if (deleteOldFile)
        {
            if (System.IO.File.Exists(outputPath)) { System.IO.File.Delete(outputPath); }
        }
        // Create the Excel Application object
        ApplicationClass excelApp = new ApplicationClass();

        // Create a new Excel Workbook
        Workbook excelWorkbook = excelApp.Workbooks.Add(Type.Missing);

        int sheetIndex = 0;

        // Copy each DataTable
        foreach (System.Data.DataTable dt in dataSet.Tables)
        {

            // Copy the DataTable to an object array
            object[,] rawData = new object[dt.Rows.Count + 1, dt.Columns.Count];

            // Copy the column names to the first row of the object array
            for (int col = 0; col < dt.Columns.Count; col++)
            {
                rawData[0, col] = dt.Columns[col].ColumnName;
            }

            // Copy the values to the object array
            for (int col = 0; col < dt.Columns.Count; col++)
            {
                for (int row = 0; row < dt.Rows.Count; row++)
                {
                    rawData[row + 1, col] = dt.Rows[row].ItemArray[col];
                }
            }

            // Calculate the final column letter
            string finalColLetter = string.Empty;
            string colCharset = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
            int colCharsetLen = colCharset.Length;

            if (dt.Columns.Count > colCharsetLen)
            {
                finalColLetter = colCharset.Substring(
                    (dt.Columns.Count - 1) / colCharsetLen - 1, 1);
            }

            finalColLetter += colCharset.Substring(
                    (dt.Columns.Count - 1) % colCharsetLen, 1);

            // Create a new Sheet
            Worksheet excelSheet = (Worksheet)excelWorkbook.Sheets.Add(
                excelWorkbook.Sheets.get_Item(++sheetIndex),
                Type.Missing, 1, XlSheetType.xlWorksheet);

            excelSheet.Name = dt.TableName;

            // Fast data export to Excel
            string excelRange = string.Format("A1:{0}{1}",
                finalColLetter, dt.Rows.Count + 1);

            excelSheet.get_Range(excelRange, Type.Missing).Value2 = rawData;

            // Mark the first row as BOLD
            ((Range)excelSheet.Rows[1, Type.Missing]).Font.Bold = true;
        }
        //excelApp.Application.AlertBeforeOverwriting = false;
        excelApp.Application.DisplayAlerts = false;
        // Save and Close the Workbook
        excelWorkbook.SaveAs(outputPath, XlFileFormat.xlWorkbookNormal, Type.Missing,
            Type.Missing, Type.Missing, Type.Missing, XlSaveAsAccessMode.xlExclusive,
            Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing);
        excelWorkbook.Close(true, Type.Missing, Type.Missing);
        excelWorkbook = null;

        // Release the Application object
        excelApp.Quit();
        excelApp = null;

        // Collect the unreferenced objects
        GC.Collect();
        GC.WaitForPendingFinalizers();