Question

I’m making a page with LongListboxSelector which shows audiotracks. Each item has Button “play” and TextBlock with artist and title info. I’m using BackgroundAudioPlayer. My desire is to make next: when track is playing – image of the Button is “pause”, when track is over – make its Button image “play”, and make the next track’s Button image “pause” (next track plays automatically). I tried somethink likes this

    public AudioListPage()
    {
        InitializeComponent();
        BackgroundAudioPlayer.Instance.PlayStateChanged += Instance_PlayStateChanged;
    }

    void Instance_PlayStateChanged(object sender, EventArgs e)
    {
        if (BackgroundAudioPlayer.Instance.PlayerState == PlayState.Stopped)
        {
            IEnumerable buttons = AudioLLS.Descendants<Coding4Fun.Phone.Controls.RoundButton>();
            var test = new BitmapImage(new Uri(@"/Images/appbar.transport.pause.rest.png", UriKind.Relative));

            foreach (Coding4Fun.Phone.Controls.RoundButton item in buttons)
            {                   
                if (item.ImageSource == test)
                {
                    MessageBox.Show("in new image");
                    item.ImageSource = new BitmapImage(new Uri(@"/Images/appbar.transport.play.rest.png", UriKind.Relative));
                    buttons.GetEnumerator().MoveNext();
                    item.ImageSource = new BitmapImage(new Uri(@"/Images/appbar.transport.pause.rest.png", UriKind.Relative));
                }

            }
        }
    }

PlayState.Stopped fires when track ends, and next is going to start.
I tried to take all buttons in my LLS using LinqToVisualTree helper in IEnumerable buttons = AudioLLS.Descendants<Coding4Fun.Phone.Controls.RoundButton>() and compare their images with test. But as I can see – I’m doing it wrong, because in block if(item.ImageSource == test) my app never comes. Please, tell me, what I’m doing wrong? And if my way to solve the problem is bad – please, tell me how to do it in easy way.

Answer 1

I added two property to my audio model

    private bool isPlaing = false;
    public bool IsPlaing 
    { 
        get { return isPlaing; }
        set 
        { 
            isPlaing = value;
            OnPropertyChanged("IsPlaing");
            if (IsPlaing) Image = @"/Images/appbar.transport.pause.rest.png";
            else if (!IsPlaing) Image = @"/Images/appbar.transport.play.rest.png";
        }
    }
    private string image = @"/Images/appbar.transport.play.rest.png";
    public string Image { get { return image; } set { image = value; OnPropertyChanged("Image"); } }

and in playerStateChanged i added

        if (BackgroundAudioPlayer.Instance.PlayerState == PlayState.Stopped)
        {
            for (int i = 0; i < AudioList.Count; i++)
            {
                if (AudioList[i].Url1 == currTrack)
                {
                    AudioList[i].IsPlaing = false;
                    currTrack = AudioList[i + 1].Url1;
                    AudioList[i + 1].IsPlaing = true;
                    break;
                }

                }
            }
            BackgroundAudioPlayer.Instance.Play();
        }

In this way I solved my problem. As I can see – all works fine.