private void btnExportReport_Click(object sender, RoutedEventArgs e)
        {
            // Create report
            ReportsBLL.calculateReport(Convert.ToInt32(this.lbReportYear.Content));

            // Insert data into excel sheet
            using (ExcelPackage p = new ExcelPackage())
            {
                // Here setting some document properties
                p.Workbook.Properties.Author = "YM";
                p.Workbook.Properties.Title  = "Sales Monthly Report";

                // Create a sheet
                p.Workbook.Worksheets.Add("WorkSheet");
                ExcelWorksheet ws = p.Workbook.Worksheets[1];


                // Write to excel sheet 1
                // sheet 1 table 1 = s1t1, sheet 1 table 2 = s1t2, sheet 1 table 3 = s1t3
                int currentRow = 1;
                currentRow = writeToExcel("s1t1", currentRow, ws, "");
                currentRow = writeToExcel("s1t2", currentRow, ws, "");
                writeToExcel("s1t3", currentRow, ws, "");
                // Write to excel sheet 2
                currentRow = 1;
                p.Workbook.Worksheets.Add("WorkSheet2");
                ExcelWorksheet ws2 = p.Workbook.Worksheets[2];
                p.Workbook.Worksheets.Add("WorkSheet3");
                ExcelWorksheet ws3 = p.Workbook.Worksheets[3];
                DataTable      dt  = SalesBLL.getSalesAll();
                if (dt.Rows.Count != 0)
                {
                    foreach (DataRow dr in dt.Rows)
                    {
                        currentRow = writeToExcel("s2", currentRow, ws2, dr["Id"].ToString());
                    }
                    // Write s2 Total
                    writeToExcel("s2", currentRow + 2, ws2, "");

                    currentRow = 1;
                    foreach (DataRow dr in dt.Rows)
                    {
                        currentRow = writeToExcel("s3", currentRow, ws3, dr["Id"].ToString());
                    }
                    // Write s3 Total
                    writeToExcel("s3", currentRow + 2, ws3, "");
                }

                // Generate A File with Random name
                Byte[] bin = p.GetAsByteArray();
                //string file = "d:\\" + Guid.NewGuid().ToString() + ".xlsx";
                string savePath = saveFile();
                string file     = savePath;
                File.WriteAllBytes(file, bin);
                System.Windows.Forms.MessageBox.Show("檔案儲存完畢", "Message");
            }
        }