protected override void OnElementChanged(ElementChangedEventArgs <DrawingView> e)
{
base.OnElementChanged(e);
if (Control == null && Element != null)
{
canvasView = new SKCanvasView(Forms.Forms.NativeParent)
{
BackgroundColor = Element.BackgroundColor.ToNative()
};
canvasView.Show();
Element.Points.CollectionChanged += OnPointsCollectionChanged;
SetNativeControl(canvasView);
}
if (e.OldElement != null)
{
canvasView !.EvasCanvas.DeleteEventAction(EvasObjectCallbackType.MouseDown, MouseDown);
canvasView.EvasCanvas.DeleteEventAction(EvasObjectCallbackType.MouseUp, MouseUp);
canvasView.EvasCanvas.DeleteEventAction(EvasObjectCallbackType.MouseMove, MouseMove);
canvasView.PaintSurface -= OnPaintSurface;
}
if (e.NewElement != null)
{
canvasView !.PaintSurface += OnPaintSurface;
canvasView.EvasCanvas.AddEventAction(EvasObjectCallbackType.MouseDown, MouseDown);
canvasView.EvasCanvas.AddEventAction(EvasObjectCallbackType.MouseUp, MouseUp);
canvasView.EvasCanvas.AddEventAction(EvasObjectCallbackType.MouseMove, MouseMove);
}
}
protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
{
base.OnElementPropertyChanged(sender, e);
if (e.PropertyName == DrawingView.PointsProperty.PropertyName)
{
canvasView !.EvasCanvas.DeleteEventAction(EvasObjectCallbackType.MouseUp, MouseUp);
LoadPoints();
canvasView.EvasCanvas.AddEventAction(EvasObjectCallbackType.MouseUp, MouseUp);
}
}
protected override void Dispose(bool disposing)
{
if (disposed)
{
return;
}
disposed = true;
if (Element != null)
{
Element.Points.CollectionChanged -= OnPointsCollectionChanged;
canvasView !.EvasCanvas.DeleteEventAction(EvasObjectCallbackType.MouseDown, MouseDown);
canvasView.EvasCanvas.DeleteEventAction(EvasObjectCallbackType.MouseUp, MouseUp);
canvasView.EvasCanvas.DeleteEventAction(EvasObjectCallbackType.MouseMove, MouseMove);
canvasView.PaintSurface -= OnPaintSurface;
}
base.Dispose(disposing);
}