WPF How to animate a property based on a custom event?-CodePudding

I'm trying to create a simple change in the background color of a border based on a timer.

I have this XAML:(That I pretty much copied from

However, what I want to do is to trigger the animation based on a custom event.

In the code behind I made a timer with a 1000ms interval. I want to trigger the animation on the timer's 'Elapsed' event.

        public partial class LedIndicator : UserControl
    {
        private System.Timers.Timer _timer;
              

        public Timer Timer { get => _timer; set => _timer = value; }

        public LedIndicator()
        {
            InitializeComponent();
           
            Timer = new System.Timers.Timer
            {
                AutoReset = true,
                Interval = 1000
            };
            Timer.Elapsed  = OnTimerElapsed;
            Timer.Start();
        }

        public void OnTimerElapsed(object? sender, System.Timers.ElapsedEventArgs e)
        {
            Debug.WriteLine($"Timer elapsed");
        }
    }

I wrapped the timer in a Property in the hope of somehow exposing its Elapse event to the XAML. But I have no idea how to do it.

CodePudding user response：

Here is a rough example

Create a storyboard in code somewhere:

private myAnimation = new ColorAnimation(Colors.LightGreen, new Duration(new TimeSpan(0, 0, 1)), FillBehavior.Stop);
myAnimation.AutoReverse = true;

Setup the timer:

private System.Threading.Timer animationTimer = new Timer(_ => 
{
    //need dispatcher to execute on UI thread
    Dispatcher.Invoke(() => 
    {
       ledColor.BeginAnimation(Button.BackgroundProperty, myAnimation);
    });
}, 0, 1000); //start immediately, and elapse every 1 second

CodePudding user response：

This is a small modification of @Ginger Ninja's answer to a working example.

When I tried his answer out, I got an exception saying that you can't animate the background property of type Brush with ColorAnimation.

After some Googleing, I found