Collections.Generic.Dictionary<TKey,Tvalue> model binding from Viewmodel to controller - asp.net-mvc-2

Question

i have this problem :
when i try to post submit from a View to a httppost actionResult i get always a null value.
this is my code :
public class WhiteListViewModel
{
public string Badge { get; set; }
public IEnumerable<string> Selezioni { get; set; }
public IEnumerable<bool> Abilitazioni { get; set; }
}
public ActionResult WhiteList()
{
return View( "Whitelist", MasterPage, new WhitelistViewModel());
}
[HttpPost]
public ActionResult WhiteListp(IEnumerable<WhiteListViewModel> Whitelist )
{
bool[] abilitato = new bool[Whitelist.Single().Abilitazioni.Count()];
string[] selezione = new string[Whitelist.Single().Selezioni.Count()];
...
}
<%# Page Title="" Language="C#" MasterPageFile="~/Views/Shared/SiteR.Master" Inherits="System.Web.Mvc.ViewPage<IEnumerable<_21112010.ViewModel.WhiteListViewModel>>" %>
<asp:Content ID="Content1" ContentPlaceHolderID="TitleContent" runat="server">
WhiteList
</asp:Content
<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server">
<h2>WhiteList</h2>
<table style="width:100%;">
<thead>
</thead>
<tbody >
<%using ( Html.BeginForm( ) )
{%>
<% foreach ( var item in Model ){%>
<tr style="width:100%;">
<td >
<%: item.Badge%>
</td>
<%foreach ( var abit in item.Abilitazioni ){%>
<td >
<%: Html.CheckBoxFor(c=>abit/*, new { onchange = "this.form.submit();" } */ )%>
<%: Html.ValidationMessageFor(c => abit) %>
</td>
<% } %>
<%} %>
<td style=" width:1px;" >
<%: Html.HiddenFor(model=>item.Badge) %>
<% foreach (var sel in item.Selezioni) {%>
<%: Html.HiddenFor(c=>sel) %>
<%} %>
</td>
</tr> <%}%>
</tbody>
<tfoot>
</tfoot >
</table>
<input type="submit" value="Salva ed Esci" style = "background-color:Gray; color:#F6855E; font-weight:bold; border:1px solid black; height:20px;" />
<%:Html.ActionLink( "Aggiungi Badge", "AggiungiBadge")%>
<% } %>
</div>
</asp:Content>
where am I doing wrong?

Answer 1

The binding process will attempt to map the IEnumerable to the parameter Whitelist of the HttpPost action. However, I'm fairly sure that this is failing because the binding process has no information to tie the submitted fields to the expected parameter "Whitelist".
You have a few options:
Try using TryUpdateModel() in your action;
Creating a custom ModelBinder. This will allow you to interogate the submitted Model and build your IEnumerable prior to it being passed to the action parameter;
You could interogate the submitted fields using the FormCollection object from within the action. This is a little messy and not ideal;
Simplify your view.
Personally, I would look at the ModelBinder. If anything, this would give you a better insight into why the Model may not be binding to the action parameter.