plot - Get Chart.Series points to an array C# -

i creating program shows fourier transform , plots points graph. i'm trying user input , each time enter number array, update whole graph based on points.

because chart displays transformed values, need points chart.series, convert them using inverse fourier, clear chart, add values obtained chart, add new value inserted user, run fourier again , add plots graph.

i wondering if there way in c# [x,y] values of plot , [y] values that.

--edit--

 private void inputbutton_click(object sender, eventargs e)     {         // messagebox.show("the calculations complete", "my application",         //                    messageboxbuttons.okcancel, messageboxicon.asterisk);         // information here graph         // save data array         // clear series         // add new data freq array         double[] freq = { 2, 4, 6, 7, 5, 3, 15, 2 };          double[] = new double[freq.length];          = halffouriertransform(freq, freq.length);          hftchart.series[0].points.clear();          for(int = 0; < freq.length - 1; i++)         {             hftchart.series["hft"].points.addy(a[i]);         }          // work new data each time         // hftchart.series[0].points.clear();       }