给TreeView添加PreviewMouseDoubleClick事件，并在时间内拦截事件路由即可。具体如下：

<TreeView
PreviewMouseDoubleClick="TreeManuscript_PreviewMouseDoubleClick"/>

private void TreeManuscript_PreviewMouseDoubleClick(object sender, System.Windows.Input.MouseButtonEventArgs e)
{
e.Handled = true;
}