New Post: Date vs. Numeric NPOI 2.0.6

if (cell.CellType == CellType.Numeric)
{

 object[targetRowNum, targetColNum] = cell.NumericCellValue.ToString();
 if (DateUtil.IsCellDateFormatted(cell))
 {
     object[targetRowNum, targetColNum] = cell.DateCellValue.ToString("dd-MMM-yyyy");
 }

}

note: you need to use wb = WorkbookFactory.Create(filestream,ImportOption.All); ImportOption.All parameter allows DateUtil.IsCellDateFormatted to work properly.