ASP.NET MVC - Can't bind array to view model - asp.net-mvc

Question

I have a view model with a from that includes a set of checkboxes. I need the check boxes to map to an array when binding in the post back method of my controller.
Here's the view model.
#model TMDM.Models.TestSeriesCreateViewModel
#{
ViewBag.Title = "Create";
}
<h2>Create a Test Series</h2>
#using (Html.BeginForm()) {
#Html.ValidationSummary(true)
<fieldset>
<div class="editor-label">
#Html.LabelFor(model => model.Title)
</div>
<div class="editor-field">
#Html.EditorFor(model => model.Title)
#Html.ValidationMessageFor(model => model.Title)
</div>
<h3>Which Test Collections are in this Test Series?</h3>
<div class="editor-field">
#{
var i = 0;
foreach (var testCollection in Model.TestCollections)
{
<input type="checkbox" id="ChosenTestCollectionIds[#i]" name="ChosenTestCollectionIds[#i]" value="#testCollection.Id" />
<span>#testCollection.Title</span>
<br />
i++;
}
}
</div>
<p>
<input type="submit" value="Save" class="medium green awesome" />
#Html.ActionLink("Cancel", "Index", "TestSeries", null, new { #class = "medium black awesome" })
</p>
</fieldset>
The form is rendering fine, I've checked the source and each output check box has a different number for their id and name fields.
<input type="checkbox" id="ChosenTestCollectionIds[0]" name="ChosenTestCollectionIds[0]" value="5" />
<input type="checkbox" id="ChosenTestCollectionIds[1]" name="ChosenTestCollectionIds[1]" value="6" />
//etc...
Here is the view model.
public class TestSeriesModel
{
public int Id { get; set; }
public string Title { get; set; }
}
public class TestSeriesCreateViewModel : TestSeriesModel
{
public List<ITestCollectionDataObject> TestCollections { get; set; }
public int[] ChosenTestCollectionIds { get; set; }
}
Problem I'm having is that when the form posts back the ChosenTestCollectionIds array comes back null. What am I doing wrong here?
ANSWER
I've worked out how to do it:
<input type="checkbox" id="[#i]" name="ChosenTestCollectionIds" value="#testCollection.Id" />

Answer 1

<input type="checkbox" id="[#i]" name="ChosenTestCollectionIds" value="#testCollection.Id" />

Answer 2

I always come back to Phil Haack's post about model binding a list. In addition, I always define my own index because my user's will alter the list on the client side then post back the changes.
http://haacked.com/archive/2008/10/23/model-binding-to-a-list.aspx

Answer 3

Set the name of the input types to all be the same. You can also create a custom model binder if you are trying to bind a more complex model than just a list. Here is an excellent article on the different ways to bind to your models
Various Model Binding techniques