private void MyCanvas_RegionsInvalidated(CanvasVirtualControl sender, CanvasRegionsInvalidatedEventArgs args)
{
foreach (var region in args.InvalidatedRegions)
{
using (var ds = MyCanvas.CreateDrawingSession(region))
{
if (virtualBitmap != null)
{
ds.DrawImage(virtualBitmap, region, region);
}
}
}
}