public void Move()
{
if (_topLeftHelperPoint != null)
{
_topLeftHelperPoint.X = _ellipse.TopLeft.X;
_topLeftHelperPoint.Y = _ellipse.TopLeft.Y;
}
if (_bottomRightHelperPoint != null)
{
_bottomRightHelperPoint.X = _ellipse.BottomRight.X;
_bottomRightHelperPoint.Y = _ellipse.BottomRight.Y;
}
_layer.Invalidate();
}