private void MagnifyBox_MouseMove(object sender, MouseEventArgs e)
{
if (dragOn)
{
currentP = e.GetPosition(null);
double x0 = System.Convert.ToDouble(this.GetValue(Canvas.LeftProperty));
double y0 = System.Convert.ToDouble(this.GetValue(Canvas.TopProperty));
ApplyTranslationTransform(currentP.X - beginP.X, currentP.Y - beginP.Y);
beginP = currentP;
UpdateMagnifyMapCenter();
}
}