NOPI导出标准格式Excel

添加引用NOPI，官网下载地址NOPI下载地址选择合适的版本，根据你自己的项目的.net版本选择引用的dll有2.0和4.0的，vs2010以上可以选4.0的 剩下的都选2.0的吧，引用一下NPOI.dll就行其他的，不用引用，如果用到nopi的其他功能自行百度引用

using NPOI.HSSF.UserModel;
using NPOI.SS.UserModel;

        private void Excel(DataTable dt, string FileName)
        {
            try
            {
                HSSFWorkbook workbook = new HSSFWorkbook();
                ISheet sheet = workbook.CreateSheet("Sheet1");

                ICellStyle HeadercellStyle = workbook.CreateCellStyle();
                HeadercellStyle.BorderBottom = NPOI.SS.UserModel.BorderStyle.Thin;
                HeadercellStyle.BorderLeft = NPOI.SS.UserModel.BorderStyle.Thin;
                HeadercellStyle.BorderRight = NPOI.SS.UserModel.BorderStyle.Thin;
                HeadercellStyle.BorderTop = NPOI.SS.UserModel.BorderStyle.Thin;
                HeadercellStyle.Alignment = NPOI.SS.UserModel.HorizontalAlignment.Center;
                //字体
                NPOI.SS.UserModel.IFont headerfont = workbook.CreateFont();
                headerfont.Boldweight = (short)FontBoldWeight.Bold;
                HeadercellStyle.SetFont(headerfont);

                //用column name 作为列名
                int icolIndex = 0;
                IRow headerRow = sheet.CreateRow(0);
                foreach (DataColumn item in dt.Columns)
                {
                    ICell cell = headerRow.CreateCell(icolIndex);
                    cell.SetCellValue(item.ColumnName);
                    cell.CellStyle = HeadercellStyle;
                    icolIndex++;
                }

                ICellStyle cellStyle = workbook.CreateCellStyle();

                //为避免日期格式被Excel自动替换，所以设定 format 为 『@』 表示一率当成text來看
                cellStyle.DataFormat = HSSFDataFormat.GetBuiltinFormat("@");
                cellStyle.BorderBottom = NPOI.SS.UserModel.BorderStyle.Thin;
                cellStyle.BorderLeft = NPOI.SS.UserModel.BorderStyle.Thin;
                cellStyle.BorderRight = NPOI.SS.UserModel.BorderStyle.Thin;
                cellStyle.BorderTop = NPOI.SS.UserModel.BorderStyle.Thin;


                NPOI.SS.UserModel.IFont cellfont = workbook.CreateFont();
                cellfont.Boldweight = (short)FontBoldWeight.Normal;
                cellStyle.SetFont(cellfont);

                //建立内容行
                int iRowIndex = 1;
                int iCellIndex = 0;
                foreach (DataRow Rowitem in dt.Rows)
                {
                    IRow DataRow = sheet.CreateRow(iRowIndex);
                    foreach (DataColumn Colitem in dt.Columns)
                    {

                        ICell cell = DataRow.CreateCell(iCellIndex);
                        cell.SetCellValue(Rowitem[Colitem].ToString());
                        cell.CellStyle = cellStyle;
                        iCellIndex++;
                    }
                    iCellIndex = 0;
                    iRowIndex++;
                }

                //自适应列宽度
                for (int i = 0; i < icolIndex; i++)
                {
                    sheet.AutoSizeColumn(i);
                }

                //写Excel
                //FileStream file = new FileStream(FileName, FileMode.OpenOrCreate);
                System.IO.MemoryStream file = new System.IO.MemoryStream();
                workbook.Write(file);
                Response.AddHeader("Content-Disposition", "attachment; filename=" + Server.UrlEncode(FileName) + ".xls");
                Response.BinaryWrite(file.ToArray());
                workbook = null;
                file.Close();
                file.Dispose();
            }
            catch (Exception ex)
            {
                Response.Write("<script>alert('" + ex.Message + "')</scrit>");
            }
        }