How to export List to Excel in C++

/* ------------------------------------------------------------
 * Tutorial 01
 *
 * This tutorial shows how to export list to Excel file in C++.
 * The list contains data from a SQL database.
 * The cells are formatted using a predefined format.
 * --------------------------------------------------------- */

#include "EasyXLS.h"
#include <conio.h>
#import "C:\Program Files\Common Files\System\ado\msado15.dll" \
no_namespace rename("EOF", "EndOfFile")

int main()
{
    printf("Tutorial 01\n----------\n");

    HRESULT hr ;

    // Initialize COM
    hr = CoInitialize(0);

    // Use the SUCCEEDED macro and get a pointer to the interface
    if (SUCCEEDED(hr))
    {
        // Create a pointer to the interface that exports Excel files
        EasyXLS::IExcelDocumentPtr workbook;
        hr = CoCreateInstance(__uuidof(EasyXLS::ExcelDocument),
                              NULL,
                              CLSCTX_ALL,
                              __uuidof(EasyXLS::IExcelDocument),
                              (void**) &workbook);

        if (SUCCEEDED(hr))
        {
            // Create the database connection
            _ConnectionPtr objConn;
            objConn.CreateInstance(__uuidof(Connection));
            objConn->Open("driver={sql server};server=(local);Database=Northwind;UID=sa;PWD=;",
                                   (BSTR) NULL, (BSTR) NULL, -1);

            WCHAR* sQueryString = L"SELECT TOP 100 CAST(Month(ord.OrderDate) AS varchar) + \
                                   '/' + CAST(Day(ord.OrderDate) AS varchar) + \
                                   '/' + CAST(year(ord.OrderDate) AS varchar) AS 'Order Date', \
                                   P.ProductName AS 'Product Name', O.UnitPrice AS Price, \
                                   CAST(O.Quantity AS varchar) AS Quantity, \
                                   O.UnitPrice * O. Quantity AS Value \
                                   FROM Orders AS ord, [Order Details] AS O, Products AS P \
                                   WHERE O.ProductID = P.ProductID AND O.OrderID = ord.OrderID";
            _variant_t sqlQueryString = sQueryString ;

            // Query the database
            _RecordsetPtr objRS = NULL;
            objRS.CreateInstance(__uuidof(Recordset));
            objRS->Open(sqlQueryString, _variant_t((IDispatch*)objConn, true),
                                   adOpenStatic, adLockOptimistic, adCmdText);

            // Create the list that stores the query values
            EasyXLS::IListPtr lstRows;
            CoCreateInstance(__uuidof(EasyXLS::List), NULL, CLSCTX_ALL,
                             __uuidof(EasyXLS::IList), (void**) &lstRows);

            // Add the report header row to the list
            EasyXLS::IListPtr lstHeaderRow;
            CoCreateInstance(__uuidof(EasyXLS::List), NULL, CLSCTX_ALL,
                             __uuidof(EasyXLS::IList), (void**) &lstHeaderRow);
            lstHeaderRow->addElement("Order Date");
            lstHeaderRow->addElement("Product Name");
            lstHeaderRow->addElement("Price");
            lstHeaderRow->addElement("Quantity");
            lstHeaderRow->addElement("Value");
            lstRows->addElement(_variant_t((IDispatch*)lstHeaderRow, true));

            VARIANT index;
            index.vt=VT_I4;
            FieldPtr field;

            // Add the query values from the database to the list
            while (!(objRS->EndOfFile))
            {
                EasyXLS::IListPtr  RowList;
                CoCreateInstance(__uuidof(EasyXLS::List), NULL, CLSCTX_ALL,
                                 __uuidof(EasyXLS::IList), (void**) &RowList);
                VARIANT value;

                for (int nIndex = 0; nIndex < 5; nIndex++)
                {
                    index.lVal = nIndex;
                    objRS->Fields->get_Item(index, &field);
                    field->get_Value (&value);
                    RowList->addElement(&value);
                }
                lstRows->addElement(_variant_t((IDispatch*)RowList, true));

                // Move to the next record
                objRS->MoveNext();
            }

            // Create an instance of the class used to format the cells
            EasyXLS::IExcelAutoFormatPtr xlsAutoFormat;
            CoCreateInstance(__uuidof(EasyXLS::ExcelAutoFormat), NULL, CLSCTX_ALL,
                             __uuidof(EasyXLS::IExcelAutoFormat), (void**) &xlsAutoFormat);
            xlsAutoFormat->InitAs(AUTOFORMAT_EASYXLS1);

            // Export list to Excel file
            printf("Writing file C:\\Samples\\Tutorial01 - export List to Excel.xlsx.");
            hr = workbook->easy_WriteXLSXFile_FromList_2("C:\\Samples\\Tutorial01 - export List to Excel.xlsx",
                                                         _variant_t((IDispatch*)lstRows, true),
                                                         _variant_t((IDispatch*)xlsAutoFormat,true),
                                                         "Sheet1");

            // Confirm export of Excel file
            _bstr_t sError = workbook->easy_getError();
            if (strcmp(sError, "") == 0)
            {
                printf("\nFile successfully created. Press Enter to Exit...");
            }
            else
            {
                printf("\nError encountered: %s", (LPCSTR)sError);
            }

            // Close the Recordset object
            objRS->Close();

            // Close database connection
            objConn->Close();

            // Dispose memory
            workbook->Dispose();
        }
        else
        {
            printf("Object is not available!");
        }
    }
    else
    {
        printf("COM can't be initialized!");
    }

    // Uninitialize COM
    CoUninitialize();

    _getch();
    return 0;
}