NPOI在EXCEL中追加数据

DataTable dt = (gridControl1.DataSource as DataTable).Copy(); string tempFile = System.IO.Path.GetTempFileName();  string path = AppConfig.GetValue("ImportResult"); System.IO.FileInfo info = new System.IO.FileInfo(path); info.CopyTo(tempFile, true); XSSFWorkbook workbook = new XSSFWorkbook(tempFile); #region 写入杆塔位置验收对比 ISheet sheet = workbook.GetSheet("杆塔位置验收"); for (int i = 0; i < dt.Rows.Count; i++) {    // 第二步：创建新数据行    NPOI.SS.UserModel.IRow row = sheet.CreateRow(sheet.LastRowNum + 1);    NPOI.SS.UserModel.ICell cell;    // 添加测试数据    cell = row.CreateCell(0);    //cell.CellStyle = cellStyle;    cell.SetCellValue(dt.Rows[i]["塔号"].ToString());    cell = row.CreateCell(1);    //cell.CellStyle = cellStyle;    cell.SetCellValue(dt.Rows[i]["杆塔型式"].ToString());    cell = row.CreateCell(2);    //cell.CellStyle = cellStyle;    cell.SetCellValue(dt.Rows[i]["档距设计值"].ToString());    cell = row.CreateCell(3);    //cell.CellStyle = cellStyle;    cell.SetCellValue(dt.Rows[i]["档距实测值"].ToString());    cell = row.CreateCell(4);    //cell.CellStyle = cellStyle;    cell.SetCellValue(dt.Rows[i]["档距偏差值"].ToString());    cell = row.CreateCell(5);    //cell.CellStyle = cellStyle;    cell.SetCellValue(dt.Rows[i]["档距允许偏差"].ToString());    cell = row.CreateCell(6);    //cell.CellStyle = cellStyle;    cell.SetCellValue(dt.Rows[i]["线路转角设计值"].ToString());    cell = row.CreateCell(7);    //cell.CellStyle = cellStyle;    cell.SetCellValue(dt.Rows[i]["线路转角实测值"].ToString());    cell = row.CreateCell(8);    //cell.CellStyle = cellStyle;    cell.SetCellValue(dt.Rows[i]["线路转角偏差值"].ToString());    cell = row.CreateCell(9);    //cell.CellStyle = cellStyle;    cell.SetCellValue(dt.Rows[i]["线路转角允许偏差"].ToString());    cell = row.CreateCell(10);    //cell.CellStyle = cellStyle;    cell.SetCellValue(dt.Rows[i]["塔位高程设计值"].ToString());    cell = row.CreateCell(11);    //cell.CellStyle = cellStyle;    cell.SetCellValue(dt.Rows[i]["塔位高程实测值"].ToString());    cell = row.CreateCell(12);    //cell.CellStyle = cellStyle;    cell.SetCellValue(dt.Rows[i]["塔位高程偏差值"].ToString());    cell = row.CreateCell(13);    //cell.CellStyle = cellStyle;         cell.SetCellValue(dt.Rows[i]["塔位高程允许偏差"].ToString());     cell = row.CreateCell(14);    //cell.CellStyle = cellStyle;    cell.SetCellValue(dt.Rows[i]["直线桩位置偏移设计值"].ToString());    cell = row.CreateCell(15);    //cell.CellStyle = cellStyle;    cell.SetCellValue(dt.Rows[i]["直线桩位置偏移实测值"].ToString());    cell = row.CreateCell(16);    //cell.CellStyle = cellStyle;    cell.SetCellValue(dt.Rows[i]["直线桩位置偏移偏差值"].ToString());    cell = row.CreateCell(17);    //cell.CellStyle = cellStyle;    cell.SetCellValue(dt.Rows[i]["直线桩位置偏移允许偏差"].ToString());    cell = row.CreateCell(18);    ICellStyle cellStyle = workbook.CreateCellStyle();    if(dt.Rows[i]["是否合格"].ToString()=="合格")        cellStyle.FillForegroundColor = HSSFColor.LIGHT_GREEN.index;    else        cellStyle.FillForegroundColor = HSSFColor.RED.index;    cellStyle.FillPattern = FillPatternType.SOLID_FOREGROUND;    cell.CellStyle = cellStyle;    cell.SetCellValue(dt.Rows[i]["是否合格"].ToString()); } #endregion