这里使用的NPOI版本为: 2.1.3.1

官方下载地址: http://npoi.codeplex.com/releases

版本内包含.Net 2.0 与.Net 4.0

.Net 4.0中包含文件

使用时需引用需要引用所有5个dll

使用到的引用

using NPOI.HSSF.UserModel;

using NPOI.SS.UserModel;

using NPOI.XSSF.UserModel;

还有经过自己整理的导入导出Excel代码：

        /// <summary>

        /// Excel导入成Datable

        /// </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)

        {

            DataTable dt = new DataTable();

            IWorkbook workbook;

            string fileExt = Path.GetExtension(file).ToLower();

            using (FileStream fs = new FileStream(file, FileMode.Open, FileAccess.Read))

            {

                //XSSFWorkbook 适用XLSX格式，HSSFWorkbook 适用XLS格式

                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(0);

                //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;

        }

        /// <summary>

        /// Datable导出成Excel

        /// </summary>

        /// <param name="dt"></param>

        /// <param name="file">导出路径(包括文件名与扩展名)</param>

        public static void TableToExcel(DataTable dt, string file)

        {

            IWorkbook workbook;

            string fileExt = Path.GetExtension(file).ToLower();

            if (fileExt == ".xlsx") { workbook = new XSSFWorkbook(); } else if (fileExt == ".xls") { workbook = new HSSFWorkbook(); } else { workbook = null; }

            if (workbook == null) { return; }

            ISheet sheet = string.IsNullOrEmpty(dt.TableName) ? workbook.CreateSheet("Sheet1") : workbook.CreateSheet(dt.TableName);

            //表头

            IRow row = sheet.CreateRow(0);

            for (int i = 0; i < dt.Columns.Count; i++)

            {

                ICell cell = row.CreateCell(i);

                cell.SetCellValue(dt.Columns[i].ColumnName);

            }

            //数据

            for (int i = 0; i < dt.Rows.Count; i++)

            {

                IRow row1 = sheet.CreateRow(i + 1);

                for (int j = 0; j < dt.Columns.Count; j++)

                {

                    ICell cell = row1.CreateCell(j);

                    cell.SetCellValue(dt.Rows[i][j].ToString());

                }

            }

            //转为字节数组

            MemoryStream stream = new MemoryStream();

            workbook.Write(stream);

            var buf = stream.ToArray();

            //保存为Excel文件

            using (FileStream fs = new FileStream(file, FileMode.Create, FileAccess.Write))

            {

                fs.Write(buf, 0, buf.Length);

                fs.Flush();

            }

        }

        /// <summary>

        /// 获取单元格类型

        /// </summary>

        /// <param name="cell"></param>

        /// <returns></returns>

        private static object GetValueType(ICell cell)

        {

            if (cell == null)

                return null;

            switch (cell.CellType)

            {

                case CellType.Blank: //BLANK:

                    return null;

                case CellType.Boolean: //BOOLEAN:

                    return cell.BooleanCellValue;

                case CellType.Numeric: //NUMERIC:

                    return cell.NumericCellValue;

                case CellType.String: //STRING:

                    return cell.StringCellValue;

                case CellType.Error: //ERROR:

                    return cell.ErrorCellValue;

                case CellType.Formula: //FORMULA:

                default:

                    return "=" + cell.CellFormula;

            }

        }