Excel interop - saving my newly created spreadsheet throws an exception

Question

I am using C# to create a spreadsheet, here is the code:

try
{
    _excel = new Excel.Application();
    _excel.Visible = false;
    _workbook = _excel.Workbooks.Add( Type.Missing );
    _worksheet = (Excel.Worksheet)_workbook.Sheets[1];
    createColumnHeaders();
    _workbook.SaveCopyAs( savePath );
}
catch (Exception ex)
{
       Logger.Error( "Error creating spreadsheet: {0}", ex.Message );
}
finally
{
    // Cleanup
}

This runs nicely, saves the sheet into the savePath. However, if I change SaveCopyAs() to

SaveAs( savePath, 
        Excel.XlFileFormat.xlWorkbookNormal, 
        Type.Missing,
        Type.Missing, 
        false, 
        false, 
        XlSaveAsAccessMode.xlNoChange,
        Type.Missing, 
        Type.Missing, 
        Type.Missing, 
        Type.Missing, 
        Type.Missing );

then the application gets a COMException saying

'C:\//temp/00-04.20.18-24-07-2014/' cannot be accessed. The file may be corrupted,        
located on a server that is not responding, or read-only.

This is a pain since I really need to be saving in .xls format, not .xlsx. Any ideas why this exception occurs for SaveAs()?

It would be helpful if you included what's in `SavePath`. 'C:\//temp/00-04.20.18-24-07-2014/' doesn't look like a real file path to me, with one backslash and two slashes after the C:. — Doug Glancy, Jul 24 '14 at 15:42
Yes it made me suspicious too, Doug. But the path is, according to the debugger "C:/temp/00-04..." (and the SaveCopyAs() method puts the file in exactly the right place with exactly the same path). — Julian Gold, Jul 24 '14 at 15:49

score 2 · Accepted Answer · edited May 23 '17 at 12:11

It's kinda obvious what went wrong here. That's not a valid path of course, // should only ever appear as the lead characters for a path to name the machine that contains the file system.

You'll have to de-tune the "Windows works like Unix" expectation when you work with Microsoft application software. Forward slashes in a path are not a problem when you make direct operating system calls. Windows supports them well, not in the least because Windows NT once supported Posix out of the box. The same is not true for other apps, particularly the kind whose source-code base is 25 years old. But is not limited to just old code, VS has problems too. Microsoft treats these kind of bugs reports a bit like Jeff Atwood treats pluralization bugs.

The proper path separator character without any surprises is a backslash.

Thanks Hans. Laughably, I had done a "savePath.Replace('\\', '/')" to try to get around the problem (no change, obviously). It's bizarre how it worked with SaveAsCopy() though! — Julian Gold, Jul 25 '14 at 07:33

Excel interop - saving my newly created spreadsheet throws an exception

1 Answers1