NPOI新建和读取EXCEL

        //基本NPOI 1.2.5.0
        static void Main(string[] args)
        {
            string path = string.Format("E:\\export{0}.xls", DateTime.Now.ToString("yyyyMMddhhmmss"));

            WriteAExcel(path);
            ReadAExcel(path);
            Console.ReadKey();
        }

        /// <summary>
        /// 创建测试
        /// </summary>
        /// <param name="path">路径</param>
        static void WriteAExcel(string path)
        {
            //创建工作薄
            HSSFWorkbook workbook = new HSSFWorkbook();
            //创建一个名称为"排班表"的表
            ISheet sheet = workbook.CreateSheet("排班表");

            int rowCount = 0;
            int colCount = 6;

            //创建一行, 此行为标题行
            IRow title = sheet.CreateRow(rowCount);
            title.CreateCell(0).SetCellValue(string.Format("{0}({1})", "消化内科", "珠海市人民医院"));

            //合并单元格
            CellRangeAddress cellRangeAddress = new CellRangeAddress(rowCount, rowCount, 0, colCount - 1);
            sheet.AddMergedRegion(cellRangeAddress);
            rowCount++;

            //创建一行, 空行
            sheet.CreateRow(rowCount);
            rowCount++;

            //创建一行，此行为第二行
            IRow headerRow = sheet.CreateRow(rowCount);
            rowCount++;

            //固定区域, 用于header
            sheet.CreateFreezePane(0, 1);

            string[] headerArray = new[] { "医生", "日期", "时间", "预约数", "挂号费", "状态" };

            //表头行
            for (int i = 0; i < headerArray.Length; i++)
            {
                headerRow.CreateCell(i).SetCellValue(headerArray[i]);
            }

            List<MyDataItem> dataList = new List<MyDataItem>();
            #region 测试数据
            dataList.Add(new MyDataItem() { ID = 1, DoctorName = "张某", Date = DateTime.Now, Time = "上午", Place = 3, Fee = 10, Status = "排班" });
            dataList.Add(new MyDataItem() { ID = 2, DoctorName = "李某", Date = DateTime.Now, Time = "下午", Place = 3, Fee = 10, Status = "排班" });
            dataList.Add(new MyDataItem() { ID = 3, DoctorName = "赵某", Date = DateTime.Now, Time = "中午", Place = 3, Fee = 10, Status = "排班" });
            dataList.Add(new MyDataItem() { ID = 4, DoctorName = "杨某", Date = DateTime.Now, Time = "上午", Place = 3, Fee = 10, Status = "停诊" });
            dataList.Add(new MyDataItem() { ID = 5, DoctorName = "黎某", Date = DateTime.Now, Time = "中午", Place = 3, Fee = 10, Status = "排班" });
            dataList.Add(new MyDataItem() { ID = 6, DoctorName = "张某", Date = DateTime.Now, Time = "上午", Place = 3, Fee = 10, Status = "排班" });
            dataList.Add(new MyDataItem() { ID = 7, DoctorName = "李某", Date = DateTime.Now, Time = "下午", Place = 3, Fee = 10, Status = "排班" });
            dataList.Add(new MyDataItem() { ID = 8, DoctorName = "赵某", Date = DateTime.Now, Time = "中午", Place = 3, Fee = 10, Status = "排班" });
            dataList.Add(new MyDataItem() { ID = 9, DoctorName = "杨某", Date = DateTime.Now, Time = "上午", Place = 3, Fee = 10, Status = "停诊" });
            dataList.Add(new MyDataItem() { ID = 10, DoctorName = "黎某", Date = DateTime.Now, Time = "中午", Place = 3, Fee = 10, Status = "排班" });
            dataList.Add(new MyDataItem() { ID = 11, DoctorName = "张某", Date = DateTime.Now, Time = "上午", Place = 3, Fee = 10, Status = "排班" });
            dataList.Add(new MyDataItem() { ID = 12, DoctorName = "李某", Date = DateTime.Now, Time = "下午", Place = 3, Fee = 10, Status = "排班" });
            dataList.Add(new MyDataItem() { ID = 13, DoctorName = "赵某", Date = DateTime.Now, Time = "中午", Place = 3, Fee = 10, Status = "排班" });
            dataList.Add(new MyDataItem() { ID = 14, DoctorName = "杨某", Date = DateTime.Now, Time = "上午", Place = 3, Fee = 10, Status = "停诊" });
            dataList.Add(new MyDataItem() { ID = 15, DoctorName = "黎某", Date = DateTime.Now, Time = "中午", Place = 3, Fee = 10, Status = "排班" });
            dataList.Add(new MyDataItem() { ID = 16, DoctorName = "张某", Date = DateTime.Now, Time = "上午", Place = 3, Fee = 10, Status = "排班" });
            dataList.Add(new MyDataItem() { ID = 17, DoctorName = "李某", Date = DateTime.Now, Time = "下午", Place = 3, Fee = 10, Status = "排班" });
            dataList.Add(new MyDataItem() { ID = 18, DoctorName = "赵某", Date = DateTime.Now, Time = "中午", Place = 3, Fee = 10, Status = "排班" });
            dataList.Add(new MyDataItem() { ID = 19, DoctorName = "杨某", Date = DateTime.Now, Time = "上午", Place = 3, Fee = 10, Status = "停诊" });
            dataList.Add(new MyDataItem() { ID = 20, DoctorName = "黎某", Date = DateTime.Now, Time = "中午", Place = 3, Fee = 10, Status = "排班" });
            #endregion

            //添加下拉选项(序列)
            AddDropdownList1(sheet, rowCount);

            //添加下拉选项(指定数据)
            AddDropdownList2(workbook, sheet, rowCount);

            //插入数据
            for (int i = 0; i < dataList.Count; i++)
            {
                MyDataItem item = dataList[i];
                IRow dataRow = sheet.CreateRow(rowCount);

                dataRow.CreateCell(0).SetCellValue(string.Format("{0}({1})", item.DoctorName, item.ID));
                dataRow.CreateCell(1).SetCellValue(item.Date.ToString("yyyy/MM/dd"));
                dataRow.CreateCell(2).SetCellValue(item.Time);
                dataRow.CreateCell(3).SetCellValue(item.Place);
                dataRow.CreateCell(4).SetCellValue(item.Fee.ToString("N2"));
                dataRow.CreateCell(5);//.SetCellValue(item.Status);
                rowCount++;
            }

            //写入文件
            using (MemoryStream ms = new MemoryStream())
            {
                workbook.Write(ms);

                using (FileStream fs = new FileStream(path, FileMode.Create))
                {
                    byte[] data = ms.ToArray();
                    fs.Write(data, 0, data.Count());
                }
            }
        }

        //读测试
        static void ReadAExcel(string path)
        {
            using (FileStream file = new FileStream(path, FileMode.Open, FileAccess.Read))
            {
                IWorkbook workbook = new HSSFWorkbook(file);
                ISheet sheet = workbook.GetSheet("排班表");
                IRow headerRow = sheet.GetRow(2);

                //一行最后一个方格的编号 即总的列数
                int cellCount = headerRow.LastCellNum;

                //有多少列
                int rowCount = sheet.LastRowNum;

                //读
                for (int i = 2; i < rowCount; i++)
                {
                    IRow row = sheet.GetRow(i);
                    for (int j = row.FirstCellNum; j < cellCount; j++)
                    {
                        Console.Write(" " + row.GetCell(j).ToString());
                    }
                    Console.WriteLine();
                }
            }
        }

        /// <summary>
        /// 添加下拉框(序列)
        /// </summary>
        /// <param name="sheet"></param>
        /// <param name="start"></param>
        static void AddDropdownList1(ISheet sheet, int start)
        {
            CellRangeAddressList regions = new CellRangeAddressList(start, 65535, 5, 5);
            DVConstraint constraint = DVConstraint.CreateExplicitListConstraint(new string[] { "就诊", "停诊" });
            HSSFDataValidation dataValidate = new HSSFDataValidation(regions, constraint);
            sheet.AddValidationData(dataValidate);
        }

        /// <summary>
        /// 添加下拉框(单元格)
        /// </summary>
        /// <param name="workbook"></param>
        /// <param name="sheet"></param>
        /// <param name="start"></param>
        static void AddDropdownList2(HSSFWorkbook workbook, ISheet sheet, int start)
        {
            ISheet sheet2 = workbook.CreateSheet("a");
            sheet2.CreateRow(0).CreateCell(0).SetCellValue("上午");
            sheet2.CreateRow(1).CreateCell(0).SetCellValue("中午");
            sheet2.CreateRow(2).CreateCell(0).SetCellValue("下午");
            sheet2.CreateRow(3).CreateCell(0).SetCellValue("晚上");

            IName range = workbook.CreateName();
            range.RefersToFormula = "a!$A$1:$A$4";
            range.NameName = "timeDic";

            CellRangeAddressList regions = new CellRangeAddressList(start, 65535, 2, 2);
            DVConstraint constraint = DVConstraint.CreateFormulaListConstraint("timeDic");
            HSSFDataValidation dataValidate = new HSSFDataValidation(regions, constraint);
            //添加约束警告
            dataValidate.CreateErrorBox("输入不合法", "请输入下拉列表中的值。");
            sheet.AddValidationData(dataValidate);
        }

        /// <summary>
        /// 测试数据类型
        /// </summary>
        class MyDataItem
        {
            public int ID { get; set; }

            public string DoctorName { get; set; }

            public DateTime Date { get; set; }

            public string Time { get; set; }

            public int Place { get; set; }

            public decimal Fee { get; set; }

            public string Status { get; set; }
        }