mcs/class/System.Web.Mvc2/System.Web.Mvc/Html/InputExtensions.cs

   1 /* ****************************************************************************\r
   2  *\r
   3  * Copyright (c) Microsoft Corporation. All rights reserved.\r
   4  *\r
   5  * This software is subject to the Microsoft Public License (Ms-PL). \r
   6  * A copy of the license can be found in the license.htm file included \r
   7  * in this distribution.\r
   8  *\r
   9  * You must not remove this notice, or any other, from this software.\r
  10  *\r
  11  * ***************************************************************************/\r
  12 \r
  13 namespace System.Web.Mvc.Html {\r
  14     using System;\r
  15     using System.Collections.Generic;\r
  16     using System.Data.Linq;\r
  17     using System.Diagnostics.CodeAnalysis;\r
  18     using System.Globalization;\r
  19     using System.Linq.Expressions;\r
  20     using System.Text;\r
  21     using System.Web.Mvc.Resources;\r
  22     using System.Web.Routing;\r
  23 \r
  24     public static class InputExtensions {\r
  25         // CheckBox\r
  26 \r
  27         public static MvcHtmlString CheckBox(this HtmlHelper htmlHelper, string name) {\r
  28             return CheckBox(htmlHelper, name, (object)null /* htmlAttributes */);\r
  29         }\r
  30 \r
  31         public static MvcHtmlString CheckBox(this HtmlHelper htmlHelper, string name, bool isChecked) {\r
  32             return CheckBox(htmlHelper, name, isChecked, (object)null /* htmlAttributes */);\r
  33         }\r
  34 \r
  35         public static MvcHtmlString CheckBox(this HtmlHelper htmlHelper, string name, bool isChecked, object htmlAttributes) {\r
  36             return CheckBox(htmlHelper, name, isChecked, new RouteValueDictionary(htmlAttributes));\r
  37         }\r
  38 \r
  39         public static MvcHtmlString CheckBox(this HtmlHelper htmlHelper, string name, object htmlAttributes) {\r
  40             return CheckBox(htmlHelper, name, new RouteValueDictionary(htmlAttributes));\r
  41         }\r
  42 \r
  43         public static MvcHtmlString CheckBox(this HtmlHelper htmlHelper, string name, IDictionary<string, object> htmlAttributes) {\r
  44             return CheckBoxHelper(htmlHelper, name, null /* isChecked */, htmlAttributes);\r
  45         }\r
  46 \r
  47         public static MvcHtmlString CheckBox(this HtmlHelper htmlHelper, string name, bool isChecked, IDictionary<string, object> htmlAttributes) {\r
  48             return CheckBoxHelper(htmlHelper, name, isChecked, htmlAttributes);\r
  49         }\r
  50 \r
  51         [SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures", Justification = "This is an appropriate nesting of generic types")]\r
  52         public static MvcHtmlString CheckBoxFor<TModel>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, bool>> expression) {\r
  53             return CheckBoxFor(htmlHelper, expression, null /* htmlAttributes */);\r
  54         }\r
  55 \r
  56         [SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures", Justification = "This is an appropriate nesting of generic types")]\r
  57         public static MvcHtmlString CheckBoxFor<TModel>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, bool>> expression, object htmlAttributes) {\r
  58             return CheckBoxFor(htmlHelper, expression, new RouteValueDictionary(htmlAttributes));\r
  59         }\r
  60 \r
  61         [SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures", Justification = "This is an appropriate nesting of generic types")]\r
  62         public static MvcHtmlString CheckBoxFor<TModel>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, bool>> expression, IDictionary<string, object> htmlAttributes) {\r
  63             if (expression == null) {\r
  64                 throw new ArgumentNullException("expression");\r
  65             }\r
  66 \r
  67             ModelMetadata metadata = ModelMetadata.FromLambdaExpression(expression, htmlHelper.ViewData);\r
  68             bool? isChecked = null;\r
  69             if (metadata.Model != null) {\r
  70                 bool modelChecked;\r
  71                 if (Boolean.TryParse(metadata.Model.ToString(), out modelChecked)) {\r
  72                     isChecked = modelChecked;\r
  73                 }\r
  74             }\r
  75 \r
  76             return CheckBoxHelper(htmlHelper, ExpressionHelper.GetExpressionText(expression), isChecked, htmlAttributes);\r
  77         }\r
  78 \r
  79         private static MvcHtmlString CheckBoxHelper(HtmlHelper htmlHelper, string name, bool? isChecked, IDictionary<string, object> htmlAttributes) {\r
  80             RouteValueDictionary attributes =\r
  81                 htmlAttributes == null ? new RouteValueDictionary()\r
  82                                        : new RouteValueDictionary(htmlAttributes);\r
  83 \r
  84             bool explicitValue = isChecked.HasValue;\r
  85             if (explicitValue) {\r
  86                 attributes.Remove("checked");    // Explicit value must override dictionary\r
  87             }\r
  88 \r
  89             return InputHelper(htmlHelper, InputType.CheckBox, name, "true", !explicitValue /* useViewData */, isChecked ?? false, true /* setId */, false /* isExplicitValue */, attributes);\r
  90         }\r
  91 \r
  92         // Hidden\r
  93 \r
  94         public static MvcHtmlString Hidden(this HtmlHelper htmlHelper, string name) {\r
  95             return Hidden(htmlHelper, name, null /* value */, null /* htmlAttributes */);\r
  96         }\r
  97 \r
  98         public static MvcHtmlString Hidden(this HtmlHelper htmlHelper, string name, object value) {\r
  99             return Hidden(htmlHelper, name, value, null /* hmtlAttributes */);\r
 100         }\r
 101 \r
 102         public static MvcHtmlString Hidden(this HtmlHelper htmlHelper, string name, object value, object htmlAttributes) {\r
 103             return Hidden(htmlHelper, name, value, new RouteValueDictionary(htmlAttributes));\r
 104         }\r
 105 \r
 106         public static MvcHtmlString Hidden(this HtmlHelper htmlHelper, string name, object value, IDictionary<string, object> htmlAttributes) {\r
 107             return HiddenHelper(htmlHelper,\r
 108                                 value,\r
 109                                 value == null /* useViewData */,\r
 110                                 name,\r
 111                                 htmlAttributes);\r
 112         }\r
 113 \r
 114         [SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures", Justification = "This is an appropriate nesting of generic types")]\r
 115         public static MvcHtmlString HiddenFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression) {\r
 116             return HiddenFor(htmlHelper, expression, (IDictionary<string, object>)null);\r
 117         }\r
 118 \r
 119         [SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures", Justification = "This is an appropriate nesting of generic types")]\r
 120         public static MvcHtmlString HiddenFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, object htmlAttributes) {\r
 121             return HiddenFor(htmlHelper, expression, new RouteValueDictionary(htmlAttributes));\r
 122         }\r
 123 \r
 124         [SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures", Justification = "This is an appropriate nesting of generic types")]\r
 125         public static MvcHtmlString HiddenFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, IDictionary<string, object> htmlAttributes) {\r
 126             return HiddenHelper(htmlHelper,\r
 127                                 ModelMetadata.FromLambdaExpression(expression, htmlHelper.ViewData).Model,\r
 128                                 false,\r
 129                                 ExpressionHelper.GetExpressionText(expression),\r
 130                                 htmlAttributes);\r
 131         }\r
 132 \r
 133         private static MvcHtmlString HiddenHelper(HtmlHelper htmlHelper, object value, bool useViewData, string expression, IDictionary<string, object> htmlAttributes) {\r
 134             Binary binaryValue = value as Binary;\r
 135             if (binaryValue != null) {\r
 136                 value = binaryValue.ToArray();\r
 137             }\r
 138 \r
 139             byte[] byteArrayValue = value as byte[];\r
 140             if (byteArrayValue != null) {\r
 141                 value = Convert.ToBase64String(byteArrayValue);\r
 142             }\r
 143 \r
 144             return InputHelper(htmlHelper, InputType.Hidden, expression, value, useViewData, false /* isChecked */, true /* setId */, true /* isExplicitValue */, htmlAttributes);\r
 145         }\r
 146 \r
 147         // Password\r
 148 \r
 149         public static MvcHtmlString Password(this HtmlHelper htmlHelper, string name) {\r
 150             return Password(htmlHelper, name, null /* value */);\r
 151         }\r
 152 \r
 153         public static MvcHtmlString Password(this HtmlHelper htmlHelper, string name, object value) {\r
 154             return Password(htmlHelper, name, value, null /* htmlAttributes */);\r
 155         }\r
 156 \r
 157         public static MvcHtmlString Password(this HtmlHelper htmlHelper, string name, object value, object htmlAttributes) {\r
 158             return Password(htmlHelper, name, value, new RouteValueDictionary(htmlAttributes));\r
 159         }\r
 160 \r
 161         public static MvcHtmlString Password(this HtmlHelper htmlHelper, string name, object value, IDictionary<string, object> htmlAttributes) {\r
 162             return PasswordHelper(htmlHelper, name, value, htmlAttributes);\r
 163         }\r
 164 \r
 165         [SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures", Justification = "This is an appropriate nesting of generic types")]\r
 166         public static MvcHtmlString PasswordFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression) {\r
 167             return PasswordFor(htmlHelper, expression, null /* htmlAttributes */);\r
 168         }\r
 169 \r
 170         [SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures", Justification = "This is an appropriate nesting of generic types")]\r
 171         public static MvcHtmlString PasswordFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, object htmlAttributes) {\r
 172             return PasswordFor(htmlHelper, expression, new RouteValueDictionary(htmlAttributes));\r
 173         }\r
 174 \r
 175         [SuppressMessage("Microsoft.Design", "CA1011:ConsiderPassingBaseTypesAsParameters", Justification = "Users cannot use anonymous methods with the LambdaExpression type")]\r
 176         [SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures", Justification = "This is an appropriate nesting of generic types")]\r
 177         public static MvcHtmlString PasswordFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, IDictionary<string, object> htmlAttributes) {\r
 178             if (expression == null) {\r
 179                 throw new ArgumentNullException("expression");\r
 180             }\r
 181 \r
 182             return PasswordHelper(htmlHelper,\r
 183                                   ExpressionHelper.GetExpressionText(expression),\r
 184                                   null /* value */,\r
 185                                   htmlAttributes);\r
 186         }\r
 187 \r
 188         private static MvcHtmlString PasswordHelper(HtmlHelper htmlHelper, string name, object value, IDictionary<string, object> htmlAttributes) {\r
 189             return InputHelper(htmlHelper, InputType.Password, name, value, false /* useViewData */, false /* isChecked */, true /* setId */, true /* isExplicitValue */, htmlAttributes);\r
 190         }\r
 191 \r
 192         // RadioButton\r
 193 \r
 194         public static MvcHtmlString RadioButton(this HtmlHelper htmlHelper, string name, object value) {\r
 195             return RadioButton(htmlHelper, name, value, (object)null /* htmlAttributes */);\r
 196         }\r
 197 \r
 198         public static MvcHtmlString RadioButton(this HtmlHelper htmlHelper, string name, object value, object htmlAttributes) {\r
 199             return RadioButton(htmlHelper, name, value, new RouteValueDictionary(htmlAttributes));\r
 200         }\r
 201 \r
 202         public static MvcHtmlString RadioButton(this HtmlHelper htmlHelper, string name, object value, IDictionary<string, object> htmlAttributes) {\r
 203             // Determine whether or not to render the checked attribute based on the contents of ViewData.\r
 204             string valueString = Convert.ToString(value, CultureInfo.CurrentCulture);\r
 205             bool isChecked = (!String.IsNullOrEmpty(name)) && (String.Equals(htmlHelper.EvalString(name), valueString, StringComparison.OrdinalIgnoreCase));\r
 206             // checked attributes is implicit, so we need to ensure that the dictionary takes precedence.\r
 207             RouteValueDictionary attributes = htmlAttributes == null ? new RouteValueDictionary() : new RouteValueDictionary(htmlAttributes);\r
 208             if (attributes.ContainsKey("checked")) {\r
 209                 return InputHelper(htmlHelper, InputType.Radio, name, value, false, false, true, true /* isExplicitValue */, attributes);\r
 210             }\r
 211 \r
 212             return RadioButton(htmlHelper, name, value, isChecked, htmlAttributes);\r
 213         }\r
 214 \r
 215         public static MvcHtmlString RadioButton(this HtmlHelper htmlHelper, string name, object value, bool isChecked) {\r
 216             return RadioButton(htmlHelper, name, value, isChecked, (object)null /* htmlAttributes */);\r
 217         }\r
 218 \r
 219         public static MvcHtmlString RadioButton(this HtmlHelper htmlHelper, string name, object value, bool isChecked, object htmlAttributes) {\r
 220             return RadioButton(htmlHelper, name, value, isChecked, new RouteValueDictionary(htmlAttributes));\r
 221         }\r
 222 \r
 223         public static MvcHtmlString RadioButton(this HtmlHelper htmlHelper, string name, object value, bool isChecked, IDictionary<string, object> htmlAttributes) {\r
 224             if (value == null) {\r
 225                 throw new ArgumentNullException("value");\r
 226             }\r
 227             // checked attribute is an explicit parameter so it takes precedence.\r
 228             RouteValueDictionary attributes = htmlAttributes == null ? new RouteValueDictionary() : new RouteValueDictionary(htmlAttributes);\r
 229             attributes.Remove("checked");\r
 230             return InputHelper(htmlHelper, InputType.Radio, name, value, false, isChecked, true, true /* isExplicitValue */, attributes);\r
 231         }\r
 232 \r
 233         [SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures", Justification = "This is an appropriate nesting of generic types")]\r
 234         public static MvcHtmlString RadioButtonFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, object value) {\r
 235             return RadioButtonFor(htmlHelper, expression, value, null /* htmlAttributes */);\r
 236         }\r
 237 \r
 238         [SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures", Justification = "This is an appropriate nesting of generic types")]\r
 239         public static MvcHtmlString RadioButtonFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, object value, object htmlAttributes) {\r
 240             return RadioButtonFor(htmlHelper, expression, value, new RouteValueDictionary(htmlAttributes));\r
 241         }\r
 242 \r
 243         [SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures", Justification = "This is an appropriate nesting of generic types")]\r
 244         public static MvcHtmlString RadioButtonFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, object value, IDictionary<string, object> htmlAttributes) {\r
 245             return RadioButtonHelper(htmlHelper,\r
 246                                      ModelMetadata.FromLambdaExpression(expression, htmlHelper.ViewData).Model,\r
 247                                      ExpressionHelper.GetExpressionText(expression),\r
 248                                      value,\r
 249                                      null /* isChecked */,\r
 250                                      htmlAttributes);\r
 251         }\r
 252 \r
 253         private static MvcHtmlString RadioButtonHelper(HtmlHelper htmlHelper, object model, string name, object value, bool? isChecked, IDictionary<string, object> htmlAttributes) {\r
 254             if (value == null) {\r
 255                 throw new ArgumentNullException("value");\r
 256             }\r
 257 \r
 258             RouteValueDictionary attributes =\r
 259                 htmlAttributes == null ? new RouteValueDictionary()\r
 260                                        : new RouteValueDictionary(htmlAttributes);\r
 261 \r
 262             bool explicitValue = isChecked.HasValue;\r
 263             if (explicitValue) {\r
 264                 attributes.Remove("checked");    // Explicit value must override dictionary\r
 265             }\r
 266             else {\r
 267                 string valueString = Convert.ToString(value, CultureInfo.CurrentCulture);\r
 268                 isChecked = model != null &&\r
 269                             !String.IsNullOrEmpty(name) &&\r
 270                             String.Equals(model.ToString(), valueString, StringComparison.OrdinalIgnoreCase);\r
 271             }\r
 272 \r
 273             return InputHelper(htmlHelper, InputType.Radio, name, value, false /* useViewData */, isChecked ?? false, true /* setId */, true /* isExplicitValue */, attributes);\r
 274         }\r
 275 \r
 276         // TextBox\r
 277 \r
 278         public static MvcHtmlString TextBox(this HtmlHelper htmlHelper, string name) {\r
 279             return TextBox(htmlHelper, name, null /* value */);\r
 280         }\r
 281 \r
 282         public static MvcHtmlString TextBox(this HtmlHelper htmlHelper, string name, object value) {\r
 283             return TextBox(htmlHelper, name, value, (object)null /* htmlAttributes */);\r
 284         }\r
 285 \r
 286         public static MvcHtmlString TextBox(this HtmlHelper htmlHelper, string name, object value, object htmlAttributes) {\r
 287             return TextBox(htmlHelper, name, value, new RouteValueDictionary(htmlAttributes));\r
 288         }\r
 289 \r
 290         public static MvcHtmlString TextBox(this HtmlHelper htmlHelper, string name, object value, IDictionary<string, object> htmlAttributes) {\r
 291             return InputHelper(htmlHelper, InputType.Text, name, value, (value == null) /* useViewData */, false /* isChecked */, true /* setId */, true /* isExplicitValue */, htmlAttributes);\r
 292         }\r
 293 \r
 294         [SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures", Justification = "This is an appropriate nesting of generic types")]\r
 295         public static MvcHtmlString TextBoxFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression) {\r
 296             return htmlHelper.TextBoxFor(expression, (IDictionary<string, object>)null);\r
 297         }\r
 298 \r
 299         [SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures", Justification = "This is an appropriate nesting of generic types")]\r
 300         public static MvcHtmlString TextBoxFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, object htmlAttributes) {\r
 301             return htmlHelper.TextBoxFor(expression, new RouteValueDictionary(htmlAttributes));\r
 302         }\r
 303 \r
 304         [SuppressMessage("Microsoft.Design", "CA1006:DoNotNestGenericTypesInMemberSignatures", Justification = "This is an appropriate nesting of generic types")]\r
 305         public static MvcHtmlString TextBoxFor<TModel, TProperty>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, TProperty>> expression, IDictionary<string, object> htmlAttributes) {\r
 306             return TextBoxHelper(htmlHelper,\r
 307                                  ModelMetadata.FromLambdaExpression(expression, htmlHelper.ViewData).Model,\r
 308                                  ExpressionHelper.GetExpressionText(expression),\r
 309                                  htmlAttributes);\r
 310         }\r
 311 \r
 312         private static MvcHtmlString TextBoxHelper(this HtmlHelper htmlHelper, object model, string expression, IDictionary<string, object> htmlAttributes) {\r
 313             return InputHelper(htmlHelper, InputType.Text, expression, model, false /* useViewData */, false /* isChecked */, true /* setId */, true /* isExplicitValue */, htmlAttributes);\r
 314         }\r
 315 \r
 316         // Helper methods\r
 317 \r
 318         private static MvcHtmlString InputHelper(HtmlHelper htmlHelper, InputType inputType, string name, object value, bool useViewData, bool isChecked, bool setId, bool isExplicitValue, IDictionary<string, object> htmlAttributes) {\r
 319             name = htmlHelper.ViewContext.ViewData.TemplateInfo.GetFullHtmlFieldName(name);\r
 320             if (String.IsNullOrEmpty(name)) {\r
 321                 throw new ArgumentException(MvcResources.Common_NullOrEmpty, "name");\r
 322             }\r
 323 \r
 324             TagBuilder tagBuilder = new TagBuilder("input");\r
 325             tagBuilder.MergeAttributes(htmlAttributes);\r
 326             tagBuilder.MergeAttribute("type", HtmlHelper.GetInputTypeString(inputType));\r
 327             tagBuilder.MergeAttribute("name", name, true);\r
 328 \r
 329             string valueParameter = Convert.ToString(value, CultureInfo.CurrentCulture);\r
 330             bool usedModelState = false;\r
 331 \r
 332             switch (inputType) {\r
 333                 case InputType.CheckBox:\r
 334                     bool? modelStateWasChecked = htmlHelper.GetModelStateValue(name, typeof(bool)) as bool?;\r
 335                     if (modelStateWasChecked.HasValue) {\r
 336                         isChecked = modelStateWasChecked.Value;\r
 337                         usedModelState = true;\r
 338                     }\r
 339                     goto case InputType.Radio;\r
 340                 case InputType.Radio:\r
 341                     if (!usedModelState) {\r
 342                         string modelStateValue = htmlHelper.GetModelStateValue(name, typeof(string)) as string;\r
 343                         if (modelStateValue != null) {\r
 344                             isChecked = String.Equals(modelStateValue, valueParameter, StringComparison.Ordinal);\r
 345                             usedModelState = true;\r
 346                         }\r
 347                     }\r
 348                     if (!usedModelState && useViewData) {\r
 349                         isChecked = htmlHelper.EvalBoolean(name);\r
 350                     }\r
 351                     if (isChecked) {\r
 352                         tagBuilder.MergeAttribute("checked", "checked");\r
 353                     }\r
 354                     tagBuilder.MergeAttribute("value", valueParameter, isExplicitValue);\r
 355                     break;\r
 356                 case InputType.Password:\r
 357                     if (value != null) {\r
 358                         tagBuilder.MergeAttribute("value", valueParameter, isExplicitValue);\r
 359                     }\r
 360                     break;\r
 361                 default:\r
 362                     string attemptedValue = (string)htmlHelper.GetModelStateValue(name, typeof(string));\r
 363                     tagBuilder.MergeAttribute("value", attemptedValue ?? ((useViewData) ? htmlHelper.EvalString(name) : valueParameter), isExplicitValue);\r
 364                     break;\r
 365             }\r
 366 \r
 367             if (setId) {\r
 368                 tagBuilder.GenerateId(name);\r
 369             }\r
 370 \r
 371             // If there are any errors for a named field, we add the css attribute.\r
 372             ModelState modelState;\r
 373             if (htmlHelper.ViewData.ModelState.TryGetValue(name, out modelState)) {\r
 374                 if (modelState.Errors.Count > 0) {\r
 375                     tagBuilder.AddCssClass(HtmlHelper.ValidationInputCssClassName);\r
 376                 }\r
 377             }\r
 378 \r
 379             if (inputType == InputType.CheckBox) {\r
 380                 // Render an additional <input type="hidden".../> for checkboxes. This\r
 381                 // addresses scenarios where unchecked checkboxes are not sent in the request.\r
 382                 // Sending a hidden input makes it possible to know that the checkbox was present\r
 383                 // on the page when the request was submitted.\r
 384                 StringBuilder inputItemBuilder = new StringBuilder();\r
 385                 inputItemBuilder.Append(tagBuilder.ToString(TagRenderMode.SelfClosing));\r
 386 \r
 387                 TagBuilder hiddenInput = new TagBuilder("input");\r
 388                 hiddenInput.MergeAttribute("type", HtmlHelper.GetInputTypeString(InputType.Hidden));\r
 389                 hiddenInput.MergeAttribute("name", name);\r
 390                 hiddenInput.MergeAttribute("value", "false");\r
 391                 inputItemBuilder.Append(hiddenInput.ToString(TagRenderMode.SelfClosing));\r
 392                 return MvcHtmlString.Create(inputItemBuilder.ToString());\r
 393             }\r
 394 \r
 395             return tagBuilder.ToMvcHtmlString(TagRenderMode.SelfClosing);\r
 396         }\r
 397     }\r
 398 }\r