BCGControlBar Pro for MFC
void CBCGPChartSurfaceSeries::EnableLevelRangeInLegendLabel ( BOOL  bEnable = TRUE)

Defines how level values are displayed in the chart legend.

If this option is TRUE, a legend entry displays minimum and maximum level values in format %.2G - %.2G.

Otherwise a legend entry displays only minimum level values.

A custom value format can be set in m_strLegendLevelValueFormat.