute("value", listItem.Value);
        builder.MergeAttribute("id", inputIdSb.ToString() + "_" + listItem.Text);    
        builder.MergeAttribute("name", name + "_value");
        builder.MergeAttributes(htmlAttributes);
        sb.Append(builder.ToString(TagRenderMode.SelfClosing));
        sb.Append(RadioButtonLabel(inputIdSb.ToString(), listItem.Text, htmlAttributes));
        return sb.ToString();
    }

    public static string RadioButtonLabel(string inputId, string displayText,
                                 IDictionary<string, object> htmlAttributes)
    {
        var labelBuilder = new TagBuilder("label");
        labelBuilder.MergeAttribute("for", inputId + "_" + displayText);
        labelBuilder.MergeAttributes(htmlAttributes);
        labelBuilder.InnerHtml = displayText;

        return labelBuilder.ToString(TagRenderMode.Normal);
    }


    public static TProperty GetValue<TModel, TProperty>(HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression) where TModel : class
    {
        TModel model = htmlHelper.ViewData.Model;
        if (model == null)
        {
            return default(TProperty);
        }
        Func<TModel, TProperty> func = expression.Compile();
        return func(model);
    }
}