DynamicDataDisplay Line Graph plotter with multiple data sources?

Question

I am trying to plot multiple curves in different color on my graph. I am currently using one plotter (not sure if that will work, and that is why I am posting a thread here), and here is my code:

if (_dataXChA != null && _dataXChA.Length > 1)
{
  EnumerableDataSource<double> xChA = new EnumerableDataSource<double>(_dataXChA);
  xChA.SetXMapping(xVal => xVal);

  if (_dataYChA != null && _dataYChA.Length == _dataXChA.Length)
  {
    EnumerableDataSource<double> yChA = new EnumerableDataSource<double>(_dataYChA);
    yChA.SetYMapping(yVal => yVal);
    CompositeDataSource dsChA = new CompositeDataSource(xChA, yChA);
    ((LineGraph)plotter.Children.ElementAt(startIndex)).DataSource = dsChA;                   
    plotter.FitToView();
  }
}

if (_dataXChB != null && _dataXChB.Length > 1)
{
  EnumerableDataSource<double> xChB = new EnumerableDataSource<double>(_dataXChB);
  xChB.SetXMapping(xVal => xVal);

  if (_dataYChB != null && _dataYChB.Length == _dataXChB.Length)
  {
    EnumerableDataSource<double> yChB = new EnumerableDataSource<double>(_dataYChB);
    yChB.SetYMapping(yVal => yVal);                    
    CompositeDataSource dsChB = new CompositeDataSource(xChB, yChB);
    ((LineGraph)plotter.Children.ElementAt(startIndex)).DataSource = dsChB;
    //LineGraph lgChA = plotter.AddLineGraph(dsChB, _dataBrushColorChB, 1, "Data");
    plotter.FitToView();
  }
}

The first curve should be in green, and the second curve should be in red. plotter is CharterPlotter But when I look at the graph,I only got one curve. Then I looked at the data, it seems the curve displays the data from second data source, but the color of the curve is green.

The constructor assigns the color like this:

LineGraph lgChA = plotter.AddLineGraph(dsChA, _dataBrushColorChA, 1, "Data");
LineGraph lgChB = plotter.AddLineGraph(dsChB, _dataBrushColorChB, 1, "Data");

where,

_dataBrushColorChA = Colors.Green;
_dataBrushColorChB = Colors.Red;

Basically, I only update the data points each time when event occurs, because I have tried AddLineGraph(), but it turned out to be very slow, so I only update the data points. So, anyone give me any pointers? How can I handle this multiple data source situation?

Answer 1

It looks like you are setting the data source for the same plotter child at startIndex for both channels:

((LineGraph)plotter.Children.ElementAt(startIndex)).DataSource = dsChA;

...

((LineGraph)plotter.Children.ElementAt(startIndex)).DataSource = dsChB;

The second assignment would cause the DataSource to be overridden by dsChB, which would make it only display one line.

Maybe the index should be different for A and B?