When defining a series programmatically you can find out what series color will be drawn in using the Loaded event, like the following:
•C#
DataSeries ds = new DataSeries() { ValuesSource = new double[] { 1, 2, 3 } };
ds.PlotElementLoaded += (s, e2) // fired for each plot element in data series
{
PlotElement pe = (PlotElement)s;
SolidColorBrush sb = pe.Fill as SolidColorBrush;
if( sb!=null)
Debug.WriteLine(sb.Color);
};
chart.Data.Children.Add(ds);