导航离开并返回页面后，获取当前背景音频的播放时间- UWP

private TimeSpan audioPlaybackPosition;

private void Page_NavigatedFrom(object sender, NavigationEventArgs e)
{
    // 保存当前背景音频的播放时间
    audioPlaybackPosition = BackgroundMediaPlayer.Current.Position;
}

private void Page_NavigatedTo(object sender, NavigationEventArgs e)
{
    // 恢复背景音频的播放
    BackgroundMediaPlayer.Current.Play();

    // 将播放时间设置为之前保存的时间
    BackgroundMediaPlayer.Current.Position = audioPlaybackPosition;
}