유리상자 속 이야기

public class AnimatedImage : Image
{
    BitmapDecoder decoder = null;
    private int Count = 0;
    private System.Timers.Timer Timer = new System.Timers.Timer();
    private object TimerLock = new object();

    public double Interval { get { return this.Timer.Interval; } set { this.Timer.Interval = value; } }
    public bool IsPlaying { get; set; }

    public AnimatedImage()
        : base() {
        this.IsPlaying = false;
        this.Interval = 100;
        this.Timer.Elapsed += new System.Timers.ElapsedEventHandler(Timer_Elapsed);
    }




    //------------------------- 
    // Image 변경되었을 경우 
    //------------------------- 
    protected override void OnPropertyChanged(DependencyPropertyChangedEventArgs e) {
        if (e.Property.Name == "Source") {
            if (e.NewValue != null &&
                (e.OldValue == null || (e.NewValue.ToString() != e.OldValue.ToString()))) {
                this.Stop();
                try {
                    decoder = new BitmapDecoder(new Uri(e.NewValue.ToString()),
                        BitmapCreateOptions.None, BitmapCacheOption.None);
                } catch { }
                this.Start();
            }
        }
        base.OnPropertyChanged(e);
    }



    //------------------------- 
    // Start Animation 
    //------------------------- 
    private void Start() {
        lock (TimerLock) {
            if (this.decoder != null && this.decoder.Frames.Count > 1) {
                if (this.IsPlaying == false) {
                    this.IsPlaying = true;
                    this.Timer.Start();
                }
            }
        }
    }



    //------------------------- 
    // Stop Animation 
    //------------------------- 
    private void Stop() {
        lock (TimerLock) {
            this.IsPlaying = false;
            this.Timer.Stop();
        }
    }



    //------------------------- 
    // Timer Procedure 
    //------------------------- 
    void Timer_Elapsed(object sender, System.Timers.ElapsedEventArgs e) {
        this.Dispatcher.BeginInvoke(new Action(delegate {
            Count = ++Count % decoder.Frames.Count;
            this.Source = decoder.Frames[Count];
            this.InvalidateArrange();
        }), null);
    }
}