Filling a tree with linq group

var instancesByPrograms = instances
    .GroupBy(instance => instance.ProgramsDescription)
    .OrderBy(grouped => grouped.Key);

foreach (var instanceGroup in instancesByPrograms)
{
    var parentNode = new TreeNode(
        instanceGroup.Key,
        instanceGroup.Select(instance =>
        {
            var node = new TreeNode(instance.Description);
            node.Tag = instance;
            return node;
        }).ToArray());

    treeView.Nodes.Add(parentNode);
}