/// <summary>
/// 收藏，若已收藏过，提示错误
/// </summary>
private void FavoriteButton_Click(object sender, RoutedEventArgs e)
{
if (SelectedItem != null)
{
if (UserDB.AddFavorite(SelectedItem))
{
NotifyPopup notifyPopup = new NotifyPopup("收藏成功!");
notifyPopup.Show();
}
else
{
NotifyPopup notifyPopup = new NotifyPopup("收藏已存在!");
notifyPopup.Show();
}
}
}