c# - TreeViewItem は BackgroundWorker で更新できません

Question

を更新するこのメソッドがありますTreeView。私が使用しない場合は、BackgroundWorkerすべて正常に動作します。しかし、そうするとTreeViewItem更新されませんが、それは DataContex の変更です。これもうまくいきます：item.IsEnabled = false;

private void twSports_Expanded(object sender, RoutedEventArgs e)    
{       
TreeViewItem item = e.OriginalSource as TreeViewItem;
TreeLeaf leaf = item.DataContext as TreeLeaf;  var bgWorker = new BackgroundWorkerOnGrid(gridPartitions);
bgWorker.DoWork += delegate(object s, DoWorkEventArgs args)
{              
    if (leaf.Item != null)
    {
        if (leaf.Item.GetType() == typeof(SportType))
        {
            SportType sport = leaf.Item as SportType;
            args.Result = LoadSportPartitions(sport);
        }
        if (leaf.Item.GetType() == typeof(SportPartition))
        {
            SportPartition partition = leaf.Item as SportPartition;
            args.Result = LoadSportPartitions(partition);
        }
    }
};

bgWorker.RunWorkerCompleted += delegate(object s, RunWorkerCompletedEventArgs args)
{
    List<SportPartition> partitions = args.Result as List<SportPartition>;

    if (partitions != null)
    {
        leaf.LoadChilds(partitions.ToArray());    //it doesn't work
        item.IsEnabled = false; //it works
    }

    (s as BackgroundWorkerOnGrid).Dispose();
};

bgWorker.RunWorkerAsync(leaf.Item);}

何か案は？