Rotating image every .5 second in another thread

Question

I want to make a small Wheel of Fortune game, but I have issues making an event that rotates the image

This is the code I have now, but it only seems to run the _thread once

    private readonly Timer _timer;
    private Thread _thread;
    private int _angle;

    public MainWindow()
    {
        InitializeComponent();
        _timer = new Timer(500);
        _timer.Elapsed += RotateWheelEvent;
        _timer.Start();

        _angle = 0;

        SetupRotationThread();
        _thread.Start();
    }

        public void RotateWheelEvent(object sender, EventArgs args)
    {
        _thread.Abort();
        _angle = _angle + 15;
        _thread.Start();
    }

    public void SetupRotationThread()
    {
        var rotatetransform = new RotateTransform(_angle);

        _thread = new Thread(
            delegate()
                {
                    ImageWheel.Dispatcher.Invoke(
                        System.Windows.Threading.DispatcherPriority.SystemIdle,
                        TimeSpan.FromSeconds(1),
                        new Action(
                            delegate()
                                {
                                    ImageWheel.RenderTransformOrigin = new Point(0.5, 0.5);
                                    ImageWheel.RenderTransform = rotatetransform;
                                }
                            ));
                });
    }

Answer 1

At worst you should just use a DispatcherTimer in your code-behind:

var timer = new DispatcherTimer
{
    Interval = TimeSpan.FromSeconds(0.5)
};

timer.Tick += (s, e) => ((RotateTransform)ImageWheel.RenderTransform).Angle += 15;
timer.IsEnabled = true;

But there's really no need for that at all. You can just set up a Storyboard in your XAML. Something like:

<Image x:Name="image" RenderTransformOrigin="0.5,0.5" ...>
    <Image.RenderTransform>
        <RotateTransform/>
    </Image.RenderTransform>
    <Image.Triggers>
        <EventTrigger RoutedEvent="Loaded">
            <BeginStoryboard>
                <Storyboard Duration="00:00:00.5" RepeatBehavior="Forever">
                    <DoubleAnimation Storyboard.TargetName="image" Storyboard.TargetProperty="(Image.RenderTransform).(RotateTransform.Angle)" By="15"/>
                </Storyboard>
            </BeginStoryboard>
        </EventTrigger>
    </Image.Triggers>
</Image>

Some of that syntax may not be quite right (on linux so cannot check), but you get the idea. You've overly complicated something very simple.

Answer 2

You could just use a System.Threading.Timer instead of a System.Timer spawning a new thraed each time.

        private System.Threading.Timer _timer;
        private int _angle;

        public MainWindow()
        {
            InitializeComponent();
              _timer = new System.Threading.Timer((o) => 
              {
                  _angle += 15;
                  Dispatcher.Invoke(DispatcherPriority.Background, (Action)delegate
                  {
                      ImageWheel.RenderTransformOrigin = new Point(0.5, 0.5);
                      ImageWheel.RenderTransform = new RotateTransform(_angle);
                  }); 
              }, null, 500, 500);
        }

However its not clear why you are threading this at all, you seem to be starting a thread that just invokes code back to the UI thread, I dont see any work this thread needs to do.

So all I think you need is this

private readonly Timer _timer;
private int _angle;

    public MainWindow()
    {
        InitializeComponent();
        _timer = new Timer(500);
        _timer.Elapsed += RotateWheelEvent;
        _timer.Start();
        _angle = 0;
    }

    public void RotateWheelEvent(object sender, EventArgs args)
    {
        Dispatcher.Invoke(DispatcherPriority.Background, (Action)delegate
        {
            _angle += 15;
            ImageWheel.RenderTransformOrigin = new Point(0.5, 0.5);
            ImageWheel.RenderTransform = new RotateTransform(_angle);
        }); 
    }