.NET NPOI导出Excel详解

NPOI，顾名思义，就是POI的.NET版本。那POI又是什么呢？POI是一套用Java写成的库，能够帮助开发者在没有安装微软Office的情况下读写Office的文件。

支持的文件格式包括xls, doc, ppt等。

官方网站：http://npoi.codeplex.com/

nuget直接获取使用

一、NPOI生成Excel

            //创建工作薄

            var workbook = new HSSFWorkbook();

            //创建表

            var table = workbook.CreateSheet("joye.net");

            //模拟20行20列数据

            for (var i = ; i < ; i++)

            {

                var row = table.CreateRow(i);

                for (int j = ; j < ; j++)

                {

                    var cell = row.CreateCell(j);

                    cell.SetCellValue(j);

                }

            }

            //打开xls文件，如没有则创建，如存在则在创建是不要打开该文件

            using (var fs = File.OpenWrite(@"c:/joye.net.xls"))

            {

                workbook.Write(fs);   //向打开的这个xls文件中写入mySheet表并保存。

                Console.WriteLine("生成成功");

            }

二、NPOI读取Excel

using (var fs = File.OpenRead(@"c:/joye.net.xls"))

            {

                //把xls文件中的数据写入workbook1中

                var workbook1 = new HSSFWorkbook(fs);

                for (var i = ; i < workbook1.NumberOfSheets; i++)

                {

                    var sheet = workbook1.GetSheetAt(i);

                    for (var j = ; j <= sheet.LastRowNum; j++)

                    {

                        //读取当前行数据

                        var row = sheet.GetRow(j);

                        if (row != null)

                        {

                            for (var k = ; k <= row.LastCellNum; k++)

                            {   //当前表格

                                var cell = row.GetCell(k);

                                if (cell != null)

                                {

                                    Console.Write(cell.ToString() + "  ");

                                }

                            }

                        }

                        Console.WriteLine();

                    }

                }

            }

读出的结果

三、简单学习

/// <summary>

        ///  组装workbook.

        /// </summary>

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

        /// <param name="columnHeader">表头</param>

        /// <returns></returns>

        public static HSSFWorkbook BuildWorkbook1(DataTable dt, string columnHeader = "")

        {

            var workbook = new HSSFWorkbook();

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

            #region 文件属性信息

            {

                var dsi = PropertySetFactory.CreateDocumentSummaryInformation();

                dsi.Company = "NPOI";

                workbook.DocumentSummaryInformation = dsi;

                SummaryInformation si = PropertySetFactory.CreateSummaryInformation();

                si.Author = "文件作者信息";

                si.ApplicationName = "创建程序信息";

                si.LastAuthor = "最后保存者信息";

                si.Comments = "作者信息";

                si.Title = "标题信息";

                si.Subject = "主题信息";

                si.CreateDateTime = DateTime.Now;

                workbook.SummaryInformation = si;

            }

            #endregion

            var dateStyle = workbook.CreateCellStyle();

            var format = workbook.CreateDataFormat();

            dateStyle.DataFormat = format.GetFormat("yyyy-mm-dd");

            //取得列宽

            var arrColWidth = new int[dt.Columns.Count];

            foreach (DataColumn item in dt.Columns)

            {

                arrColWidth[item.Ordinal] = Encoding.GetEncoding().GetBytes(item.ColumnName.ToString()).Length;

            }

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

            {

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

                {

                    int intTemp = Encoding.GetEncoding().GetBytes(dt.Rows[i][j].ToString()).Length;

                    if (intTemp > arrColWidth[j])

                    {

                        arrColWidth[j] = intTemp;

                    }

                }

            }

            int rowIndex = ;

            foreach (DataRow row in dt.Rows)

            {

                #region 表头 列头

                if (rowIndex ==  || rowIndex == )

                {

                    if (rowIndex != )

                    {

                        sheet = workbook.CreateSheet();

                    }

                    #region 表头及样式

                    {

                        var headerRow = sheet.CreateRow();

                        headerRow.HeightInPoints = ;

                        headerRow.CreateCell().SetCellValue(columnHeader);

                        //CellStyle

                        ICellStyle headStyle = workbook.CreateCellStyle();

                        headStyle.Alignment = HorizontalAlignment.Center;// 左右居中

                        headStyle.VerticalAlignment = VerticalAlignment.Center;// 上下居中

                        // 设置单元格的背景颜色（单元格的样式会覆盖列或行的样式）

                        headStyle.FillForegroundColor = (short);

                        //定义font

                        IFont font = workbook.CreateFont();

                        font.FontHeightInPoints = ;

                        font.Boldweight = ;

                        headStyle.SetFont(font);

                        headerRow.GetCell().CellStyle = headStyle;

                        sheet.AddMergedRegion(new CellRangeAddress(, , , dt.Columns.Count - ));

                    }

                    #endregion

                    #region 列头及样式

                    {

                        var headerRow = sheet.CreateRow();

                        //CellStyle

                        ICellStyle headStyle = workbook.CreateCellStyle();

                        headStyle.Alignment = HorizontalAlignment.Center;// 左右居中

                        headStyle.VerticalAlignment = VerticalAlignment.Center;// 上下居中

                        //定义font

                        IFont font = workbook.CreateFont();

                        font.FontHeightInPoints = ;

                        font.Boldweight = ;

                        headStyle.SetFont(font);

                        foreach (DataColumn column in dt.Columns)

                        {

                            headerRow.CreateCell(column.Ordinal).SetCellValue(column.ColumnName);

                            headerRow.GetCell(column.Ordinal).CellStyle = headStyle;

                            sheet.SetColumnWidth(column.Ordinal, (arrColWidth[column.Ordinal] + ) * );

                        }

                    }

                    #endregion

                    if (columnHeader != "")

                    {

                        //header row

                        IRow row0 = sheet.CreateRow();

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

                        {

                            ICell cell = row0.CreateCell(i, CellType.String);

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

                        }

                    }

                    rowIndex = ;

                }

                #endregion

                #region 内容

                var dataRow = sheet.CreateRow(rowIndex);

                foreach (DataColumn column in dt.Columns)

                {

                    var newCell = dataRow.CreateCell(column.Ordinal);

                    string drValue = row[column].ToString();

                    switch (column.DataType.ToString())

                    {

                        case "System.String"://字符串类型

                            newCell.SetCellValue(drValue);

                            break;

                        case "System.DateTime"://日期类型

                            DateTime dateV;

                            DateTime.TryParse(drValue, out dateV);

                            newCell.SetCellValue(dateV);

                            newCell.CellStyle = dateStyle;//格式化显示

                            break;

                        case "System.Boolean"://布尔型

                            bool boolV = false;

                            bool.TryParse(drValue, out boolV);

                            newCell.SetCellValue(boolV);

                            break;

                        case "System.Int16"://整型

                        case "System.Int32":

                        case "System.Int64":

                        case "System.Byte":

                            int intV = ;

                            int.TryParse(drValue, out intV);

                            newCell.SetCellValue(intV);

                            break;

                        case "System.Decimal"://浮点型

                        case "System.Double":

                            double doubV = ;

                            double.TryParse(drValue, out doubV);

                            newCell.SetCellValue(doubV);

                            break;

                        case "System.DBNull"://空值处理

                            newCell.SetCellValue("");

                            break;

                        default:

                            newCell.SetCellValue("");

                            break;

                    }

                }

                #endregion

                rowIndex++;

            }

            //自动列宽

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

                sheet.AutoSizeColumn(i, true);

            return workbook;

        }

学习代码

            var dt = new DataTable();

             //模拟20行20列数据

            for (var i = ; i < ; i++)

            {

                dt.Columns.Add(i.ToString());

            }

            for (var j = ; j < ; j++)

            {

                dt.Rows.Add(new object[] {  ,, });

            }

            var newBook = BuildWorkbook(dt);

            using (var fs = File.OpenWrite(@"c:/joye.net1.xls"))

            {

                newBook.Write(fs);

                Console.WriteLine("生成成功");

            }

代码调用

四、NPOI导出Excel 65536问题

        public static HSSFWorkbook BuildWorkbook(DataTable dt)

        {

            var book = new HSSFWorkbook();  

            ISheet sheet = book.CreateSheet("Sheet1");

            //Data Rows

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

            {

                IRow drow = sheet.CreateRow(i);

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

                {

                    ICell cell = drow.CreateCell(j, CellType.String);

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

                }

            }

            //自动列宽

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

                sheet.AutoSizeColumn(i, true);

            return book;

        }

NPOI导出Excel超过65536会报异常，原来是由于NPOI这个动态库导致的，然后看了下版本，发现是1.2.5。然后百度了下，发现这个版本的NPOI只支持office2003，二office2003最多支持65536行

解决方式：

1、只是在插入数据的时候，加个判断，如果数据条数大于65536时，就在创建一个sheet

        //65536判断处理

        public static HSSFWorkbook BuildWorkbook(DataTable dt)

        {

            var book = new HSSFWorkbook();

            ISheet sheet1 = book.CreateSheet("Sheet1");

            ISheet sheet2 = book.CreateSheet("Sheet2");

            //填充数据

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

            {

                if (i < )

                {

                    IRow drow = sheet1.CreateRow(i);

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

                    {

                        ICell cell = drow.CreateCell(j, CellType.String);

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

                    }

                }

                if (i >= )

                {

                    IRow drow = sheet2.CreateRow(i - );

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

                    {

                        ICell cell = drow.CreateCell(j, CellType.String);

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

                    }

                }

            }

            //自动列宽

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

            {

                sheet1.AutoSizeColumn(i, true);

                sheet2.AutoSizeColumn(i, true);

            }

            return book;

        }

2、考虑使用高版本Office，使用用对象支持高版本的NPOI

        //高版本

        public static XSSFWorkbook BuildWorkbook(DataTable dt)

        {

            var book = new XSSFWorkbook();

            ISheet sheet = book.CreateSheet("Sheet1");

            //Data Rows

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

            {

                IRow drow = sheet.CreateRow(i);

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

                {

                    ICell cell = drow.CreateCell(j, CellType.String);

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

                }

            }

            //自动列宽

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

                sheet.AutoSizeColumn(i, true);

            return book;

        }

五、web开发中导出Excel

        public static void ExportExcel(DataTable dt, string fileName = "")

        {

            //生成Excel

            IWorkbook book = BuildWorkbook(dt);

            //web 下载

            if (fileName == "")

                fileName = string.Format("{0:yyyyMMddHHmmssffff}", DateTime.Now);

            fileName = fileName.Trim();

            string ext = Path.GetExtension(fileName);

            if (ext.ToLower() == ".xls" || ext.ToLower() == ".xlsx")

                fileName = fileName.Replace(ext, string.Empty);

            HttpResponse httpResponse = HttpContext.Current.Response;

            httpResponse.Clear();

            httpResponse.Buffer = true;

            httpResponse.Charset = Encoding.UTF8.BodyName;

            httpResponse.AppendHeader("Content-Disposition", "attachment;filename=" + fileName + ".xls");

            httpResponse.ContentEncoding = Encoding.UTF8;

            httpResponse.ContentType = "application/vnd.ms-excel; charset=UTF-8";

            book.Write(httpResponse.OutputStream);

            httpResponse.End();

        }

using NPOI.HSSF.UserModel;

using NPOI.SS.UserModel;

using NPOI.XSSF.UserModel;

using System;

using System.Collections;

using System.Collections.Generic;

using System.Data;

using System.Reflection;

using System.Text;

using System.Linq;

namespace Gto.Report.Contract

{

    public static class ExcelHelperForCs

    {

        /// <summary>

        ///  组装workbook.

        /// </summary>

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

        /// <param name="columnHeader">表头</param>

        /// <returns></returns>

        public static HSSFWorkbook BuildWorkbook1(DataTable dt, string columnHeader = "")

        {

            var workbook = new HSSFWorkbook();

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

            var dateStyle = workbook.CreateCellStyle();

            var format = workbook.CreateDataFormat();

            dateStyle.DataFormat = format.GetFormat("yyyy-mm-dd");

            //取得列宽

            var arrColWidth = new int[dt.Columns.Count];

            foreach (DataColumn item in dt.Columns)

            {

                arrColWidth[item.Ordinal] = Encoding.GetEncoding().GetBytes(item.ColumnName.ToString()).Length;

            }

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

            {

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

                {

                    int intTemp = Encoding.GetEncoding().GetBytes(dt.Rows[i][j].ToString()).Length;

                    if (intTemp > arrColWidth[j])

                    {

                        arrColWidth[j] = intTemp;

                    }

                }

            }

            int rowIndex = ;

            foreach (DataRow row in dt.Rows)

            {

                #region 表头 列头

                if (rowIndex ==  || rowIndex == )

                {

                    if (rowIndex != )

                    {

                        sheet = workbook.CreateSheet();

                    }

                    #region 表头及样式

                    {

                        var headerRow = sheet.CreateRow();

                        headerRow.HeightInPoints = ;

                        headerRow.CreateCell().SetCellValue(columnHeader);

                        //CellStyle

                        ICellStyle headStyle = workbook.CreateCellStyle();

                        headStyle.Alignment = NPOI.SS.UserModel.HorizontalAlignment.Center;// 左右居中

                        headStyle.VerticalAlignment = VerticalAlignment.Center;// 上下居中

                        // 设置单元格的背景颜色（单元格的样式会覆盖列或行的样式）

                        headStyle.FillForegroundColor = (short);

                        //定义font

                        IFont font = workbook.CreateFont();

                        font.FontHeightInPoints = ;

                        font.Boldweight = ;

                        headStyle.SetFont(font);

                        headerRow.GetCell().CellStyle = headStyle;

                        sheet.AddMergedRegion(new NPOI.SS.Util.CellRangeAddress(, , , dt.Columns.Count - ));

                    }

                    #endregion

                    #region 列头及样式

                    {

                        var headerRow = sheet.CreateRow();

                        //CellStyle

                        ICellStyle headStyle = workbook.CreateCellStyle();

                        headStyle.Alignment = NPOI.SS.UserModel.HorizontalAlignment.Center;// 左右居中

                        headStyle.VerticalAlignment = VerticalAlignment.Center;// 上下居中

                        //定义font

                        IFont font = workbook.CreateFont();

                        font.FontHeightInPoints = ;

                        font.Boldweight = ;

                        headStyle.SetFont(font);

                        foreach (DataColumn column in dt.Columns)

                        {

                            headerRow.CreateCell(column.Ordinal).SetCellValue(column.ColumnName);

                            headerRow.GetCell(column.Ordinal).CellStyle = headStyle;

                            sheet.SetColumnWidth(column.Ordinal, (arrColWidth[column.Ordinal] + ) * );

                        }

                    }

                    #endregion

                    if (columnHeader != "")

                    {

                        //header row

                        IRow row0 = sheet.CreateRow();

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

                        {

                            ICell cell = row0.CreateCell(i, CellType.String);

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

                        }

                    }

                    rowIndex = ;

                }

                #endregion

                #region 内容

                var dataRow = sheet.CreateRow(rowIndex);

                foreach (DataColumn column in dt.Columns)

                {

                    var newCell = dataRow.CreateCell(column.Ordinal);

                    string drValue = row[column].ToString();

                    switch (column.DataType.ToString())

                    {

                        case "System.String"://字符串类型

                            newCell.SetCellValue(drValue);

                            break;

                        case "System.DateTime"://日期类型

                            DateTime dateV;

                            DateTime.TryParse(drValue, out dateV);

                            newCell.SetCellValue(dateV);

                            newCell.CellStyle = dateStyle;//格式化显示

                            break;

                        case "System.Boolean"://布尔型

                            bool boolV = false;

                            bool.TryParse(drValue, out boolV);

                            newCell.SetCellValue(boolV);

                            break;

                        case "System.Int16"://整型

                        case "System.Int32":

                        case "System.Int64":

                        case "System.Byte":

                            int intV = ;

                            int.TryParse(drValue, out intV);

                            newCell.SetCellValue(intV);

                            break;

                        case "System.Decimal"://浮点型

                        case "System.Double":

                            double doubV = ;

                            double.TryParse(drValue, out doubV);

                            newCell.SetCellValue(doubV);

                            break;

                        case "System.DBNull"://空值处理

                            newCell.SetCellValue("");

                            break;

                        default:

                            newCell.SetCellValue("");

                            break;

                    }

                }

                #endregion

                rowIndex++;

            }

            //自动列宽

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

                sheet.AutoSizeColumn(i, true);

            return workbook;

        }

        public static DataTable ToDataTable<T>(IList<T> items)

        {

            var tb = new DataTable(typeof(T).Name);

            PropertyInfo[] props = typeof(T).GetProperties(BindingFlags.Public | BindingFlags.Instance);

            foreach (PropertyInfo prop in props)

            {

                Type t = GetCoreType(prop.PropertyType);

                tb.Columns.Add(prop.Name, t);

            }

            foreach (T item in items)

            {

                var values = new object[props.Length];

                for (int i = ; i < props.Length; i++)

                {

                    values[i] = props[i].GetValue(item, null);

                }

                tb.Rows.Add(values);

            }

            return tb;

        }

        public static bool IsNullable(Type t)

        {

            return !t.IsValueType || (t.IsGenericType && t.GetGenericTypeDefinition() == typeof(Nullable<>));

        }

        public static Type GetCoreType(Type t)

        {

            if (t != null && IsNullable(t))

            {

                if (!t.IsValueType)

                {

                    return t;

                }

                else

                {

                    return Nullable.GetUnderlyingType(t);

                }

            }

            else

            {

                return t;

            }

        }

        /// <summary>

        /// DataTable导出Excel2007（.xlsx）

        /// </summary>

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

        /// <param name="file">文件路径（.xlsx）</param>

        /// <param name="sheetname">Excel工作表名</param>

        public static void TableToExcelForXLSX2007(DataTable dt, string file, string sheetname)

        {

            XSSFWorkbook xssfworkbook = new XSSFWorkbook();//建立Excel2007对象

            ISheet sheet = xssfworkbook.CreateSheet(sheetname);//新建一个名称为sheetname的工作簿

            //设置基本样式

            ICellStyle style = xssfworkbook.CreateCellStyle();

            style.WrapText = true;

            IFont font = xssfworkbook.CreateFont();

            font.FontHeightInPoints = ;

            font.FontName = "Arial";

            style.SetFont(font);

            //设置统计样式

            ICellStyle style1 = xssfworkbook.CreateCellStyle();

            style1.WrapText = true;

            IFont font1 = xssfworkbook.CreateFont();

            font1.FontHeightInPoints = ;

            font1.Boldweight = (short)NPOI.SS.UserModel.FontBoldWeight.Bold;

            font1.FontName = "Arial";

            style1.SetFont(font1);

            //设置大类样式

            ICellStyle style2 = xssfworkbook.CreateCellStyle();

            style2.WrapText = true;

            //style2.FillBackgroundColor = NPOI.HSSF.Util.HSSFColor.Gold.Index;

            //style2.FillPattern = FillPattern.SolidForeground;

            IFont font2 = xssfworkbook.CreateFont();

            font2.FontHeightInPoints = ;

            font2.Boldweight = (short)NPOI.SS.UserModel.FontBoldWeight.Bold;

            font2.FontName = "Arial";

            style2.SetFont(font2);

            //设置列名

            IRow row = sheet.CreateRow();

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

            {

                ICell cell = row.CreateCell(i);

                var rowName = dt.Columns[i].ColumnName;

                string rowRealName = "";

                switch (rowName)

                {

                    case "IncomeType":

                        rowRealName = "交易类型";

                        break;

                    case "CreateDate":

                        rowRealName = "发生日期";

                        break;

                    case "ChangeAmount":

                        rowRealName = "合计金额";

                        break;

                    case "SubsectionName":

                        rowRealName = "分段名称";

                        break;

                    case "CorporateName":

                        rowRealName = "公司名称";

                        break;

                    case "Province":

                        rowRealName = "省份";

                        break;

                    case "ShuntName":

                        rowRealName = "项目";

                        break;

                    case "CountAmount":

                        rowRealName = "本年累计金额";

                        break;

                    default:

                        rowRealName = "";

                        break;

                }

                cell.SetCellValue(rowRealName);

                cell.CellStyle = style;

            }

            int paymentRowIndex = ;

            //单元格赋值

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

            {

                IRow row1 = sheet.CreateRow(i + );

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

                {

                    ICell cell = row1.CreateCell(j);

                    if (dt.Rows[i][j].ToString().Contains("小计") || dt.Rows[i][j].ToString().Contains("流量净额"))

                    {

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

                        cell.CellStyle = style2;

                    }

                    else if (dt.Rows[i][j].ToString().Contains("一") || dt.Rows[i][j].ToString().Contains("二") || dt.Rows[i][j].ToString().Contains("三"))

                    {

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

                        cell.CellStyle = style1;

                    }

                    else

                    {

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

                        cell.CellStyle = style;

                    }

                }

                paymentRowIndex++;

            }

            //列宽自适应，只对英文和数字有效

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

            {

                sheet.AutoSizeColumn(i);

            }

            //获取当前列的宽度，然后对比本列的长度，取最大值

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

            {

                int columnWidth = sheet.GetColumnWidth(columnNum) / ;

                for (int rowNum = ; rowNum <= sheet.LastRowNum; rowNum++)

                {

                    IRow currentRow;

                    //当前行未被使用过

                    if (sheet.GetRow(rowNum) == null)

                    {

                        currentRow = sheet.CreateRow(rowNum);

                    }

                    else

                    {

                        currentRow = sheet.GetRow(rowNum);

                    }

                    if (currentRow.GetCell(columnNum) != null)

                    {

                        ICell currentCell = currentRow.GetCell(columnNum);

                        int length = Encoding.Default.GetBytes(currentCell.ToString()).Length;

                        if (columnWidth < length)

                        {

                            columnWidth = length;

                        }

                    }

                }

                sheet.SetColumnWidth(columnNum, columnWidth * );

            }

            using (System.IO.Stream stream = System.IO.File.OpenWrite(file))

            {

                //写入文件

                xssfworkbook.Write(stream);

                stream.Close();

            }

        }

        /// <summary>

        /// DataTable导出Excel2003（.xls）

        /// </summary>

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

        /// <param name="file">文件路径（.xls）</param>

        /// <param name="sheetname">Excel工作表名</param>

        public static void TableToExcelForXLSX2003(DataTable dt, string file, string sheetname)

        {

            HSSFWorkbook xssfworkbook = new HSSFWorkbook();//建立Excel2003对象

            HSSFSheet sheet = (HSSFSheet)xssfworkbook.CreateSheet(sheetname);//新建一个名称为sheetname的工作簿

            //设置基本样式

            ICellStyle style = xssfworkbook.CreateCellStyle();

            style.WrapText = true;

            IFont font = xssfworkbook.CreateFont();

            font.FontHeightInPoints = ;

            font.FontName = "Arial";

            style.SetFont(font);

            //设置统计样式

            ICellStyle style1 = xssfworkbook.CreateCellStyle();

            style1.WrapText = true;

            IFont font1 = xssfworkbook.CreateFont();

            font1.FontHeightInPoints = ;

            font1.Boldweight = (short)NPOI.SS.UserModel.FontBoldWeight.Bold;

            font1.FontName = "Arial";

            style1.SetFont(font1);

            //设置大类样式

            ICellStyle style2 = xssfworkbook.CreateCellStyle();

            style2.WrapText = true;

            //style2.FillBackgroundColor = NPOI.HSSF.Util.HSSFColor.Gold.Index;

            //style2.FillPattern = FillPattern.SolidForeground;

            IFont font2 = xssfworkbook.CreateFont();

            font2.FontHeightInPoints = ;

            font2.Boldweight = (short)NPOI.SS.UserModel.FontBoldWeight.Bold;

            font2.FontName = "Arial";

            style2.SetFont(font2);

            //设置列名

            HSSFRow row = (HSSFRow)sheet.CreateRow();

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

            {

                ICell cell = (ICell)row.CreateCell(i);

                var rowName = dt.Columns[i].ColumnName;

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

                string rowRealName = "";

                switch (rowName)

                {

                    case "IncomeType":

                        rowRealName = "交易类型";

                        break;

                    case "CreateDate":

                        rowRealName = "发生日期";

                        break;

                    case "ChangeAmount":

                        rowRealName = "合计金额";

                        break;

                    case "SubsectionName":

                        rowRealName = "分段名称";

                        break;

                    case "CorporateName":

                        rowRealName = "公司名称";

                        break;

                    case "Province":

                        rowRealName = "省份";

                        break;

                    case "ShuntName":

                        rowRealName = "项目";

                        break;

                    case "CountAmount":

                        rowRealName = "本年累计金额";

                        break;

                    default:

                        rowRealName = "";

                        break;

                }

                cell.SetCellValue(rowRealName);

                cell.CellStyle = style;

            }

            int paymentRowIndex = ;

            //单元格赋值

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

            {

                IRow row1 = sheet.CreateRow(i + );

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

                {

                    ICell cell = row1.CreateCell(j);

                    if (dt.Rows[i][j].ToString().Contains("小计") || dt.Rows[i][j].ToString().Contains("流量净额"))

                    {

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

                        cell.CellStyle = style2;

                    }

                    else if (dt.Rows[i][j].ToString().Contains("一") || dt.Rows[i][j].ToString().Contains("二") || dt.Rows[i][j].ToString().Contains("三"))

                    {

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

                        cell.CellStyle = style1;

                    }

                    else

                    {

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

                        cell.CellStyle = style;

                    }

                }

                paymentRowIndex++;

            }

            //列宽自适应，只对英文和数字有效

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

            {

                sheet.AutoSizeColumn(i);

            }

            //获取当前列的宽度，然后对比本列的长度，取最大值

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

            {

                int columnWidth = sheet.GetColumnWidth(columnNum) / ;

                for (int rowNum = ; rowNum <= sheet.LastRowNum; rowNum++)

                {

                    IRow currentRow;

                    //当前行未被使用过

                    if (sheet.GetRow(rowNum) == null)

                    {

                        currentRow = sheet.CreateRow(rowNum);

                    }

                    else

                    {

                        currentRow = sheet.GetRow(rowNum);

                    }

                    if (currentRow.GetCell(columnNum) != null)

                    {

                        ICell currentCell = currentRow.GetCell(columnNum);

                        int length = Encoding.Default.GetBytes(currentCell.ToString()).Length;

                        if (columnWidth < length)

                        {

                            columnWidth = length;

                        }

                    }

                }

                sheet.SetColumnWidth(columnNum, columnWidth * );

            }

            using (System.IO.Stream stream = System.IO.File.OpenWrite(file))

            {

                xssfworkbook.Write(stream);

                stream.Close();

            }

        }

    }

}

基于.xls模板生成Excel文件有时间再看

代码下载：https://yunpan.cn/cRBVnTCSchz7k （提取码：779e）

.NET NPOI导出Excel详解的相关教程结束。