DataTable数据导入Excel(导入到三个工作表)

 Microsoft.Office.Interop.Excel.ApplicationClass xlApp = new Microsoft.Office.Interop.Excel.ApplicationClass();            #region 新建一个Excel            if (sheetName == "PaymentDetail")//第二次进入时不需要创建Excel             {                xlApp.DefaultFilePath = ConfigurationSettings.AppSettings["ExcelFilesDriver"].ToString();                 xlApp.DisplayAlerts = true;                xlApp.SheetsInNewWorkbook = 1;                Microsoft.Office.Interop.Excel.Workbook xlBook = xlApp.Workbooks.Add(true);                xlBook.SaveCopyAs("PaymentExport-" + Yok.Components.YokContext.Current.CurrentUser.CompanyID.ToString() + "-" + DateTime.Now.ToString("yyyy-MM-dd") + ".xls");            }             #endregion            string filePath = xlApp.DefaultFilePath + "PaymentExport-" + Yok.Components.YokContext.Current.CurrentUser.CompanyID.ToString() + "-" + DateTime.Now.ToString("yyyy-MM-dd") + ".xls";            object oMissing = System.Reflection.Missing.Value;            xlApp.Visible = false;            xlApp.DisplayAlerts = false;            Microsoft.Office.Interop.Excel.Workbooks oBooks = xlApp.Workbooks;            Microsoft.Office.Interop.Excel._Workbook xlWorkbook = null;            xlWorkbook = oBooks.Open(filePath,oMissing,oMissing,oMissing,oMissing,oMissing,oMissing,            oMissing,oMissing,oMissing,oMissing,oMissing,oMissing,oMissing,oMissing);            Microsoft.Office.Interop.Excel.Worksheet xlWorksheet;            // 添加入一个新的Sheet页。            xlWorksheet = (Microsoft.Office.Interop.Excel.Worksheet)xlWorkbook.Worksheets.Add(oMissing,oMissing,1,oMissing);            //新加的Sheet页名。            xlWorksheet.Name = sheetName;            #region 导入数据到Excel            //将DataTable的列名导入Excel表第一行            int rowNum = dt.Rows.Count;            int columnNum = dt.Columns.Count;            int rowIndex = 1;            int columnIndex = 0;            foreach (DataColumn dc in dt.Columns)            {                columnIndex++;                xlApp.Cells[rowIndex, columnIndex] = dc.ColumnName;            }            //将DataTable中的数据导入Excel中            for (int i = 0; i < rowNum; i++)            {                rowIndex++;                columnIndex = 0;                for (int j = 0; j < columnNum; j++)                {                    columnIndex++;                    xlApp.Cells[rowIndex, columnIndex] = dt.Rows[i][j].ToString();                }            }            #endregion              // 保存并关闭这个工作簿。            xlWorkbook.Close(Microsoft.Office.Interop.Excel.XlSaveAction.xlSaveChanges, oMissing, oMissing);            System.Runtime.InteropServices.Marshal.ReleaseComObject(xlWorkbook);            xlWorkbook = null;            //结束进程，释放资源            xlApp.Quit();            GC.Collect();             #region 输出IO并提供下载            if (sheetName == "PaymentApprovalDetail")//只有运行第二遍时才打印输出            {                                this.btnDeleteTable.Visible = true;                FileInfo Fi = new FileInfo(filePath);                if (Fi.Exists)                {                    FileStream fs = new FileStream(filePath, FileMode.Open);                    byte[] bytes = new byte[(int)fs.Length];                    fs.Read(bytes, 0, bytes.Length);                    fs.Close();                    Response.Charset = "GBK";                    Response.ContentType = "application/octet-stream";                    Response.AddHeader("Content-Disposition", "attachment; filename=PaymentExport"+ DateTime.Now.ToString("yyyy-MM-dd") + ".xls");                    Response.BinaryWrite(bytes);                    Response.Flush();                    Response.End();               }               }            #endregion