categoryAxis.GapWidth = 3;
   categoryAxis.Labels.Add("A");
   categoryAxis.Labels.Add("B");
   categoryAxis.Labels.Add("C");
   categoryAxis.Labels.Add("D");
   model.Axes.Add(categoryAxis);
   var linearAxisSoft = new LinearAxis();
   linearAxisSoft.Key = "y1";
   linearAxisSoft.AbsoluteMinimum = 0;
   linearAxisSoft.Position = AxisPosition.Left;
   model.Axes.Add(linearAxisSoft);
   var linearAxisSoft1 = new LinearAxis();
   linearAxisSoft1.Key = "y2";
   linearAxisSoft1.AbsoluteMinimum = 0;
   linearAxisSoft1.Position = AxisPosition.Right;
   model.Axes.Add(linearAxisSoft1);
   BarSeries barSeries = new BarSeries();
   barSeries.XAxisKey = "y1";
   barSeries.YAxisKey = "x";
   barSeries.Background = OxyColors.Green;
   barSeries.FillColor = OxyColors.YellowGreen;
   barSeries.IsStacked = true;
   
   barSeries.Items.Add(new BarItem (60,0));
   barSeries.Items.Add(new BarItem(30, 1));
   barSeries.Items.Add(new BarItem(60, 2));
   barSeries.Items.Add(new BarItem(30, 3));
   model.Series.Add(barSeries);
   LineSeries lineSeries = new LineSeries();
   lineSeries.MarkerType = MarkerType.Square;
   lineSeries.MarkerFill = OxyColors.Red;
   lineSeries.MarkerSize = 20;
   lineSeries.XAxisKey = "x";
   lineSeries.YAxisKey = "y2";
   lineSeries.Points.Add(new DataPoint(0, 40));
   lineSeries.Points.Add(new DataPoint(1, 30));
   lineSeries.Points.Add(new DataPoint(2, 60));
   lineSeries.Points.Add(new DataPoint(3, 30));
   model.Series.Add(lineSeries);
   return model;