使用 NPOI 导出 Excel 文件

【NPOI简介】

NPOI 是 POI 项目的 .NET 版本。POI是一个开源的Java读写Excel、WORD等微软OLE2组件文档的项目。
 
使用 NPOI 你就可以在没有安装 Office 或者相应环境的机器上对 WORD/EXCEL 文档进行读写。NPOI是构建在POI 3.x版本之上的，它可以在没有安装Office的情况下对Word/Excel文档进行读写操作。

NPOI官方教程地址：http://tonyqus.sinaapp.com

googlecode：http://code.google.com/p/npoi/

codeplex：http://npoi.codeplex.com/

Excel 助手类：

using System;
using System.Data;
using System.IO;
using System.Text;
using System.Web;
using NPOI.HPSF;
using NPOI.HSSF.UserModel;
using NPOI.SS.UserModel;
using System.Collections.Generic;
using System.Collections;
namespace Weilog.Core.Document.Excel
{
    /// <summary>
    /// Excel 助手类。
    /// </summary>
    public class ExcelHelper
    {

        private void InitializeWorkbook(HSSFWorkbook hssfworkbook, string headerText)
        {
            hssfworkbook = new HSSFWorkbook();

            //创建一个文档摘要信息实体。
            DocumentSummaryInformation dsi = PropertySetFactory.CreateDocumentSummaryInformation();
            dsi.Company = "Weilog Team"; //公司名称
            hssfworkbook.DocumentSummaryInformation = dsi;

            //创建一个摘要信息实体。
            SummaryInformation si = PropertySetFactory.CreateSummaryInformation();
            si.Subject = "Weilog 系统生成";
            si.Author = "Weilog 系统";
            si.Title = headerText;
            si.Subject = headerText;
            si.CreateDateTime = DateTime.Now;
            hssfworkbook.SummaryInformation = si;

        }

        private static MemoryStream WriteToStream(HSSFWorkbook hssfworkbook)
        {
            //Write the stream data of workbook to the root directory
            MemoryStream file = new MemoryStream();
            hssfworkbook.Write(file);
            return file;
        }
        //Export(DataTable table, string headerText, string sheetName, string[] columnName, string[] columnTitle)
        /// <summary>
        /// 向客户端输出文件。
        /// </summary>
        /// <param name="table">数据表。</param>
        /// <param name="headerText">头部文本。</param>
        /// <param name="sheetName"></param>
        /// <param name="columnName">数据列名称。</param>
        /// <param name="columnTitle">表标题。</param>
        /// <param name="fileName">文件名称。</param>
        public static void Write(DataTable table, string headerText, string sheetName, string[] columnName, string[] columnTitle, string fileName)
        {
            HttpContext context = HttpContext.Current;
            context.Response.ContentType = "application/vnd.ms-excel";
            context.Response.AddHeader("Content-Disposition", string.Format("attachment;filename={0}",HttpUtility.UrlEncode(fileName, Encoding.UTF8)));
            context.Response.Clear();
            HSSFWorkbook hssfworkbook = GenerateData(table, headerText, sheetName, columnName, columnTitle);
            context.Response.BinaryWrite(WriteToStream(hssfworkbook).GetBuffer());
            context.Response.End();
        }
        /// <summary>
        ///
        /// </summary>
        /// <param name="table"></param>
        /// <param name="headerText"></param>
        /// <param name="sheetName"></param>
        /// <param name="columnName"></param>
        /// <param name="columnTitle"></param>
        /// <returns></returns>
        public static HSSFWorkbook GenerateData(DataTable table, string headerText, string sheetName, string[] columnName, string[] columnTitle)
        {
            HSSFWorkbook hssfworkbook = new HSSFWorkbook();
            ISheet sheet = hssfworkbook.CreateSheet(sheetName);

            #region 设置文件属性信息

            //创建一个文档摘要信息实体。
            DocumentSummaryInformation dsi = PropertySetFactory.CreateDocumentSummaryInformation();
            dsi.Company = "Weilog Team"; //公司名称
            hssfworkbook.DocumentSummaryInformation = dsi;

            //创建一个摘要信息实体。
            SummaryInformation si = PropertySetFactory.CreateSummaryInformation();
            si.Subject = "本文档由 Weilog 系统生成";
            si.Author = " Weilog 系统";
            si.Title = headerText;
            si.Subject = headerText;
            si.CreateDateTime = DateTime.Now;
            hssfworkbook.SummaryInformation = si;

            #endregion

            ICellStyle dateStyle = hssfworkbook.CreateCellStyle();
            IDataFormat format = hssfworkbook.CreateDataFormat();
            dateStyle.DataFormat = format.GetFormat("yyyy-mm-dd");

            #region 取得列宽

            int[] colWidth = new int[columnName.Length];
            for (int i = 0; i < columnName.Length; i++)
            {
                colWidth[i] = Encoding.GetEncoding(936).GetBytes(columnTitle[i]).Length;
            }
            for (int i = 0; i < table.Rows.Count; i++)
            {
                for (int j = 0; j < columnName.Length; j++)
                {
                    int intTemp = Encoding.GetEncoding(936).GetBytes(table.Rows[i][columnName[j]].ToString()).Length;
                    if (intTemp > colWidth[j])
                    {
                        colWidth[j] = intTemp;
                    }
                }
            }

            #endregion

            int rowIndex = 0;
            foreach (DataRow row in table.Rows)
            {
                #region 新建表，填充表头，填充列头，样式
                if (rowIndex == 65535 || rowIndex == 0)
                {
                    if (rowIndex != 0)
                    {
                        sheet = hssfworkbook.CreateSheet(sheetName + ((int)rowIndex / 65535).ToString());
                    }

                    #region 表头及样式
                    //if (!string.IsNullOrEmpty(headerText))
                    {
                        IRow headerRow = sheet.CreateRow(0);
                        headerRow.HeightInPoints = 25;
                        headerRow.CreateCell(0).SetCellValue(headerText);

                        ICellStyle headStyle = hssfworkbook.CreateCellStyle();
                        headStyle.Alignment = HorizontalAlignment.CENTER;
                        IFont font = hssfworkbook.CreateFont();
                        font.FontHeightInPoints = 20;
                        font.Boldweight = 700;
                        headStyle.SetFont(font);

                        headerRow.GetCell(0).CellStyle = headStyle;
                        //sheet.AddMergedRegion(new Region(0, 0, 0, dtSource.Columns.Count - 1));
                        sheet.AddMergedRegion(new NPOI.SS.Util.CellRangeAddress(0, 0, 0, table.Columns.Count - 1));
                    }
                    #endregion

                    #region 列头及样式
                    {
                        //HSSFRow headerRow = sheet.CreateRow(1);
                        IRow headerRow;
                        //if (!string.IsNullOrEmpty(headerText))
                        //{
                        //    headerRow = sheet.CreateRow(0);
                        //}
                        //else
                        //{
                        headerRow = sheet.CreateRow(1);
                        //}
                        ICellStyle headStyle = hssfworkbook.CreateCellStyle();
                        headStyle.Alignment = HorizontalAlignment.CENTER;
                        IFont font = hssfworkbook.CreateFont();
                        font.FontHeightInPoints = 10;
                        font.Boldweight = 700;
                        headStyle.SetFont(font);

                        for (int i = 0; i < columnName.Length; i++)
                        {
                            headerRow.CreateCell(i).SetCellValue(columnTitle[i]);
                            headerRow.GetCell(i).CellStyle = headStyle;
                            //设置列宽
                            if ((colWidth[i] + 1) * 256 > 30000)
                            {
                                sheet.SetColumnWidth(i, 10000);
                            }
                            else
                            {
                                sheet.SetColumnWidth(i, (colWidth[i] + 1) * 256);
                            }
                        }
                        /*
                        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] + 1) * 256);
                        }
                         * */
                    }
                    #endregion
                    //if (!string.IsNullOrEmpty(headerText))
                    //{
                    //    rowIndex = 1;
                    //}
                    //else
                    //{
                    rowIndex = 2;
                    //}

                }
                #endregion

                #region 填充数据

                IRow dataRow = sheet.CreateRow(rowIndex);
                for (int i = 0; i < columnName.Length; i++)
                {
                    ICell newCell = dataRow.CreateCell(i);

                    string drValue = row[columnName[i]].ToString();

                    switch (table.Columns[columnName[i]].DataType.ToString())
                    {
                        case "System.String"://字符串类型
                            if (drValue.ToUpper() == "TRUE")
                                newCell.SetCellValue("是");
                            else if (drValue.ToUpper() == "FALSE")
                                newCell.SetCellValue("否");
                            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);
                            if (boolV)
                                newCell.SetCellValue("是");
                            else
                                newCell.SetCellValue("否");
                            break;
                        case "System.Int16"://整型
                        case "System.Int32":
                        case "System.Int64":
                        case "System.Byte":
                            int intV = 0;
                            int.TryParse(drValue, out intV);
                            newCell.SetCellValue(intV);
                            break;
                        case "System.Decimal"://浮点型
                        case "System.Double":
                            double doubV = 0;
                            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++;
            }

            return hssfworkbook;
        }
    }
}

使用的过程中需要将实体对象集合转换成 DataTable

使用方法：

#region 将指定的集合转换成数据表...

        /// <summary>
        /// 将指定的集合转换成DataTable。
        /// </summary>
        /// <param name="list">将指定的集合。</param>
        /// <returns>返回转换后的DataTable。</returns>
        public static DataTable ListToDataTable(IList list)
        {
            DataTable table = new DataTable();
            if (list.Count > 0)
            {
                PropertyInfo[] propertys = list[0].GetType().GetProperties();
                foreach (PropertyInfo pi in propertys)
                {
                    Type pt = pi.PropertyType;
                    if ((pt.IsGenericType) && (pt.GetGenericTypeDefinition() == typeof(Nullable<>)))
                    {
                        pt = pt.GetGenericArguments()[0];
                    }
                    table.Columns.Add(new DataColumn(pi.Name, pt));
                }

                for (int i = 0; i < list.Count; i++)
                {
                    ArrayList tempList = new ArrayList();
                    foreach (PropertyInfo pi in propertys)
                    {
                        object obj = pi.GetValue(list[i], null);
                        tempList.Add(obj);
                    }
                    object[] array = tempList.ToArray();
                    table.LoadDataRow(array, true);
                }
            }
            return table;
        }

        #endregion

        #region 导出数据...

        private void ExportData(List<ProductInfo> productList)
        {
            var exportDataList =
                (from productInfo in ProductList
                  new
                 {
                     Code = productInfo.Code,
                     Name = productInfo.Name,
                     DeptName = productInfo.DeptName,
                     ProjectName = productInfo.ProjectName,
                     CategoryName = productInfo.CategoryName,
                     Intro = productInfo.Intro,
                     Level = productInfo.Level,
                     Objective = productInfo.Objective
                 }).ToList();

            DataTable table = ListToDataTable(exportDataList);
            string[] strFields = { "Code", "Name", "DeptName", "ProjectName", "CategoryName", "Intro", "Level", "Objective" };
            string[] strFieldsName = { "编码", "名称", "所属部门", "所属项目", "分类", "简介", "等级", "目标" };
            ExcelHelper.Write(table, "产品表", "产品表", strFields, strFieldsName, "产品表.xls");
        }

        #endregion