Crystal Reports - Export to excel (formatted output)

I am using ReportDocument object with following options to export rpt data to excel

crystalExportOptions = (ExportOptions)reportDocument.ExportOptions;

                    if (oFileType.IsExcel)
                    {
                        DiskFileDestinationOptions diskOptions = new DiskFileDestinationOptions();
                        diskOptions.DiskFileName = destinationFolder + sExportFileName;

                        ExcelFormatOptions formatOptions = new ExcelFormatOptions();
                        formatOptions.ExcelTabHasColumnHeadings = true;
                        formatOptions.ShowGridLines = true;
                        formatOptions.ExcelUseConstantColumnWidth = true;
                        formatOptions.ExcelConstantColumnWidth = 1000;
                        crystalExportOptions.ExportFormatOptions = formatOptions;
                        crystalExportOptions.ExportFormatType = ExportFormatType.ExcelRecord;
                        crystalExportOptions.ExportDestinationType = ExportDestinationType.DiskFile;
                        crystalExportOptions.ExportDestinationOptions = diskOptions;
                    }

using (Stream stream = reportDocument.ExportToStream(ExportFormatType.Excel))
{
      using (MemoryStream memoryStream = new MemoryStream())
                        {

                            stream.CopyTo(memoryStream);
                           //Save to DB
                        }
                    }
}

when I retrieve from db and download the excel it looks unformatted. How to make the cells Autowidth for the column in the excel file?

Thanks for your help