Creating an Excel file from VC++

[mawajo]

Hello, I am using VC++ and would like to create a formatted file that is compatible with Excel (something more the just tab delimited). Does anyone know of a spec for .xls files or have any suggestions on this?

Thanks,
mawajo

 

[Mike S.]

This may be useful.

* Security : DEV.

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The information in this article applies to:



- Microsoft Visual C++, 32-bit Editions, version 5.0

- Microsoft Excel 97 for Windows

- Microsoft Excel for Windows 95, versions 7.0, 7.0a

- Microsoft Excel for Windows, versions 5.0, 5.0a, 5.0c

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SUMMARY

=======



This article demonstrates how to determine the version of a Microsoft Excel

Workbook (.xls).



MORE INFORMATION

================



Microsoft Excel saves data using structured storage. In particular, it

creates a data stream called "Workbook" (previously just "Book") where

it saves the contents starting with a BOF (beginning of file) record. This

record contains useful attributes of the workbook, as well as the version.

The following Microsoft Visual C++ code demonstrates how to open the file,

read it, and return the version number based on the BOF.



1. Create a new "Win32 Console Application" in Microsoft Developer Studio.



2. Add a C++ Source File (.cpp) to the project and add the following code

to the source file:



#include<windows.h>

#include<iostream.h> // My additions



// BOF record from Microsoft Excel

typedef struct _xlbof

{

char bofMarker; // Should be 0x09



char vers; // Version indicator for biff2, biff3, and biff4

// = 0x00 -> Biff2

// = 0x02 -> Biff3

// = 0x04 -> Biff4

// = 0x08 -> Biff5/Biff7/Biff8



char skip[2]; // Unspecified



short int vers2; // Version number

// 0x0500 -> Biff5/Biff7

// 0x0600 -> Biff8



short int dt; // Substream type (not used in this example)



short int rupBuild; // Internal build identifier

short int rupYear; // Internal Build year

} XLBOF;





//* XLVersionFromFile() ******************************************

//* Returns

//* n for BiffN

//* i.e. 8 for Biff8 (Microsoft Excel 97)

//*

//* Negative if an error occurs

//****************************************************************



int XLVersionFromFile(char *filename) {

// Translate filename to Unicode

WCHAR wcFilename[1024];

int i = mbstowcs(wcFilename, filename, strlen(filename));

wcFilename = 0;



IStorage *pStorage;

HRESULT hr;

XLBOF xlbof;



// Open the document as an OLE compound document

hr = ::StgOpenStorage(wcFilename, NULL,

STGM_READ | STGM_SHARE_EXCLUSIVE, NULL, 0, &pStorage);



if(!FAILED(hr)) {

// Open the data-stream where Microsoft Excel stores the data

IStream *pStream;

hr = pStorage->OpenStream(L"Workbook", NULL,

STGM_READ | STGM_SHARE_EXCLUSIVE, 0, &pStream);



// If "Workbook" does not exist, try "Book"

if(FAILED(hr)) {

hr = pStorage->OpenStream(L"Book", NULL,

STGM_READ | STGM_SHARE_EXCLUSIVE, 0, &pStream);

}

if(!FAILED(hr)) {

// Read the relevant BOF information

DWORD dwCount; // bytes read

pStream->Read(&xlbof, sizeof(XLBOF), &dwCount);



// Let go of the IStream pointer

pStream->Release();

}

else return -2;



// Let go of the IStorage pointer

pStorage->Release();

}

else return -1;



// Determine which version to return

if(xlbof.vers != 0x08) return (xlbof.vers + 4) / 2;

else {

switch(xlbof.vers2) {

case 0x0500: // Either Biff5 or Biff7

// Biff7's rupYear is at least 1994

if(xlbof.rupYear< 1994) return 5;



// Check for specific builds of Microsoft Excel 5

switch(xlbof.rupBuild) {

case 2412: // XL5a

case 3218: // XL5c

case 3321: // NT XL5

return 5;

default:

return 7;

}



case 0x0600: return 8;

}

}



// Version not recognized. Perhaps there is a newer version.

return -3;

}



void main()

{

int iretVal = 0;

iretVal = XLVersionFromFile("C:\Test.xls");

//Adapt the filename to your example

cout<< "The Excel Version is "<< iretVal<< "nnr";

return;

}



3. In the main()function, you may need to modify the path and filename of

the Microsoft Excel workbook in the following line of code:



iretVal = XLVersionFromFile("C:\Test.xls");
This message was edited by on 2002-09-17 12:01