Silverlight 在新创建的项目上获取TreeViewItem

必须有比下面更好的方法来获取childItem

    TaskItem task = (sender as Canvas).DataContext as TaskItem;
    TaskItem child = Tasks.CreateTask("New task", task);
    TreeViewItem item = treeView.ItemContainerGenerator.ContainerFromItem(task) as TreeViewItem;            

    item.UpdateLayout();
    TreeViewItem childItem = null;
    foreach (var i in item.GetDescendantContainers())
    {
        if (i.GetItem() == child)
            childItem = i;
    }

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出于某些原因，item.ItemGenerator.ContainerFromItemchild无法工作必须是由于刚刚创建的项

项容器生成是异步的，因此您不能假设添加项后容器将立即存在。您需要将处理程序附加到事件，以便在容器生成完成时通知您的代码

WPF博士的博客文章很好地描述了该问题，并提供了使用StatusChanged的示例：

private void AddScooby()
{
    _scooby = new Character("Scooby Doo");
    Characters.Add(_scooby);
    CharacterListBox.ItemContainerGenerator.StatusChanged
        += OnStatusChanged;
}

private void OnStatusChanged(object sender, EventArgs e)
{
    if (CharacterListBox.ItemContainerGenerator.Status
        == GeneratorStatus.ContainersGenerated)
    {
        CharacterListBox.ItemContainerGenerator.StatusChanged
            -= OnStatusChanged;
        ListBoxItem lbi = CharacterListBox.ItemContainerGenerator
            .ContainerFromItem(_scooby) as ListBoxItem;
        if (lbi != null)
        {
            lbi.IsSelected = true;
        }
    }
}