ZippyV said:

The code in the View:

<%: Html.ListBoxFor(Function(m) m.NewsItem.NewsCategories, Model.Categories)%>

I have had my share of headache's with the HTML.ListBoxFor

 

One of the gotacha's is; don't put any ViewData[] or other stuff on your form that interferes with the name, ID's ect.

 

Here's how I use em, that I found works:

 

The SalesOpsManagers is just an IList<string>

 

<%

= Html.ListBoxFor(model => model.SalesOpsManagers, (IEnumerable<SelectListItem>)ViewData["TerritorySalesOpsManagers"], new { style = "width:250px;" })%>

 

And the viewdata is in the form of a selectlistitem, doesnt need to be multiselectlist item

 

hope this helps you