MVC3: Portions of Model Not Reconstituted on Postback - asp.net-mvc-3

Question

Portions of my models are not being correctly reconstructed on postback.
Models
public class DemographicsModel
{
public List<QuestionModel> Questions { get; set; }
}
public abstract class QuestionModel
{
[HiddenInput(DisplayValue = false)]
public int ID { get; set; }
[HiddenInput(DisplayValue = false)]
public string Title { get; set; }
}
public abstract class ChooseQuestionModel : QuestionModel
{
public abstract List<SelectListItem> Items { get; set; }
}
public class ChooseManyQuestionModel : ChooseQuestionModel
{
[Required]
[DataType("CheckBoxList")]
public override List<SelectListItem> Items { get; set; }
}
Views
ChooseManyQuestionModel.cshtml
#model X.Y.Z.ChooseManyQuestionModel
<div class="Form Wide NoLabel">
<div class="Title">#this.Model.Title</div>
#Html.TypeStamp()
#Html.EditorFor(m => m.ID)
#Html.EditorFor(m => m.Title)
#Html.EditorFor(m => m.Items)
</div>
CheckBoxList.cshtml
#model IEnumerable<SelectListItem>
#if (!this.Model.IsNullOrEmpty())
{
foreach (var item in this.Model)
{
<div>
#Html.HiddenFor(m => item.Value)
#Html.HiddenFor(m => item.Text)
#Html.CheckBoxFor(m => item.Selected)
#Html.LabelFor(m => item.Selected, item.Text)
</div>
}
}
I believe the issue lies within CheckBoxList.cshtml since these items are not being re-constituted on postback.
HTML Output
<div class="Form Wide NoLabel">
<div class="Title">Question title displays here?</div>
<input id="Questions_1___xTypeStampx_" name="Questions[1]._xTypeStampx_" type="hidden" value="Hrxh2HjDRorBAZWo18hsC0OvbJwyswpDkfTBfNF2NC8=" />
<input data-val="true" data-val-number="The field ID must be a number." data-val-required="The ID field is required." id="Questions_1__ID" name="Questions[1].ID" type="hidden" value="76" />
<input id="Questions_1__Title" name="Questions[1].Title" type="hidden" value="Question title displays here?" />
<div>
<input id="Questions_1__Items_item_Value" name="Questions[1].Items.item.Value" type="hidden" value="148" />
<input id="Questions_1__Items_item_Text" name="Questions[1].Items.item.Text" type="hidden" value="Organization Type 1" />
<input data-val="true" data-val-required="The Selected field is required." id="Questions_1__Items_item_Selected" name="Questions[1].Items.item.Selected" type="checkbox" value="true" /><input name="Questions[1].Items.item.Selected" type="hidden" value="false" />
<label for="Questions_1__Items_item_Selected">Organization Type 1</label>
</div>
</div>
</div>
Controller
public class AccountController : BaseController
{
public ActionResult Demographics()
{
return this.View(new DemographicsModel());
}
[HttpPost]
public ActionResult Demographics(DemographicsModel model)
{
return this.View(model);
}
}
On postback, the DemographicsModel is populated with the correct types (I'm using MvcContrib to handle abstract type binding). The List<Question> is populated with all of the correct data including the ID and Title of each question from the hidden fields. However, List<SelectListItem> within each question is set to null.
Update 1
The issue is definitely occurring because the fields are not named correctly. For instance, the "item" field names are being generated like this:
Questions_1__Items_item_Value
When they should really look like this (addition of item index and removal of erroneous "item"):
Questions_1__Items_1__Value
Similarly, the field IDs are being generated like this (addition of item index and removal of erroneous "item"):
Questions[1].Items.item.Value
Instead of:
Questions[1].Items[0].Value
Using Fiddler with the correct IDs being posted back, the model is constructed correctly with all radio buttons and checkboxes in place.

Answer 1

Try the following.
In ChooseManyQuestionModel.cshtml, change #Html.EditorFor(m => m.Items) to:
#Html.EditorForModel(m => m.Items)
Then, in CheckBoxList.cshtml, change #model IEnumerable<SelectListItem> to:
#model SelectListItem
Finally, in each item, modify each lambda expression, and change item to m, then remove the foreeach loop. This will allow the Editor to iterate through the collection, and should give you correct id generation for each element.

Answer 2

When foreach loop is used the ids generated in HTML are all same.
When for look is used the ids generated with the for loops index so binding is happening correctly and all the data is available after post back.

Answer 3

In this scenario, it seems the Helper class is not doing what you want it to do. I would suggest writing your own helper class to name your inputs exactly as you require them to be.