将xlsx转换为xls问题

Question

I am trying to convert a .xlsx file to .xls and it seems to be working fine, however when I open the .xls file I get a warning message "

The file you are trying to open 'filename', is in a different format than specified by the file extension.

Verify that the file is not corrupted and >from a trusted source before opening the >file. Do you want to open the file now?"....

Everything looks fine when I open it, but I do not understand why this is happening. My next step in this program is to import the data from the xls into SQL, but I am afraid this will cause issues for that.

Here is the line of code where I call the SaveAs method to change the file extension of the file.

wb.SaveAs("filename.xls", FileFormat: Microsoft.Office.Interop.Excel.XlFileFormat.xlOpenXMLWorkbook);

I initially just had

wb.SaveAs("filename.xls"); 

and after I got the error I did some more digging around and found the xlOpenXMLWorkbook , but does not seem to help.

Any info that could help me understand why this is happening would be much appreciated.

Answer 1

To save as spreadsheet (OpenXml Format, .xlsx ), use XlFileFormat.xlOpenXMLWorkbook :

wb.SaveAs("filename.xlsx", FileFormat: Microsoft.Office.Interop.Excel.XlFileFormat.xlOpenXMLWorkbook);

To save as Excel 1997-2003 format (Biff, .xls ), use XlFileFormat.xlExcel8 :

wb.SaveAs("filename.xls", FileFormat: Microsoft.Office.Interop.Excel.XlFileFormat.xlExcel8);

Make sure you set the appropriate extension (.xlsx or .xls), otherwise, you have the error you described.

See also my answer here Excel Interop Save as is giving compatibility checker in excel 2007