NPOI Helper文档

    public class ExcelHelper
    {
        /// <summary>
        /// NPOI Excel转DataTable
        /// </summary>
        /// <param name="excelServerPath"></param>
        /// <returns></returns>
        public static DataTable ExcelToDataTable(string excelServerPath, bool hasTitle = true)
        {
            FileStream fs = System.IO.File.OpenRead(excelServerPath);
            IWorkbook workBook = WorkbookFactory.Create(fs, ImportOption.All);

            ISheet sheet = workBook.GetSheetAt(0);
            DataTable dt = null;
            if (hasTitle)
            {
                dt = SheetToDataTableHasTitle(sheet);
            }
            else
            {
                dt = SheetToDataTable(sheet);
            }
            fs.Close();
            fs.Dispose();
            workBook.Close();
            return dt;
        }

        /// <summary>
        /// NPOI Excel转DataTable
        /// </summary>
        /// <param name="excelServerPath"></param>
        /// <returns></returns>
        public static DataTable ExcelToDataTable(Stream stream)
        {
            IWorkbook workBook = WorkbookFactory.Create(stream, ImportOption.All);

            ISheet sheet = workBook.GetSheetAt(0);
            DataTable dt = SheetToDataTable(sheet);

            workBook.Close();
            return dt;
        }

        /// <summary>
        /// NPOI Excel转DataSet
        /// </summary>
        /// <param name="excelServerPath"></param>
        /// <returns></returns>
        public static DataSet ExcelToDataSet(string excelServerPath, bool hasTitle = true)
        {
            FileStream fs = System.IO.File.OpenRead(excelServerPath);
            IWorkbook workBook = WorkbookFactory.Create(fs, ImportOption.All);
            fs.Close();
            fs.Dispose();

            DataSet ds = new DataSet();
            for (int i = 0; i < workBook.NumberOfSheets; i++)
            {
                ISheet sheet = workBook.GetSheetAt(i);
                DataTable dt = null;
                if (hasTitle)
                {
                    dt = SheetToDataTableHasTitle(sheet);
                }
                else
                {
                    dt = SheetToDataTable(sheet);
                }
                ds.Tables.Add(dt);
            }
            return ds;
        }

        /// <summary>
        /// NPOI DataTable转Excel
        /// </summary>
        /// <param name="dt"></param>
        /// <param name="fileName"></param>
        /// <param name="contentEncode"></param>
        public static void Export(DataTable dt, string fileName, Dictionary<int, List<string>> dic = null)
        {
            if (dt == null || dt.Columns.Count <= 0)
            {
                return;
            }
            IWorkbook workBook = new HSSFWorkbook();
            DataTableFillWorkBook(dt, workBook, dic);
            Export(workBook, fileName);
        }

        /// <summary>
        /// NPOI DataSet转Excel
        /// </summary>
        public static void Export(DataSet ds, string fileName, Dictionary<int, Dictionary<int, List<string>>> dic = null)
        {
            if (ds == null || ds.Tables.Count <= 0)
            {
                return;
            }
            IWorkbook workBook = new HSSFWorkbook();
            for (int i = 0; i < ds.Tables.Count; i++)
            {
                var dt = ds.Tables[i];
                Dictionary<int, List<string>> itemDic = null;
                if (dic != null && dic.ContainsKey(i))
                {
                    itemDic = dic[i];
                }
                DataTableFillWorkBook(dt, workBook, itemDic);
            }
            Export(workBook, fileName);
        }

        /// <summary>
        /// 根据DataTable导出csv文件
        /// </summary>
        /// <param name="dataTable">DataTable数据</param>
        /// <param name="fileName">文件名（不带后缀）</param>
        /// <param name="encodeName">编码方式 如 utf-8</param>
        /// <param name="isCloseHttpResponse">是否关闭HttpResponse</param>
        public static void ExportCsv(DataTable dataTable, string fileName, string encodeName, bool isCloseHttpResponse)
        {
            HttpResponse httpResponse = HttpContext.Current.Response;

            if (null == dataTable)
            {
                return;
            }

            StringBuilder strBuilder = new StringBuilder();

            //组合信息
            int columnCount = dataTable.Columns.Count;

            for (int i = 0; i < columnCount; i++)
            {
                string colName = dataTable.Columns[i].ColumnName + "";
                if (colName.Contains(","))
                {
                    colName = colName.Replace(",", "，");
                }

                if (i == columnCount - 1)
                {
                    strBuilder.Append(colName + "
");
                }
                else
                {
                    strBuilder.Append(colName + ",");
                }
            }

            foreach (DataRow row in dataTable.Rows)
            {
                for (int i = 0; i < columnCount; i++)
                {
                    string rowValue = row[i].ToString() + "";
                    if (rowValue.Contains(","))
                    {
                        rowValue = rowValue.Replace(",", "，");
                    }

                    //如果是行尾
                    if (i == columnCount - 1)
                    {
                        strBuilder.Append(rowValue + "
");
                    }
                    else
                    {
                        strBuilder.Append(rowValue + ",");
                    }
                }
            }

            #region 客户端导出文件

            //内容编码格式设定
            Encoding contentEncode = Encoding.GetEncoding(encodeName);
            httpResponse.AppendHeader("Content-Disposition", "attachment;filename=" + fileName + ".csv");
            httpResponse.ContentEncoding = contentEncode;
            httpResponse.ContentType = ".csv";

            httpResponse.Clear();
            httpResponse.Write(strBuilder.ToString());
            httpResponse.End();

            #endregion
        }

        /// <summary>
        /// 根据DataTable导出csv文件
        /// </summary>
        /// <param name="csvServerPath">csv路径</param>
        public static DataTable CsvToDataTable(string csvServerPath)
        {
            Regex reg = new Regex("","");

            int intColCount = 0;
            DataTable dt = new DataTable("myTableName");

            string columnLine;
            string[] columnsArray;

            using (StreamReader streamReader = new StreamReader(csvServerPath, System.Text.Encoding.Default))
            {
                columnLine = streamReader.ReadLine();
                columnsArray = columnLine.Split(',');

                intColCount = columnsArray.Length;
                for (int i = 0; i < columnsArray.Length; i++)
                {
                    DataColumn mydc = new DataColumn(columnsArray[i].Replace(""", ""), typeof(string));
                    dt.Columns.Add(mydc);
                }

                while ((columnLine = streamReader.ReadLine()) != null)
                {
                    columnsArray = columnLine.Split(',');

                    DataRow mydr = dt.NewRow();
                    for (int i = 0; i < intColCount; i++)
                    {
                        mydr[i] = columnsArray[i].Replace(""", "");
                    }

                    dt.Rows.Add(mydr);
                }
            }

            return dt;
        }

        /// <summary>
        /// 导出EXCEL
        /// </summary>
        /// <param name="strContent">html</param>
        /// <param name="fileName"></param>
        /// <param name="contentEncode"></param>
        public static void HtmlExcel(string strContent, string fileName, Encoding contentEncode)
        {
            ExportExcel(strContent, fileName, contentEncode);
        }

        /// <summary>
        /// 导出Excel
        /// </summary>
        /// <param name="strContent">内容</param>
        /// <param name="fileName">文件名称</param>
        /// <param name="contentEncode">内容编码</param>
        private static void ExportExcel(string strContent, string fileName, Encoding contentEncode)
        {
            StringBuilder strBuilder = new StringBuilder();
            strBuilder.Append("<html xmlns="http://www.w3.org/1999/xhtml" xmlns:x="urn:schemas-microsoft-com:office:excel">");
            strBuilder.Append("<head>");
            strBuilder.Append("<xml>");
            strBuilder.Append("<x:ExcelWorkbook>");
            strBuilder.Append("<x:ExcelWorksheets>");
            strBuilder.Append("<x:ExcelWorksheet>");
            strBuilder.Append("<x:Name>Sheet1</x:Name>");
            strBuilder.Append("<x:WorksheetOptions>");
            strBuilder.Append("<x:Print>");
            strBuilder.Append("<x:ValidPrinterInfo/>");
            strBuilder.Append("</x:Print>");
            strBuilder.Append("</x:WorksheetOptions>");
            strBuilder.Append("</x:ExcelWorksheet>");
            strBuilder.Append("</x:ExcelWorksheets>");
            strBuilder.Append("</x:ExcelWorkbook>");
            strBuilder.Append("</xml>");
            strBuilder.Append("</head>");
            strBuilder.Append("<body><table>");
            strBuilder.Append(strContent);
            strBuilder.Append("</table></body>");
            strBuilder.Append("</html>");

            #region 客户端导出文件

            HttpResponse httpResponse = HttpContext.Current.Response;

            httpResponse.AddHeader("Pragma", "public");
            httpResponse.AddHeader("Cache-Control", "max-age=0");
            httpResponse.AddHeader("content-disposition", "attachment;filename=" + fileName + ".xls");
            httpResponse.ContentEncoding = contentEncode;
            httpResponse.ContentType = "application/vnd.ms-excel";

            httpResponse.Clear();
            httpResponse.Write(strBuilder.ToString());
            httpResponse.End();

            #endregion
        }

        /// <summary>
        /// 输出Excel
        /// </summary>
        /// <param name="workBook"></param>
        /// <param name="fileName"></param>
        /// <param name="contentEncode"></param>
        public static void Export(IWorkbook workBook, string fileName)
        {
            MemoryStream ms = new MemoryStream();
            workBook.Write(ms);
            HttpResponse httpResponse = HttpContext.Current.Response;
            httpResponse.AddHeader("Pragma", "public");
            httpResponse.AddHeader("Cache-Control", "max-age=0");
            String userAgent = HttpContext.Current.Request.UserAgent;
            //IE
            if (userAgent.ToUpper().IndexOf("MSIE") > 0)
            {
                fileName = HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8);
            }
            httpResponse.AddHeader("Content-Disposition", "attachment;filename=" + fileName);
            //httpResponse.AddHeader("content-type", "application/x-msdownload");
            //httpResponse.ContentEncoding = Encoding.UTF8;
            httpResponse.ContentType = "application/vnd.ms-excel";
            httpResponse.BinaryWrite(ms.ToArray());
            workBook = null;
            ms.Close();
            ms.Dispose();
        }

        /// <summary>
        /// 构造Excel下拉
        /// </summary>
        /// <param name="sheet"></param>
        /// <param name="dic"></param>
        public static void StructWorkbookDropdown(ISheet sheet, Dictionary<int, List<string>> dic = null)
        {
            foreach (var item in dic.Keys)
            {
                if (dic[item] != null && dic[item].Count > 0)
                {
                    CellRangeAddressList regions = new CellRangeAddressList(1, 65535, item, item);
                    DVConstraint constraint = DVConstraint.CreateExplicitListConstraint(dic[item].ToArray());
                    HSSFDataValidation dataValidate = new HSSFDataValidation(regions, constraint);
                    sheet.AddValidationData(dataValidate);
                }
            }
        }

        /// <summary>
        /// 清空单元格内容
        /// </summary>
        public static void RemoveSheetContent(ISheet sheet, bool isRemoveRow, CellRangeAddress address)
        {
            for (int i = address.FirstRow; i <= address.LastRow; i++)
            {
                //移除全部合并
                for (int n = sheet.NumMergedRegions - 1; n >= 0; n--)
                {
                    sheet.RemoveMergedRegion(n);
                }

                IRow row = sheet.GetRow(i);
                if (row == null)
                {
                    continue;
                }
                if (isRemoveRow == true)
                {
                    sheet.RemoveRow(row);
                    continue;
                }
                for (int c = address.FirstColumn; c <= address.LastColumn; c++)
                {
                    ICell cell = row.GetCell(c);
                    if (cell == null)
                    {
                        continue;
                    }
                    cell.SetCellValue("");
                }
            }
        }

        #region 私有方法

        /// <summary>
        /// NPOI Sheet转Datatable
        /// </summary>
        /// <param name="sheet"></param>
        /// <returns></returns>
        private static DataTable SheetToDataTable(ISheet sheet)
        {
            if (sheet.LastRowNum <= 0)
            {
                return null;
            }

            DataTable dt = new DataTable(sheet.SheetName);

            int maxColumnCount = 0;
            for (int i = 0; i <= sheet.LastRowNum; i++)
            {
                IRow row = sheet.GetRow(i);
                if (row == null || row.LastCellNum <= maxColumnCount)
                {
                    continue;
                }
                maxColumnCount = row.LastCellNum;
            }

            for (int i = 0; i < maxColumnCount; i++)
            {
                dt.Columns.Add();
            }

            for (int i = 0; i <= sheet.LastRowNum; i++)
            {
                DataRow dataRow = dt.NewRow();
                IRow row = sheet.GetRow(i);
                if (row == null)
                {
                    continue;
                }
                for (int j = 0; j < row.LastCellNum; j++)
                {
                    ICell cell = row.GetCell(j);
                    if (cell == null)
                    {
                        dataRow[j] = "";
                        continue;
                    }

                    switch (cell.CellType)
                    {
                        case CellType.Boolean:
                            dataRow[j] = cell.BooleanCellValue;
                            break;
                        case CellType.Numeric:
                            dataRow[j] = cell.NumericCellValue;
                            break;
                        case CellType.String:
                            dataRow[j] = cell.StringCellValue;
                            break;
                        default:
                            dataRow[j] = cell.ToString();
                            break;
                    }
                }
                dt.Rows.Add(dataRow);
            }
            return dt;
        }

        private static DataTable SheetToDataTableHasTitle(ISheet sheet)
        {
            DataTable dt = new DataTable();
            if (!string.IsNullOrWhiteSpace(sheet.SheetName))
            {
                dt.TableName = sheet.SheetName;
            }
            IRow firstRow = sheet.GetRow(0);
            for (int i = 0; i < firstRow.Cells.Count; i++)
            {
                ICell cell = firstRow.GetCell(i);
                if (cell != null)
                {
                    var colName = firstRow.GetCell(i).ToString();
                    colName = Regex.Replace(colName, @"s", "");
                    if (dt.Columns[colName] == null)
                    {
                        dt.Columns.Add(colName);
                    }
                    else
                    {
                        dt.Columns.Add();
                    }
                }
                else
                {
                    dt.Columns.Add();
                }
            }
            for (int i = 1; i <= sheet.LastRowNum; i++)
            {
                DataRow dataRow = dt.NewRow();
                IRow row = sheet.GetRow(i);
                if (row == null)
                {
                    continue;
                }
                for (int j = 0; j < firstRow.LastCellNum; j++)
                {
                    ICell cell = row.GetCell(j);
                    if (cell == null)
                    {
                        dataRow[j] = "";
                        continue;
                    }

                    switch (cell.CellType)
                    {
                        case CellType.Boolean:
                            dataRow[j] = cell.BooleanCellValue;
                            break;
                        case CellType.Numeric:
                            dataRow[j] = cell.NumericCellValue;
                            break;
                        case CellType.String:
                            dataRow[j] = cell.StringCellValue;
                            break;
                        default:
                            dataRow[j] = cell.ToString();
                            break;
                    }
                }
                dt.Rows.Add(dataRow);
            }

            return dt;
        }

        /// <summary>
        /// 导出Excel数据填充
        /// </summary>
        /// <param name="dt"></param>
        /// <param name="workBook"></param>
        private static void DataTableFillWorkBook(DataTable dt, IWorkbook workBook, Dictionary<int, List<string>> dic = null)
        {
            var sheetName = dt.TableName;
            if (string.IsNullOrWhiteSpace(sheetName))
            {
                sheetName = string.Format("sheet{0}", workBook.NumberOfSheets + 1);
            }
            ISheet sheet = workBook.CreateSheet(sheetName);

            if (dic != null && dic.Count > 0)
            {
                foreach (var item in dic.Keys)
                {
                    if (dic[item] != null && dic[item].Count > 0)
                    {
                        CellRangeAddressList regions = new CellRangeAddressList(1, 65535, item, item);
                        DVConstraint constraint = DVConstraint.CreateExplicitListConstraint(dic[item].ToArray());
                        HSSFDataValidation dataValidate = new HSSFDataValidation(regions, constraint);
                        sheet.AddValidationData(dataValidate);
                    }
                }
            }

            IRow firstRow = sheet.CreateRow(0);
            for (int i = 0; i < dt.Columns.Count; i++)
            {
                firstRow.CreateCell(i, CellType.String).SetCellValue(dt.Columns[i].ColumnName);
            }
            for (int i = 0; i < dt.Rows.Count; i++)
            {
                IRow row = sheet.CreateRow(i + 1);
                DataRow dtRow = dt.Rows[i];
                for (int j = 0; j < dt.Columns.Count; j++)
                {
                    row.CreateCell(j, CellType.String).SetCellValue(dtRow[j].ToString());
                }
            }
        }

        #endregion

    }

Dictionary<int, string> dicCurrencyType = EnumAttribute.GetEnumDictionary(typeof(CurrencyType));
                Dictionary<string, string> dicIsInsured = new Dictionary<string, string>();
                dicIsInsured.Add("true", "购买");
                dicIsInsured.Add("false", "不购买");

                //读取模版
                string tplFilePath = Server.MapPath("~/Areas/YXExports/Content/Temp/order_lcl_templete.xls");
                FileStream fs = System.IO.File.OpenRead(tplFilePath);
                IWorkbook workBook = WorkbookFactory.Create(fs, ImportOption.All);
                fs.Close();
                fs.Dispose();

       
                ISheet sheet2 = workBook.GetSheetAt(1);
                for (int i = 0; i < productList.Count; i++)
                {
                    IRow row = sheet2.GetRow(i + 1);
                    if (row == null)
                    {
                        row = sheet2.CreateRow(i + 1);
                    }
                    ICell cell = row.GetCell(0);
                    if (cell == null)
                    {
                        cell = row.CreateCell(0);
                    }
                    cell.SetCellValue(productList[i].Name);
                }

     
                for (int i = 0; i < supportCountries.Count; i++)
                {
                    IRow row = sheet2.GetRow(i + 1);
                    if (row == null)
                    {
                        row = sheet2.CreateRow(i + 1);
                    }
                    ICell cell = row.GetCell(1);
                    if (cell == null)
                    {
                        cell = row.CreateCell(1);
                    }
                    cell.SetCellValue(supportCountries[i].CnGeoName);
                }

                //下拉框
                ISheet sheet1 = workBook.GetSheetAt(0);
                Dictionary<int, List<string>> dropDown = new Dictionary<int, List<string>>();
                dropDown.Add(1, productList.Select(l => l.Name).ToList()); 
                dropDown.Add(23, dicCurrencyType.Select(l => l.Key.ToString()).ToList()); 
                dropDown.Add(24, dicIsInsured.Select(l => l.Value.ToString()).ToList()); 
                ExcelHelper.StructWorkbookDropdown(sheet1, dropDown);

                ExcelHelper.Export(workBook, string.Format(" {0}.xls", DateTime.Now.ToString("yyyyMMddHHmmss")));

导出excel

   DataTable dt = new DataTable();
                dt.Columns.Add("公司名称");
                dt.Columns.Add("客户邮箱");
              
               
                foreach (var item in list)
                {
                    DataRow dr = dt.NewRow();
                    dr["公司名称"] = item.CompanyName;
                    dr["客户邮箱"] = item.Email;
                   

                    dt.Rows.Add(dr);

                }
                string fileName = string.Format("客户列表.xls");
                ExcelHelper.Export(dt, fileName);