NPOI导出Excel示例

摘要：使用开源程序NPOI导出Excel示例。NPOI首页地址：http://npoi.codeplex.com/，NPOI示例博客：http://tonyqus.sinaapp.com/。

示例编写环境：

操作系统：Windows7 Ultimate SP1 64bit

开发软件：Visual Studio Ultimate 2012 Update 3

Office版本：Office Home and Student 2010

NPOI版本：NPOI 2.0

示例界面如下：

本示例中使用到的命名空间：

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

导出按钮代码：

protected void btnExportClick(object sender, EventArgs e)
{
    // 文件名最好使用英文，中文可能会出现乱码或者丢失文件后缀
    string filename = "ReportExport" + DateTime.Now.ToString("yyyy-MM-dd_HH-mm-ss");
    Response.Clear();
    Response.ContentType = "application/vnd.ms-excel";
    Response.AppendHeader("Content-Type", "applicationnd.ms-excel");
    Response.AppendHeader("Content-Disposition", "attachment;filename=" + filename + ".xls");

    // getData()函数返回一个DataTable类型，在本实例中用于获得要导出的数据，可根据项目情况替换该函数
    Response.BinaryWrite(getExportContent(getData()).GetBuffer());
    Response.Flush();
    // 若使用Response.End方法会导致ThreadAbortException 异常，使用下面的语句替换Response.End方法
    HttpContext.Current.ApplicationInstance.CompleteRequest();
}

负责生成导出信息的方法getExportContent示例代码如下：

private MemoryStream getExportContent(DataTable table)
{
    // 添加Excel元数据信息
    HSSFWorkbook book = new HSSFWorkbook();
    DocumentSummaryInformation dsi = PropertySetFactory.CreateDocumentSummaryInformation();
    dsi.Company = "MyCompany";
    book.DocumentSummaryInformation = dsi;

    SummaryInformation si = PropertySetFactory.CreateSummaryInformation();
    si.Subject = "MySubject";
    book.SummaryInformation = si;

    // 声明必要的变量
    MemoryStream ms = new MemoryStream();
    ISheet sheet = book.CreateSheet("sheet1");
    IRow erow = sheet.CreateRow(0);

    // 设置列宽，列宽的单位是256分之一字符，所以10*256表示10个字符宽度
    sheet.SetColumnWidth(1, 20 * 256);
    sheet.SetColumnWidth(2, 20 * 256);
    sheet.SetColumnWidth(3, 10 * 256);
    sheet.SetColumnWidth(4, 10 * 256);

    // 增加表头
    buildSheetTitle(book);

    // 增加内容，标题占两行，从第三行添加数据内容。
    // 在NPOI中行列以0作为起始
    int rindex = 2;
    foreach (DataRow r in table.Rows)
    {
        erow = sheet.CreateRow(rindex);
        // 序号
        erow.CreateCell(0).SetCellValue(rindex - 1);
        for (int c = 0; c < table.Columns.Count; c++)
        {
            erow.CreateCell(c + 1).SetCellValue(r[c].ToString());
        }
        rindex++;
    }
    //  对相同的列进行纵向合并
    mergeColumn(book);


    book.Write(ms);
    ms.Flush();
    ms.Position = 0;
    return ms;
}

增加表头方法buildSheetTitle示例代码：

private void buildSheetTitle(HSSFWorkbook book)
{
    // 定义必要变量
    ISheet sheet = book.GetSheetAt(0);
    IRow erow = sheet.CreateRow(0);
    ICell cell = null;
    // 单元格样式
    ICellStyle style = book.CreateCellStyle();
    style.Alignment = HorizontalAlignment.CENTER;
    style.VerticalAlignment = VerticalAlignment.CENTER;
    IFont font = book.CreateFont();
    font.FontHeightInPoints = 12;
    font.FontName = "宋体";
    style.SetFont(font);

    // 增加第一行标题
    cell = erow.CreateCell(0);
    cell.SetCellValue("序号");
    cell.CellStyle = style;
    sheet.AddMergedRegion(new CellRangeAddress(0, 1, 0, 0));

    cell = erow.CreateCell(1);
    cell.SetCellValue("装置名称");
    cell.CellStyle = style;
    sheet.AddMergedRegion(new CellRangeAddress(0, 1, 1, 1));

    cell = erow.CreateCell(2);
    cell.SetCellValue("物料信息");
    cell.CellStyle = style;
    sheet.AddMergedRegion(new CellRangeAddress(0, 0, 2, 3));

    // 增加第二行标题
    erow = sheet.CreateRow(1);
    cell = erow.CreateCell(2);
    cell.SetCellValue("物料名称");
    cell.CellStyle = style;
    cell = erow.CreateCell(3);
    cell.SetCellValue("小计");
    cell.CellStyle = style;
}

合并单元格方法mergeColumn示例代码如下：

private void mergeColumn(HSSFWorkbook book)
{
    ISheet sheet = book.GetSheetAt(0);
    int cunit = 1;
    // 合并单元格跨越的行数
    int rspan = 0;
    // 需合并单元格的起始行，前两行为标题，默认起始行是第三行
    int srow = 2;

    // 单元格字体样式
    IFont font = book.CreateFont();
    font.FontHeightInPoints = 12;
    font.FontName = "宋体";

    // 非合并单元格样式
    ICellStyle style = book.CreateCellStyle();
    style.SetFont(font);

    // 合并单元格样式
    ICellStyle mstyle = book.CreateCellStyle();
    mstyle.Alignment = HorizontalAlignment.CENTER;
    mstyle.VerticalAlignment = VerticalAlignment.CENTER;
    mstyle.SetFont(font);


    // 合并单元格
    string oldvalue = string.Empty;
    for (int r = 2; r < sheet.PhysicalNumberOfRows; r++)
    {
        if (sheet.GetRow(r).GetCell(cunit).StringCellValue == oldvalue)
        {
            rspan++;
        }
        else
        {
            // 添加合并区域
            sheet.AddMergedRegion(new CellRangeAddress(srow, srow + rspan, 1, 1));
            oldvalue = sheet.GetRow(r).GetCell(cunit).StringCellValue;
            srow = r;
            rspan = 0;
        }
    }

    // 对未合并的单元格进行合并
    if (rspan != 0)
    {
        sheet.AddMergedRegion(new CellRangeAddress(srow, srow + rspan, 1, 1));
    }

    // 调整合并单元格的样式
    for (int c = 0; c < 4; c++)
    {
        for (int r = 2; r < sheet.PhysicalNumberOfRows; r++)
        {
            if (c == cunit)
            {
                sheet.GetRow(r).GetCell(c).CellStyle = mstyle;
            }
            else
            {
                sheet.GetRow(r).GetCell(c).CellStyle = style;
            }
        }
    }
}

导出后的文件内容：