Thank you, Narcís.
This problem has been fixed.

I used scFastLine as param of function AddSeries,
namely myTChart.AddSeries(scFastLine), AddNullXY did not have effect as
its name imply.
Latter, I used scLine instead of scFastLine, then AddNullXY took effect.

Thanks.

I'm using Visual C++, MFC, and Visual Studio 7.0 with TChart ActiveX Pro V7. I want the series to break as exception occurs. These codes look as following: if (exeption) series(0).AddNullXY(current_time, y, ""); else series(0).AddXY(current_time, y, "", color); The series isn't broken and still disp...