asp.net Mvc3 扩展 RadioButtonFor 为 RadioButtonListFor

   Mvc 3 中 有RadioButtonFor 但是没有list，扩展一下，方法如下：

   

   

public static MvcHtmlString RadioButtonListFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, IEnumerable<SelectListItem> selectList, string optionLabel, IDictionary<string, object> htmlAttributes)
        {
            if (expression == null)
            {
                throw new ArgumentNullException("expression");
            }
            string name = ExpressionHelper.GetExpressionText(expression);

            string fullName = htmlHelper.ViewContext.ViewData.TemplateInfo.GetFullHtmlFieldName(name);
            if (String.IsNullOrEmpty(fullName))
            {
                throw new ArgumentException("name");
            }

            bool usedViewData = false;

            // If we got a null selectList, try to use ViewData to get the list of items.
            if (selectList == null)
            {
                selectList = htmlHelper.GetSelectData(fullName);
                usedViewData = true;
            }

            object defaultValue = htmlHelper.GetModelStateValue(fullName, typeof(string));

            // If we haven't already used ViewData to get the entire list of items then we need to
            // use the ViewData-supplied value before using the parameter-supplied value.
            if (!usedViewData)
            {
                if (defaultValue == null)
                {
                    defaultValue = htmlHelper.ViewData.Eval(fullName);
                }
            }
            if (defaultValue != null)
            {
                IEnumerable defaultValues =  new[] { defaultValue };
                IEnumerable<string> values = from object value in defaultValues select Convert.ToString(value, CultureInfo.CurrentCulture);
                HashSet<string> selectedValues = new HashSet<string>(values, StringComparer.OrdinalIgnoreCase);
                List<SelectListItem> newSelectList = new List<SelectListItem>();

                foreach (SelectListItem item in selectList)
                {
                    item.Selected = (item.Value != null) ? selectedValues.Contains(item.Value) : selectedValues.Contains(item.Text);
                    newSelectList.Add(item);
                }
                selectList = newSelectList;
            }


            #region  

            TagBuilder table = new TagBuilder("table");
            int i = 0;

            foreach (SelectListItem item in selectList)
            {
                //
                TagBuilder tr = new TagBuilder("tr");
                i++;
                string id = string.Format("{0}_{1}", name, i);
                TagBuilder td = new TagBuilder("td");
                td.InnerHtml = GenerateRadioHtml(name, id, item.Text, item.Value, item.Selected, htmlAttributes);
                tr.InnerHtml = td.ToString();
                table.InnerHtml += tr.ToString();
            }

            #endregion

            return new MvcHtmlString(table.ToString());
        }

  还有：

   

private static IEnumerable<SelectListItem> GetSelectData(this HtmlHelper htmlHelper, string name)
        {
            object o = null;
            if (htmlHelper.ViewData != null)
            {
                o = htmlHelper.ViewData.Eval(name);
            }
            if (o == null)
            {
                throw new InvalidOperationException(
                        "IEnumerable<SelectListItem>");
            }
            IEnumerable<SelectListItem> selectList = o as IEnumerable<SelectListItem>;
            if (selectList == null)
            {
                throw new InvalidOperationException(
                        "IEnumerable<SelectListItem>");
            }
            return selectList;
    

   

  

 private static object GetModelStateValue(this HtmlHelper htmlHelper, string key, Type destinationType)
        {
            ModelState modelState;
            if (htmlHelper.ViewData.ModelState.TryGetValue(key, out modelState))
            {
                if (modelState.Value != null)
                {
                    return modelState.Value.ConvertTo(destinationType, null /* culture */);
                }
            }
            return null;
        }

 

private static string GenerateRadioHtml(string name, string id, string labelText, string value, bool isChecked, IDictionary<string, object> htmlAttributes)
        {
            StringBuilder sb = new StringBuilder();

            TagBuilder label = new TagBuilder("label");
            label.MergeAttribute("for", id);
            label.SetInnerText(labelText);

            TagBuilder input = new TagBuilder("input");
            input.GenerateId(id);
            input.MergeAttribute("name", name);
            input.MergeAttribute("type", "radio");
            input.MergeAttribute("value", value);
            input.MergeAttributes(htmlAttributes);
            if (isChecked)
            {
                input.MergeAttribute("checked", "checked");
            }
            sb.AppendLine(input.ToString());
            sb.AppendLine(label.ToString());
            return sb.ToString();
        }

        页面使用如下：

       

@Html.RadioButtonListFor(c => c.ModelType, ((IEnumerable<ParmInfo>)ViewBag.Test).Select(m => new 
           SelectListItem { Text = m.parmName, Value = m.parmValue, Selected = (m.parmValue == "0") }), "", null)

     最终形成如下图所示：