public GraphHeaderView ()
{
dv = new DrawingView(new RectangleF(0,0, chartWidth, chartHeight), 0, 0, 0);
this.AddSubview(dv );
}
public GraphHeaderView ()
{
dv = new DrawingView (new CGRect (0, 0, chartWidth, chartHeight), 0, 0, 0);
this.AddSubview (dv);
}