NPOI 表格处理

 /// <summary>
        /// 获取单元格类型
        /// </summary>
        /// <param name="cell">目标单元格</param>
        /// <returns></returns>
        private static object GetValueType(ICell cell)
        {
            if (cell == null)
                return null;
            switch (cell.CellType)
            {
                case CellType.Blank:
                    return null;
                case CellType.Boolean:
                    return cell.BooleanCellValue;
                case CellType.Numeric:
                    return cell.NumericCellValue;
                case CellType.String:
                    return cell.StringCellValue;
                case CellType.Error:
                    return cell.ErrorCellValue;
                case CellType.Formula:
                default:
                    return "=" + cell.CellFormula;
            }
        }

        /// <summary>
        /// Excel导入成DataTble
        /// </summary>
        /// <param name="file">导入路径(包含文件名与扩展名)</param>
        /// <returns></returns>
        public static DataTable ExcelToTable(string file ,int pistion=0)
        {
            DataTable dt = new DataTable();
            IWorkbook workbook;
            string fileExt = Path.GetExtension(file).ToLower();
            using (FileStream fs = new FileStream(file, FileMode.Open, FileAccess.Read))
            {
                if (fileExt == ".xlsx") { workbook = new XSSFWorkbook(fs); } else if (fileExt == ".xls") { workbook = new HSSFWorkbook(fs); } else { workbook = null; }
                if (workbook == null) { return null; }
                ISheet sheet = workbook.GetSheetAt(pistion);

                //表头  
                IRow header = sheet.GetRow(sheet.FirstRowNum);
                List<int> columns = new List<int>();
                for (int i = 0; i < header.LastCellNum; i++)
                {
                    object obj = GetValueType(header.GetCell(i));
                    if (obj == null || obj.ToString() == string.Empty)
                    {
                        dt.Columns.Add(new DataColumn("Columns" + i.ToString()));
                    }
                    else
                        dt.Columns.Add(new DataColumn(obj.ToString()));
                    columns.Add(i);
                }
                //数据  
                for (int i = sheet.FirstRowNum + 1; i <= sheet.LastRowNum; i++)
                {
                    DataRow dr = dt.NewRow();
                    bool hasValue = false;
                    foreach (int j in columns)
                    {
                        dr[j] = GetValueType(sheet.GetRow(i).GetCell(j));
                        if (dr[j] != null && dr[j].ToString() != string.Empty)
                        {
                            hasValue = true;
                        }
                    }
                    if (hasValue)
                    {
                        dt.Rows.Add(dr);
                    }
                }
            }
            return dt;
        }

 private static IWorkbook workbook;
        public static int DataTableToExcel(DataTable data, string sheetName, bool isColumnWritten, string fileName)
        {
            int i = 0;
            int j = 0;
            int count = 0;
            ISheet sheet = null;
            if (File.Exists(fileName))
                File.Delete(fileName);
            var fs = new FileStream(fileName, FileMode.OpenOrCreate, FileAccess.ReadWrite);
            if (fileName.IndexOf(".xlsx") > 0)
                workbook = new XSSFWorkbook();
            else if (fileName.IndexOf(".xls") > 0)
                workbook = new HSSFWorkbook();

            try
            {
                if (workbook != null)
                {
                    sheet = workbook.CreateSheet(sheetName);
                }
                else
                {
                    return -1;
                }

                if (isColumnWritten == true)
                {
                    IRow row = sheet.CreateRow(0);
                    for (j = 0; j < data.Columns.Count; ++j)
                    {
                        row.CreateCell(j).SetCellValue(data.Columns[j].ColumnName);
                    }
                    count = 1;
                }
                else
                {
                    count = 0;
                }

                for (i = 0; i < data.Rows.Count; ++i)
                {
                    IRow row = sheet.CreateRow(count);
                    for (j = 0; j < data.Columns.Count; ++j)
                    {
                        row.CreateCell(j).SetCellValue(data.Rows[i][j].ToString());
                    }
                    ++count;
                }
                workbook.Write(fs);
                return count;
            }
            catch (Exception ex)
            {
                Console.WriteLine("Exception: " + ex.Message);
                return -1;
            }
        }

             string worksheetname = string.Empty;
                HSSFWorkbook workbook1 = null;
                using (FileStream stream = File.OpenRead(fazhuSheetFilePath))
                {


                    workbook1 = new HSSFWorkbook(stream);
                }

                int position = 0;
                for (int i = 0; i < workbook1.NumberOfSheets; i++)
                {
                    if (workbook1.GetSheetName(i).Contains("仕様条件編"))//判断Sheet名是否为所需要的
                    {
                        worksheetname = workbook1.GetSheetName(i);//获取worksheet Name  
                        position = i;
                        break;
                    }

                }

               var TaggingTable = ExcelToTable(fazhuSheetFilePath, position);

 

来源：https://www.cnblogs.com/wangcl-8645/p/11961321.html