How to plot MULTIPLE LineSeries on an OxyPlot chart?

Question

I apologize for asking so many OxyPlot questions, but I seem to be really struggling with using the OxyPlot chart control.

My project is in WPF format so I was originally using a hosted WINFORMS chart and that worked like a charm and did absolutely everything I needed it to until I needed to overlay a WPF element on top of the hosted winform chart. Due to the "AirSpace" issue, I was not able to see the WPF element that I put on top of the hosted chart no matter what I did. That is when I decided to go with OxyPlot, which is giving me quite a few headaches so far.

Here is my origional question! that I asked over at CodePlex. I don't seem to be getting much help over there so I am trying again here.

My question is:

Does anyone know how to plot MULTIPLE LineSeries onto a Plot??

My approach so far:

I am taking a c# List array and adding a new copy of the LineSeries that holds new data to be plotted. My code:

    // Function to plot data
    private void plotData(double numWeeks, double startingSS)
    {

        // Initialize new Salt Split class for acess to data variables
        Salt_Split_Builder calcSS = new Salt_Split_Builder();
        calcSS.compute(numWeeks, startingSS, maxDegSS);

        // Create the OxyPlot graph for Salt Split
        OxyPlot.Wpf.PlotView plot = new OxyPlot.Wpf.PlotView();

        var model = new PlotModel();

        // Add Chart Title
        model.Title = "Salt Split Degradation";

        // Create new Line Series
        LineSeries linePoints = new LineSeries() { StrokeThickness = 1, MarkerSize = 1, Title = numWeeks.ToString() + " weeks" };

        // Add each point to the new series
        foreach (var point in calcSS.saltSplitCurve)
        {
            DataPoint XYpoint = new DataPoint();
            XYpoint = new DataPoint(point.Key, point.Value * 100);
            linePoints.Format("%", XYpoint.Y);
            linePoints.Points.Add(XYpoint);
        }

        listPointAray.Add(linePoints);

        // Define X-Axis
        var Xaxis = new OxyPlot.Axes.LinearAxis();
        Xaxis.Maximum = numWeeks;
        Xaxis.Minimum = 0;
        Xaxis.Position = OxyPlot.Axes.AxisPosition.Bottom;
        Xaxis.Title = "Number of Weeks";
        model.Axes.Add(Xaxis);

        //Define Y-Axis
        var Yaxis = new OxyPlot.Axes.LinearAxis();
        Yaxis.MajorStep = 15;
        Yaxis.Maximum = calcSS.saltSplitCurve.Last().Value * 100;
        Yaxis.MaximumPadding = 0;
        Yaxis.Minimum = 0;
        Yaxis.MinimumPadding = 0;
        Yaxis.MinorStep = 5;
        Yaxis.Title = "Percent Degradation";
        model.Axes.Add(Yaxis);

        // Add Each series to the
        foreach (var series in listPointAray)
        {
            LineSeries newpoints = new LineSeries();
            newpoints = linePoints;
            model.Series.Add(newpoints);
        }

        // Add the plot to the window
        plot.Model = model;
        SaltSplitChartGrid.Children.Add(plot);

    }

My code works the first time I press my "Graph Data" button, but fails on consecutive attempts with the following error:

The element cannot be added, it already belongs to a Plot Model

The following plot is the type of plot I would like to produce (it worked fine using WinForms Chart control):

I would like a new line with a new color to be plotted each time I run the method.

Answer 1

This is how I've created multi lines on an OxyPlot chart before, the key is creating a set of DataPoints for each series - called circlePoints & linePoints in the following example code, these are then bound to the CircleSeries and LineSeries:

var xAxis = new DateTimeAxis
{
    Position = AxisPosition.Bottom,
    StringFormat = Constants.MarketData.DisplayDateFormat,
    Title = "End of Day",
    IntervalLength = 75,
    MinorIntervalType = DateTimeIntervalType.Days,
    IntervalType = DateTimeIntervalType.Days,
    MajorGridlineStyle = LineStyle.Solid,
    MinorGridlineStyle = LineStyle.None,
};

var yAxis = new LinearAxis
{
    Position = AxisPosition.Left,
    Title = "Value",
    MajorGridlineStyle = LineStyle.Solid,
    MinorGridlineStyle = LineStyle.None
};

var plot = new PlotModel();
plot.Axes.Add(xAxis);
plot.Axes.Add(yAxis);

var circlePoints = new[]
{
    new ScatterPoint(DateTimeAxis.ToDouble(date1), value1),
    new ScatterPoint(DateTimeAxis.ToDouble(date2), value2),
};

var circleSeries =  new ScatterSeries
{
    MarkerSize = 7,
    MarkerType = MarkerType.Circle,
    ItemsSource = circlePoints
};

var linePoints = new[]
{
    new DataPoint(DateTimeAxis.ToDouble(date1), value1),
    new DataPoint(DateTimeAxis.ToDouble(date2), value2),
};

var lineSeries = new LineSeries
{
    StrokeThickness = 2,
    Color = LineDataPointColor,
    ItemsSource = linePoints
};

plot.Series.Add(circleSeries);
plot.Series.Add(lineSeries);