private void AddRootFolder(object sender, RoutedEventArgs e)
        {
            FolderBrowserDialog dialog = new FolderBrowserDialog();

            if (dialog.ShowDialog() != System.Windows.Forms.DialogResult.OK)
            {
                return;
            }

            try
            {
                if (MyPlayer.Source != null)
                {
                    new AlertMessage("You should stop media player first.", String.Empty).ShowDialog();
                    return;
                }
                _libraryManager.AddRootPath(dialog.SelectedPath);
                ShowLibraryList(sender, e);
            }
            catch (Exception ex)
            {
                new AlertMessage(ex.Message, ex.StackTrace).ShowDialog();
            }
        }