title: How to plot MULTIPLE LineSeries on an OxyPlot chart?
body: <p>I apologize for asking so many OxyPlot questions, but I seem to be really struggling with using the OxyPlot chart control. </p>
  
  <p>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. </p>
  
  <p>Here is my <a href="https://archive.codeplex.com/?p=oxyplot" rel="nofollow noreferrer">origional question</a>! that I asked over at CodePlex. I don't seem to be getting much help over there so I am trying again here. </p>
  
  <p>My question is:</p>
  
  <p>Does anyone know how to plot MULTIPLE LineSeries onto a Plot??</p>
  
  <p>My approach so far: </p>
  
  <p>I am taking a c# List array and adding a new copy of the LineSeries that holds new data to be plotted. My code:</p>
  
  <pre><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);
  
      }
  </code></pre>
  
  <p>My code works the first time I press my "Graph Data" button, but fails on consecutive attempts with the following error:  </p>
  
  <blockquote>
    <p>The element cannot be added, it already belongs to a Plot Model</p>
  </blockquote>
  
  <p>The following plot is the type of plot I would like to produce (it worked fine using WinForms Chart control):</p>
  
  <p><a href="https://i.stack.imgur.com/xO0Y0.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/xO0Y0.jpg" alt="Image"></a>
  </p>
  
  <p>I would like a new line with a new color to be plotted each time I run the method.</p>