Doing Thangs

Billy.cs

public static class DispatcherHelper
{
    public static void DelayInvoke(this Dispatcher dispatcher, TimeSpan ts, Action action)
    {
        DispatcherTimer delayTimer = new DispatcherTimer();
        delayTimer.Interval = ts;
        delayTimer.Tick += (s, e) =>
        {
            delayTimer.Stop();
            action();
        };
        delayTimer.Start();
    }
}

// Using it:
// Over 1.5s duration with a 25ms step function
for(int i=0; i < 1500; i += 25) {
    Dispatcher.DelayInvoke(TimeSpan.FromMilliseconds(i), //animate at from i ms until next animation (at i+25)
                           new Action(() =>
                           {
                                // your R,G,B will be determined to be the linear progression from your colour to white
                                // over 1500/25 (60) steps. There's like a billion ways to do this, just google a bit and you'll figure it out
                                yourLabel.ForegroundColor = new SolidColorBrush(Color.FromArgb(100, R, G, B)); 
                           }));
}