基于NPOI导出和导入Excel

概述

　　NPOI，顾名思义，就是POI的.NET版本。NPOI就是用.NET语言编写的一套数据导出Excel的开源项目，支持XML、xls、xlsx、ppt等格式。.NET不仅实现Excel导出还可以实现Excel导入，读取Excel的数据。

实现

　　1、通过nuget，添加NPOI组件1.2以上对应的DLL文件；

　　2、编写如下Nopi封装类，该类实现如下功能点

　　　　1> 该类实现数据的超过65535自动分写下一个sheet；

　　　　2> 该类实现Web数据导出和文件保存到本地；

　　　　3> 该类实现Excel文件的读取导出；

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.IO;
using System.Text;
using NPOI;
using NPOI.HPSF;
using NPOI.HSSF;
using NPOI.HSSF.UserModel;
using NPOI.HSSF.Util;
using NPOI.POIFS;
using NPOI.Util;
using System.Data;
using NPOI.SS.UserModel;
using NPOI.SS.Util;

namespace DBI.Web.Common
{
    public class NpoiHelper
    {
        /// <summary>
        /// DataTable导出到Excel文件
        /// </summary>
        /// <param name="dtSource">源DataTable</param>
        /// <param name="strHeaderText">表头文本</param>
        /// <param name="strFileName">保存位置</param>
        public static void Export(DataTable dtSource, string strHeaderText, string strFileName)
        {
            using (MemoryStream ms = Export(dtSource, strHeaderText))
            {
                using (FileStream fs = new FileStream(strFileName, FileMode.Create, FileAccess.Write))
                {
                    byte[] data = ms.ToArray();
                    fs.Write(data, , data.Length);
                    fs.Flush();
                }
            }
        }

        /// <summary>
        /// DataTable导出到Excel的MemoryStream，带标题和表头
        /// </summary>
        /// <param name="dtSource">源DataTable</param>
        /// <param name="strHeaderText">表头文本</param>
        public static MemoryStream Export(DataTable dtSource, string strHeaderText)
        {
            HSSFWorkbook workbook = new HSSFWorkbook();
            ISheet sheet = workbook.CreateSheet(string.IsNullOrWhiteSpace(dtSource.TableName) ? "Sheet1" : dtSource.TableName); 

            #region 右击文件 属性信息            

            DocumentSummaryInformation dsi = PropertySetFactory.CreateDocumentSummaryInformation();
            dsi.Company = "NPOI";
            workbook.DocumentSummaryInformation = dsi;

            SummaryInformation si = PropertySetFactory.CreateSummaryInformation();
            si.Author = "TCL"; //填加xls文件作者信息
            si.ApplicationName = "创建程序信息"; //填加xls文件创建程序信息
            si.LastAuthor = "最后保存者信息"; //填加xls文件最后保存者信息
            si.Comments = "作者信息"; //填加xls文件作者信息
            si.Title = "标题信息"; //填加xls文件标题信息

            si.Subject = "主题信息";//填加文件主题信息
            si.CreateDateTime = DateTime.Now;
            workbook.SummaryInformation = si;    

            #endregion

            #region 取得列宽,调整宽度  有待优化，如果数据很多，这个地方就会很耗时

            int[] arrColWidth = new int[dtSource.Columns.Count];
            foreach (DataColumn item in dtSource.Columns)
            {
                arrColWidth[item.Ordinal] = Encoding.GetEncoding().GetBytes(item.ColumnName.ToString()).Length;
            }

            for (int i = ; i < dtSource.Rows.Count; i++)
            {
                for (int j = ; j < dtSource.Columns.Count; j++)
                {
                    int intTemp = Encoding.GetEncoding().GetBytes(dtSource.Rows[i][j].ToString()).Length;
                    if (intTemp > arrColWidth[j])
                    {
                        arrColWidth[j] = intTemp;
                    }
                }
            }

            #endregion

            var dateStyle = workbook.CreateCellStyle();
            var format = workbook.CreateDataFormat();
            dateStyle.DataFormat = format.GetFormat("yyyy-mm-dd");

            var DataCellStyle = CreateBasicCellStyle(workbook);

            //计算行数，由于Excel 2003最大条数是65535,超过65535自动创建下一个sheet
            int rowIndex = ;
            foreach (DataRow row in dtSource.Rows)
            {
                #region 新建表，填充表头，填充列头，样式
                if (rowIndex ==  || rowIndex == )
                {
                    if (rowIndex != )
                    {
                        sheet = workbook.CreateSheet();
                    }

                    #region 表头及样式
                    {
                        var headerRow = sheet.CreateRow();
                        headerRow.HeightInPoints = ;
                        headerRow.CreateCell().SetCellValue(strHeaderText);

                        ICellStyle headStyle = workbook.CreateCellStyle();
                        headStyle.Alignment = HorizontalAlignment.Center;
                        headStyle.VerticalAlignment = VerticalAlignment.Center;// 上下居中
                        headStyle.FillForegroundColor = (short); // 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）
                        IFont font = workbook.CreateFont();
                        font.FontHeightInPoints = ;
                        font.Boldweight = ;
                        headStyle.SetFont(font);
                        headerRow.GetCell().CellStyle = headStyle;
                        //合并单元格
                        sheet.AddMergedRegion(new CellRangeAddress(, , , dtSource.Columns.Count - ));
                    }
                    #endregion

                    #region 列头及样式
                    {
                        IRow headerRow = sheet.CreateRow();
                        ICellStyle headStyle = workbook.CreateCellStyle();
                        headStyle.Alignment = HorizontalAlignment.Center;
                        headStyle.VerticalAlignment = VerticalAlignment.Center;
                        //定义字体
                        IFont font = workbook.CreateFont();
                        font.FontHeightInPoints = ;
                        font.Boldweight = ;
                        headStyle.SetFont(font);
                        foreach (DataColumn column in dtSource.Columns)
                        {
                            headerRow.CreateCell(column.Ordinal).SetCellValue(column.ColumnName);
                            headerRow.GetCell(column.Ordinal).CellStyle = headStyle;

                            //设置列宽
                            sheet.SetColumnWidth(column.Ordinal, (arrColWidth[column.Ordinal] + ) * );
                        }
                    }
                    #endregion

                    rowIndex = ;
                }
                #endregion

                #region 填充内容
                IRow dataRow = sheet.CreateRow(rowIndex);
                foreach (DataColumn column in dtSource.Columns)
                {
                    ICell newCell = dataRow.CreateCell(column.Ordinal);
                    newCell.CellStyle = DataCellStyle;

                    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++;
            }
            using (MemoryStream ms = new MemoryStream())
            {
                workbook.Write(ms);
                ms.Flush();
                ms.Position = ;
                return ms;
            }
        }

        /// <summary>
        /// 用于Web导出
        /// </summary>
        /// <param name="dtSource">源DataTable</param>
        /// <param name="strHeaderText">表头文本</param>
        /// <param name="strFileName">文件名</param>
        public static void ExportByWeb(DataTable dtSource, string strHeaderText, string strFileName)
        {
            HttpContext curContext = HttpContext.Current;

            // 设置编码和附件格式
            curContext.Response.ContentType = "application/vnd.ms-excel";
            curContext.Response.ContentEncoding = Encoding.UTF8;
            curContext.Response.Charset = "";
            curContext.Response.AppendHeader("Content-Disposition",
                "attachment;filename=" + HttpUtility.UrlEncode(strFileName, Encoding.UTF8));

            curContext.Response.BinaryWrite(Export(dtSource, strHeaderText).GetBuffer());
            curContext.Response.End();
        }

        /// <summary>读取excel
        /// 默认第一行为标头,Exel导出Table数据
        /// </summary>
        /// <param name="strFileName">excel文档路径</param>
        /// <returns></returns>
        public static DataTable Import(string strFileName)
        {
            DataTable dt = new DataTable();

            HSSFWorkbook hssfworkbook;
            using (FileStream file = new FileStream(strFileName, FileMode.Open, FileAccess.Read))
            {
                hssfworkbook = new HSSFWorkbook(file);
            }
            ISheet sheet = hssfworkbook.GetSheetAt();
            System.Collections.IEnumerator rows = sheet.GetRowEnumerator();

            IRow headerRow = sheet.GetRow();
            int cellCount = headerRow.LastCellNum;

            for (int j = ; j < cellCount; j++)
            {
                ICell cell = headerRow.GetCell(j);
                dt.Columns.Add(cell.ToString());
            }

            for (int i = (sheet.FirstRowNum + ); i <= sheet.LastRowNum; i++)
            {
                IRow row = sheet.GetRow(i);
                DataRow dataRow = dt.NewRow();

                for (int j = row.FirstCellNum; j < cellCount; j++)
                {
                    if (row.GetCell(j) != null)
                        dataRow[j] = row.GetCell(j).ToString();
                }

                dt.Rows.Add(dataRow);
            }
            return dt;
        }

        private static HSSFCellStyle CreateBasicCellStyle(HSSFWorkbook workbook)
        {
            var cellStyle = workbook.CreateCellStyle() as HSSFCellStyle;
            cellStyle.BorderLeft = BorderStyle.Thin;
            cellStyle.BorderRight = BorderStyle.Thin;
            cellStyle.BorderTop = BorderStyle.Thin;
            cellStyle.BorderBottom = BorderStyle.Thin;
            cellStyle.Alignment = HorizontalAlignment.Center;
            cellStyle.VerticalAlignment = VerticalAlignment.Center;
            return cellStyle;
        }
    }
}

参考文档

　　NPOI导出Excel表功能实现(多个工作簿)http://www.cnblogs.com/zhengjuzhuan/archive/2010/02/01/1661103.html

　　NET使用NPOI组件将数据导出Excel-通用方法  http://www.tuicool.com/articles/eq6FRb

　  NET NPOI导出Excel详解    http://www.cnblogs.com/yinrq/p/5590970.html

　　基于NPOI的自定义样式报表引擎——ExcelReport　　http://www.cnblogs.com/hanzhaoxin/p/4232572.html