Null Data
Each SRGraphData object has a flag that allows the data content of that item to be marked as null or invalid. Chart types that detect a null data item may choose to ignore it completely or to generate some form of exception if the data is absolutely required in that position. To flag a data item as null, use the SetNull() function:
Line and Scatter charts ignore null data by default. A line is drawn from the preceding point to the following point. This behavior can be changed by calling
pD->GetStyle()-> SetBreakLinesOnNull(TRUE).
Then the line is not drawn, leaving a break in the curve connecting the data points.
NOTE >> For Scatter charts, flag both x and y data objects as null.