导入功能实现：var file = HttpContext.Current.Request.Files[0];GetExtensionsFromFileStream(file.InputStream);using NPOI.XSSF.UserModel;public List<MaterialExtend> GetExtensionsFromFileStream(Stream excelFielStream)        {            var list = new List<DBOMS_MaterialExtend>();            var book = new XSSFWorkbook(excelFielStream);            var firstSheet = book.GetSheetAt(0);            var ExtendType = firstSheet.SheetName;            for (int i = 1; i <= firstSheet.LastRowNum; i++)            {                var entity = new DBOMS_MaterialExtend();                XSSFRow row = firstSheet.GetRow(i) as XSSFRow;                entity.MaterialCode = (row.GetCell(0) as XSSFCell).StringCellValue;                entity.ReferFactory = (row.GetCell(1) as XSSFCell).StringCellValue;                entity.ExtendType = (int)Enum.Parse(typeof(ExtendTypeEnum), ExtendType, true);                                list.Add(entity);            }            return list;        }