.Net 使用NPOI 实现Excel的简单导入导出 - Ran0 - 博客园

//创建不同版本的文件， excel2003版 或2007+版

 

public IWorkbook BuildWorkbook(DataTable dt, string file)
    {
        IWorkbook book;

        string fileExt = Path.GetExtension(file).ToLower();

        if (fileExt == ".xlsx")
        { book = new XSSFWorkbook(); }
        else if (fileExt == ".xls")
        { book = new HSSFWorkbook(); }
        else { book = null; }

        //var book = new HSSFWorkbook();

        ISheet sheet1 = book.CreateSheet("Sheet1");
        ISheet sheet2 = book.CreateSheet("Sheet2");

        //填充数据
        for (int i = 0; i < dt.Rows.Count; i++)
        {
            if (i < 65536)
            {
                IRow drow = sheet1.CreateRow(i);
                for (int j = 0; j < dt.Columns.Count; j++)
                {
                    ICell cell = drow.CreateCell(j, CellType.String);
                    cell.SetCellValue(dt.Rows[i][j].ToString());
                }
            }
            if (i >= 65536) //再创建一个sheet
            {
                IRow drow = sheet2.CreateRow(i - 65536);
                for (int j = 0; 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 = 0; i <= dt.Columns.Count; i++)
        {
            sheet1.AutoSizeColumn(i, true);
            sheet2.AutoSizeColumn(i, true);
        }
        return book;
    }

 

//导出至excel文件

public void ExportExcel(DataTable dt, string fileName = "")
    {
        ////////生成Excel
        IWorkbook book = BuildWorkbook(dt, fileName);

       

       //web 下载
        if (fileName == "")
            fileName = string.Format("{0:yyyyMMddHHmmssffff}", DateTime.Now) + ".xls";

 

        fileName = fileName.Trim();

        HttpResponse httpResponse = HttpContext.Current.Response;
        httpResponse.Clear();
        httpResponse.Buffer = true;
        httpResponse.Charset = Encoding.UTF8.BodyName;
        httpResponse.AppendHeader("Content-Disposition", "attachment;filename=" + fileName);
        httpResponse.ContentEncoding = Encoding.UTF8;
        httpResponse.ContentType = "application/vnd.ms-excel; charset=UTF-8";

        book.Write(httpResponse.OutputStream);
        httpResponse.End(); 
    }