I am writing a Media Folder Viewer.

When I call the ChildrenAsList on a DynamicMedia I get an List<DynamicBackingItem>.

How do I group the items into groups of 4?

@using umbraco.MacroEngines;
@using umbraco.cms.businesslogic.media;

@helper BuildTable(dynamic mediaList)
{
    <table border="0">
    <tbody>
    @foreach (var item in mediaList)
    {
        <tr>
            <td align="center"><img src="@item.GetProperty("umbracoFile").Value" alt="" /></td>
        </tr>
    }
    </tbody>
    </table>
}
@helper BuildTable2(dynamic mediaList)
{
    <table border="0">
    <tbody>
    @foreach (var group in mediaList.InGroupsOf(4))
    {
        <tr>
        @foreach(var item in group)
        {
            <td align="center"><img src="@((DynamicMedia)item).umbracoFile" alt="" /></td>
        }
        </tr>
    }
    </tbody>
    </table>
}

@{
    if (String.IsNullOrEmpty(@Parameter.MediaFolder))
    {
        <div>A Folder has not been selected</div>
    }
    var folderId = @Parameter.MediaFolder;
    var media = Model.MediaById(folderId);
    var items = media.ChildrenAsList;
    if(items.GetType() == typeof(DynamicNull))
    {
        <div>Cannot Find the Folder (@folderId)</div>
    }
    else if(items.Count <= 0)
    {
        <div>Folder is Empty</div>
    }
    else
    {
        @BuildTable(items);
    }
}