MVC model data that is rendered in the view is null when posted back - asp.net-mvc

Question

I have seen similar questions to this and followed the routine answer which is to ensure all model data is rendered in the HTML.
I have done that and the model is rendered in the view with #Html.HiddenFor() but when the posting back to the controller there are no items in the list ?
The view will happily render multiple items in the list, but List<Item> Items in the posted data is always an empty list (not null)
Model
public class ItemCollection
{
public List<string> AvailiableActions { get; set; }
public List<Item> Items { get; set; }
}
public class Item
{
public int Id { get; set; }
public string Name { get; set; }
public string SelectedAction { get; set; }
}
View
#model ItemCollection
#using (Html.BeginForm("myAction", "myController", FormMethod.Post))
{
<fieldset>
<div>
#Html.HiddenFor(m => Model.Items)
#Html.DisplayNameFor(x => x.AvailiableActions)
<table>
#{
foreach (var item in Model.Items)
{
#Html.HiddenFor(m => item)
#Html.HiddenFor(s => item.Id)
<tr>
<td>#item.Name</td>
<td>#Html.DropDownList(item.SelectedAction, new SelectList(Model.AvailiableActions))</td>
</tr>
}
}
</table>
</div>
</fieldset>
}
Controller
[HttpPost]
private ActionResult myAction(ItemCollection model)
{
if (model.Items.Count() == 0)
{
// this is true.. something is wrong......
}
}

Answer 1

You cannot use a foreach loop to render controls for a collection. It renders duplicate id and name attributes without the necessary indexers to bind to a collection. Use a for loop
for (int i = 0; i < Model.Items.Count; i++)
{
<tr>
<td>
#Html.HiddenFor(m => m.Items[i].Id)
#Html.DisplayFor(m => m.Items[i].Name)
</td>
<td>#Html.DropDownList(m => m.Items[i].SelectedAction, new SelectList(Model.AvailiableActions))</td>
</tr>
}
Note your view also included #Html.HiddenFor(m => Model.Items) and #Html.HiddenFor(m => item) which would also have failed because item is a complex object and you can only bind to value types. You need to remove both.

Answer 2

Instead of iterating over all items to make sure the index is added to the generated output, you may consider using EditorTemplates (an example on an other site).
EditorTemplates allow you to specify a template for a single Item in \Views\Shared\EditorTemplates\Item.cshtml:
#model Item
#{
var options= (List<string>)ViewData["Options"];
}
<tr>
<td>
#Html.HiddenFor(m => m.Id)
#Html.DisplayFor(m => m.Name)
</td>
<td>#Html.DropDownList(m => m.SelectedAction, new SelectList(options))</td>
</tr>
Then you may simply change your view to:
#model ItemCollection
#using (Html.BeginForm("myAction", "myController", FormMethod.Post))
{
<fieldset>
<div>
<table>
#Html.EditorFor(m => m.Items, new {Options = Model.AvailiableActions })
</table>
</div>
</fieldset>
}