Cvi and Excel Help ?

Question

Hi All
Is there a way of writing to an Excel Spread sheet when that same spread sheet is open with windows explorer?
Something like a shared connection.
Kind Regards
Shako
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Answer 1

You can obtain a handle to an active Excel application and connect to it, reading and writing to the active sheet.
As an example, I modified Excel2000dem sample application that comes with CVI to obtain this behaviour: modifications are in this callback:
// OpenAppFile
int CVICALLBACK OpenAppFile (int panel, int control, int event,
void *callbackData, int eventData1, int eventData2)
HRESULT error = 0;
char fileName[MAX_PATHNAME_LEN];
switch (event) {
case EVENT_COMMIT:
if (!ExcelWorkbooksHandle)
// Get Workbooks
error = Excel_GetProperty (ExcelAppHandle, NULL, Excel_AppWorkbooks,
CAVT_OBJHANDLE, &ExcelWorkbooksHandle);
if (error<0)
goto Error;
// EXCLUDED LINES IN CASE OF CONNECTION TO AN ALREADY OPENED FILE
// Open existing Workbook
// GetProjectDir (fileName);
// strcat(fileName, "\\exceldem.xls");
// error = Excel_WorkbooksOpen (ExcelWorkbooksHandle, NULL, fileName, CA_DEFAULT_VAL,
// CA_DEFAULT_VAL, CA_DEFAULT_VAL,
// CA_DEFAULT_VAL, CA_DEFAULT_VAL,
// CA_DEFAULT_VAL, CA_DEFAULT_VAL,
// CA_DEFAULT_VAL, CA_DEFAULT_VAL,
// CA_DEFAULT_VAL, CA_DEFAULT_VAL,
// CA_DEFAULT_VAL, &ExcelWorkbookHandle);
// if (error<0)
// goto Error;
// // Get Active Workbook Sheets
// error = Excel_GetProperty (ExcelAppHandle, NULL, Excel_AppSheets,
// CAVT_OBJHANDLE, &ExcelSheetsHandle);
// if (error<0)
// goto Error;
// // Get First Sheet
// error = Excel_SheetsItem (ExcelSheetsHandle, NULL, CA_VariantInt(1),
// &ExcelWorksheetHandle);
// if (error<0)
// goto Error;
// // Make First Sheet Active - should already be active
// error = Excel_WorksheetActivate (ExcelWorksheetHandle, NULL);
// if (error<0)
// goto Error;
// END OF EXCLUDED LINES
// New command to obtain a handle to the active sheet
error = Excel_GetProperty (ExcelAppHandle, NULL, Excel_AppActiveSheet, CAVT_OBJHANDLE, &ExcelWorksheetHandle);
if (error<0)
goto Error;
// Update UIR
UpdateUIRDimming(panel);
else
MessagePopup(APP_WARNING, "Document already open");
break;
return 0;
Error:
ClearObjHandle (&ExcelWorksheetHandle);
ClearObjHandle (&ExcelSheetsHandle);
ClearObjHandle (&ExcelWorkbookHandle);
ClearObjHandle (&ExcelWorkbooksHandle);
if (error < 0)
ReportAppAutomationError (error);
return 0;
To use the example, modify the code as stated, open the document in Excel, run the program and select "Connect to Excel", next select "Open file" (the modified callback) and you can read / write to the file both from interactively and from the program.
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