Do you have a control that displays international dates as specified in the system settings?
Take a look at the file datectrl.cpp and datectrl.h in the dbfbrows sample. It implements a date control for international dates.
With Objective Grid 5.0 the CGXDateTimeCtrl has been added (32-Bit only). Check out the class reference for CGXDateTimeCtrl for information about this cell type.
With Objective Grid 6.0 you can specify date formatting with CGXStyle::SetFormat(GX_FMT_DATE).
Example:
SetExpressionRowCol(nRow+1, 6, _T("01/01/88"));
SetStyleRange(CGXRange(nRow+1, 6),
CGXStyle().SetFormat(GX_FMT_DATE));
Note: Only the full version of Objective Grid does provide a date-time control.