1.導入Excel類型庫
使用Visual C++的擴展指令#import導入Excel類型庫:
#import "C://Program Files//Common Files//microsoft shared//OFFICE14//MSO.DLL" / 
    rename("RGB","MsoRGB") / 
    rename("SearchPath","MsoSearchPath") 
#import "C://Program Files//Common Files//Microsoft Shared//VBA//VBA6//VBE6EXT.OLB" 
#import "C://Program Files//Microsoft Office//Office14//EXCEL.EXE" / 
    rename( "DialogBox", "ExcelDialogBox" ) / 
    rename( "RGB", "ExcelRGB" ) / 
    rename( "CopyFile", "ExcelCopyFile" ) / 
    rename( "ReplaceText", "ExcelReplaceText" ) / 
    exclude( "IFont", "IPicture" ) no_dual_interfaces 
#import指令會從指定的可執行文件,動態鏈接庫等COM組件中導出類型庫(type lib),在Debug和Release臨時目錄中生成對應的類型庫頭文件(type lib header file),以供C++程序使用。如以上三條指令在編譯后會生成excel.tlh, mso.lh和vbetext.olb三個頭文件,可以在Debug和Release目錄中找到。
2.訪問Excel暴露的COM對象
下面是一段比較完整的訪問Excel的實例代碼。首先用生成的數據填充單元格,然后用這些單元格的數據生成了一個圖表(Chart):
try
{ 
    Excel::_ApplicationPtr pExcelApp; 
    HRESULT hr = pExcelApp.CreateInstance(L"Excel.Application"); 
    ATLASSERT(SUCCEEDED(hr)); 
    pExcelApp->Visible = true;   // make Excel's main window visible 
    Excel::_WorkbookPtr pWorkbook = pExcelApp->Workbooks->Open(lpszPathName);  // open excel file 
    Excel::_WorksheetPtr pWorksheet = pWorkbook->ActiveSheet; 
    pWorksheet->Name = L"Chart Data"; 
    Excel::RangePtr pRange = pWorksheet->Cells; 
    const int nplot = 100; 
    const double xlow = 0.0, xhigh = 20.0; 
    double h = (xhigh-xlow)/(double)nplot; 
    pRange->Item[1][1] = L"x";  // read/write cell's data 
    pRange->Item[1][2] = L"f(x)"; 
    for (int i=0;i<nplot;++i) 
    { 
        double x = xlow+i*h; 
        pRange->Item[i+2][1] = x; 
        pRange->Item[i+2][2] = sin(x)*exp(-x); 
    } 
    Excel::RangePtr pBeginRange = pRange->Item[1][1]; 
    Excel::RangePtr pEndRange = pRange->Item[nplot+1][2]; 
    Excel::RangePtr pTotalRange =  
        pWorksheet->Range[(Excel::Range*)pBeginRange][(Excel::Range*)pEndRange]; 
    Excel::_ChartPtr pChart = pExcelApp->ActiveWorkbook->Charts->Add(); 
    // refer to : 
    // http://msdn.microsoft.com/en-us/library/microsoft.office.tools.excel.chart.chartwizard(v=vs.80).aspx 
    pChart->ChartWizard( 
        (Excel::Range*)pTotalRange, 
        (long)Excel::xlXYScatter, 
        6L, 
        (long)Excel::xlColumns, 
        1L,1L, 
        true, 
        L"My Graph", 
        L"x",L"f(x)"); 
    pChart->Name = L"My Data Plot"; 
    pWorkbook->Close(VARIANT_TRUE);  // save changes 
    pExcelApp->Quit(); 
} 
catch (_com_error& error) 
{ 
    ATLASSERT(FALSE); 
    ATLTRACE2(error.ErrorMessage()); 
}
在這段代碼中,Excel::_ApplicationPtr , Excel::_WorkbookPtr 和 Excel::_WorksheetPtr 等均是Visual C++ 編譯器根據#import指令自動生成的智能指針,實際上就是C++模板類_com_ptr_t<T>的typedef,其定義可在excel.tlh等類型庫頭文件中找到。
另外,由于#import指令中沒有指定raw_interface_only修飾符,Visual C++對Excel的COM接口進行了適當的封裝,以簡化COM接口屬性和方法的調用,并且將HRESULT返回值都轉換成了C++異常,因此,上面的這段代碼不需要每一步都堅持HRESULT,而是改為捕獲C++異常。