title: MVC hidden fields not posting back
body: <p>I am using an EditorFor on a list of <code>ComponentParameter</code>s (shown below).  The editor template switches based on the value, and the datetime isn't working.  When I look at the HTML before postback, the values are there, but in the <code>List&lt;ComponentParameter&gt;</code> inside the model, the spots corresponding to the datetimes are null.</p>
  
  <pre><code>public class ComponentParameter
  {
      public string Value { get; set; }
      public string Description { get; set; }
      public string Type { get; set; }
      public bool Optional { get; set; }
  }
  </code></pre>
  
  <p>EditorTemplate:</p>
  
  <pre><code>@switch (Model.Type.ToLowerInvariant())
  {
  case "datetime":
          Html.RenderPartial("ParameterHeader", Model); 
  &lt;div class="grid_4"&gt;
      @{
          DateTime value;
          if (!DateTime.TryParse(Model.Value, out value))
          {
              value = DateTime.Today + TimeSpan.FromHours(6);
          }
      }
      // Commenting out the next 2 lines causes the value to post back
      &lt;div class="grid_9"&gt;@Html.TextBox("", value.ToString("MM/d/yyyy"), new { @class = "date-picker autotooltip " + Model.RequiredClass, @data_mwtooltip = Model.Description })&lt;/div&gt;
      @Html.TextBox("", value.ToString("hh:mm tt"), new {@class="time-picker"})
      @Html.HiddenFor(x =&gt; x.Value, new { @class = "input-time-picker" })
      @Html.HiddenFor(x =&gt; x.Optional)
      @Html.HiddenFor(x =&gt; x.Description)
      @Html.HiddenFor(x =&gt; x.Type)
  &lt;/div&gt;
          break;
  case "string":
      &lt;div class="grid_12"&gt;
          @{ Html.RenderPartial("ParameterHeader", @Model); }
  @Html.TextBoxFor(x =&gt; x.Value, new { @class = "autotooltip " + Model.RequiredClass, @data_mwtooltip = Model.Description })
  @Html.HiddenFor(x =&gt; x.Optional)
  @Html.HiddenFor(x =&gt; x.Description)
  @Html.HiddenFor(x =&gt; x.Type)
      &lt;/div&gt;
          break;
  }
  </code></pre>
  
  <p>Html:</p>
  
  <pre><code>&lt;div class="grid_4"&gt;
  &lt;div class="grid_9"&gt;
  &lt;span class="ui-spinner ui-widget ui-widget-content ui-corner-all"&gt;
  &lt;input id="ComponentList_0__ComponentParameterList_0_" class="time-picker ui-spinner-input valid" type="text" value="06:00 AM" name="ComponentList[0].ComponentParameterList[0]" aria-valuenow="1357041600000" autocomplete="off" role="spinbutton"&gt;
  &lt;a class="ui-spinner-button ui-spinner-up ui-corner-tr ui-button ui-widget ui-state-default ui-button-text-only" tabindex="-1" role="button" aria-disabled="false"&gt;
  &lt;a class="ui-spinner-button ui-spinner-down ui-corner-br ui-button ui-widget ui-state-default ui-button-text-only" tabindex="-1" role="button" aria-disabled="false"&gt;
  &lt;/span&gt;
  &lt;input id="ComponentList_0__ComponentParameterList_0__Value" class="input-time-picker" type="hidden" value="07/11/2013 06:00 AM" name="ComponentList[0].ComponentParameterList[0].Value"&gt;
  &lt;input id="ComponentList_0__ComponentParameterList_0__Optional" type="hidden" value="False" name="ComponentList[0].ComponentParameterList[0].Optional"&gt;
  &lt;input id="ComponentList_0__ComponentParameterList_0__Description" type="hidden" value="Start Time" name="ComponentList[0].ComponentParameterList[0].Description"&gt;
  &lt;input id="ComponentList_0__ComponentParameterList_0__Type" type="hidden" value="datetime" name="ComponentList[0].ComponentParameterList[0].Type"&gt;
  &lt;/div&gt;
  &lt;div class="grid_12"&gt;
  &lt;label&gt;
  &lt;input id="ComponentList_0__ComponentParameterList_5__Value" class="autotooltip paramRequired required" type="text" value="" name="ComponentList[0].ComponentParameterList[5].Value" data-mwtooltip="Attention Line" title=""&gt;
  &lt;input id="ComponentList_0__ComponentParameterList_5__Optional" type="hidden" value="False" name="ComponentList[0].ComponentParameterList[5].Optional"&gt;
  &lt;input id="ComponentList_0__ComponentParameterList_5__Description" type="hidden" value="Attention Line" name="ComponentList[0].ComponentParameterList[5].Description"&gt;
  &lt;input id="ComponentList_0__ComponentParameterList_5__Type" type="hidden" value="string" name="ComponentList[0].ComponentParameterList[5].Type"&gt;
  &lt;/div&gt;
  </code></pre>