public override void DrawRect(CGRect dirtyRect)
{
var g = Graphics.FromCurrentContext();
g.Clear(backColor);
cs.ChartArea = this.ClientRectangle;
AddData();
SetPlotArea(g);
cs.AddChartStyle(g);
dc.AddLines(g, cs);
lg.AddLegend(g, dc, cs);
g.Dispose();
}