Excel::_ApplicationPtr pXL;
pXL.CreateInstance(L"Excel.Application");
pXL->Visible[ 0 ] = VARIANT_TRUE;
WorkbooksPtr pBooks = pXL->Workbooks;
_WorkbookPtr pBook  = pBooks->Add((long)xlWorksheet);
_WorksheetPtr pSheet = pXL->ActiveSheet;
pSheet->Name = "Sheet1";

_ChartPtr chartptr = pXL->Charts->Add();
chartptr->ChartType = xlLineMarkers;
chartptr->Name = "chart1";
chartptr->SetSourceData(pSheet->Range["A1:A15"],xlColumns);
//после следующей строки указатель на диаграмму меняется, т.к. я привязываю его к Sheet
chartptr->Location(xlLocationAsObject,"Sheet1");

ActiveSheet->ChartObjects

_WorksheetPtr wp = pXL->ActiveSheet;
chartptr_ = wp->ChartObjects( 1 );

Worksheets("Sheet1").ChartObjects( 1 ).Chart

Excel::_ChartPtr test, act;
Excel::ChartObjectPtr chp;
Excel::ChartObjectsPtr zzz;

zzz = pSheet->ChartObjects();
		
		if((zzz->Count)> 0 )
		{							
		   chp = zzz->Item(zzz->Count);
                        //chp = pSheet->ChartObjects( 1 );//без разницы...
                        test = chp->Chart;
                        chp->Activate();
                        act = pBook->ActiveChart;
                          }