C# 使用NPOI dll在excel导出中添加货币格式-不工作-为什么？ IDataFormat dataFormatCustom = sheet.Workbook.CreateDataFormat(); ICellStyle

使用NPOI dll在excel导出中添加货币格式-不工作-为什么？

        IDataFormat dataFormatCustom = sheet.Workbook.CreateDataFormat();

        ICellStyle dateStyle = sheet.Workbook.CreateCellStyle(); //date
        dateStyle.DataFormat = dataFormatCustom.GetFormat("dd/mm/yyyy hh:mm");

        ICellStyle amountStyle = sheet.Workbook.CreateCellStyle(); //money
        amountStyle.DataFormat = dataFormatCustom.GetFormat("$#,##0.00");

        ICellStyle percentagesStyle = sheet.Workbook.CreateCellStyle(); //אחוז - עשרוני
        percentagesStyle.DataFormat = dataFormatCustom.GetFormat("0.00\"%\"");           

        ICellStyle numberStyle = sheet.Workbook.CreateCellStyle(); //אחוז - עשרוני
        numberStyle.DataFormat = dataFormatCustom.GetFormat("#,##0");
////
///
 switch (typeFormat)
            {
              case 5://date
                newCell.CellStyle = dateStyle;
                break;
              case 2: //Money
                if (val != 0)
                {
                  newCell.SetCellType(CellType.Numeric);
                  newCell.CellStyle.DataFormat = amountStyle.DataFormat;
                  newCell.SetCellValue(val);
                }
                break;
              case 3: //Percentage:
                if (val != 0)
                {
                  newCell.SetCellType(CellType.Numeric);
                  newCell.CellStyle.DataFormat = percentagesStyle.DataFormat;
                  newCell.SetCellValue(val);
                }
                break;
            }