前台的话不多说，本次只详细说下后台导出数据库中的二进制字段，上传下次有时间再说，有比较急的可以留言我

之前在网上搜了关于下载导出二进制字段的资料，发现都不是我想要的，都只是把上传的文件放到服务器然后下载这个文件，并不是把数据库中的二进制使用excel导出，下面我就贴出下我自己写的方法，可以供给需要的人，当然也有大牛可能比我写的好，您可以选择不看或提点下建议！

最后本文数原创，转载请注明出处或链接！

/// <summary>
/// 下载卡券导入日志
/// </summary>
/// <param name="e"></param>
private void EditBLL(DataGridCommandEventArgs e)
{
if (e.CommandName == "DownLoad")//e 前台绑定事件commandName
{
String sFileId = e.Item.Cells[0].Text.Trim();
VirtualCouponsManagebll bll = new VirtualCouponsManagebll();
DataTable dt = bll.GetCardcouponsFileLogToExcel(sFileId);//查询出数据
if (dt.Rows.Count <= 0)
{
MessageBox("查询卡券导入日志失败");
return;
}
string sGoodsName = dt.Rows[0]["GoodsName"].ToString();
string sCreateTime = Convert.ToDateTime(dt.Rows[0]["CreateDate"].ToString()).ToString("yyyyMMddHHmmss");
string sFileName = sGoodsName + sCreateTime + ".xlsx";
DataSet ds = StreamConvertDataSet((byte[])dt.Rows[0]["CardCouponsFile"], sFileName);
if (ds == null || ds.Tables[0].Rows.Count <= 0)
{
MessageBox("卡券数据由byte数组转DataSet失败");
return;
}
ExportTableStrBul(ds.Tables[0], "虚拟商品：" + sGoodsName + "_卡券导入数据", sCreateTime);
}
}

/// <summary>
/// byte数组转成DataSet
/// </summary>
/// <param name="bytes"></param>
/// <param name="sFileName"></param>
/// <returns></returns>
private DataSet StreamConvertDataSet(byte[] bytes, string sFileName)
{
MemoryStream _MStream = new MemoryStream(bytes);
string path = AppDomain.CurrentDomain.DynamicDirectory + sFileName;
System.IO.FileStream Filestream = new System.IO.FileStream(path, System.IO.FileMode.Create);
_MStream.CopyTo(Filestream);
IExcelDataReader excelReader = null;
DataSet ds = null;

try
{
excelReader = ExcelReaderFactory.CreateOpenXmlReader(Filestream);

excelReader.IsFirstRowAsColumnNames = true;
ds = excelReader.AsDataSet();
}
catch (Exception)
{
Filestream.Close();
_MStream.Close();
excelReader.Close();
}
finally
{
excelReader.Close();
Filestream.Close();
_MStream.Close();
if (File.Exists(path))
{
File.Delete(path);
}
}
return ds;
}

/// <summary>
/// 生成EXCEL
/// </summary>
/// <param name="dt">数据</param>
/// <param name="sFileName">文件名</param>
/// <param name="sCreateTime">文件名</param>
public void ExportTableStrBul(DataTable dt, string sFileName, string sCreateTime)
{
Response.Clear();
Response.Buffer = true;
Response.Charset = "GB2312";
Response.AppendHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(sFileName) + sCreateTime + ".xls");
Response.ContentEncoding = System.Text.Encoding.GetEncoding("GB2312");//设置输出流为简体中文
Response.ContentType = "application/ms-excel";//设置输出文件类型为excel文件。
EnableViewState = false;

DataView view = dt.DefaultView;
string[] strArr = { "卡券", "结束日期" };//"TotalRMB",
//从 DataView 创建新的 DataTable，可以使用 ToTable 方法将所有行和列或数据的一个子集复制到新的 DataTable 中
DataTable newTable = view.ToTable("DownTab",
true, strArr);

dt = newTable;

StringBuilder sb = new StringBuilder();
int count = 0;

//--写入EXCEL
sb.AppendLine("<meta http-equiv=\"Content-Type\" content=\"text/html; charset=gb2312\">");
sb.AppendLine("<table cellspacing=\"0\" cellpadding=\"5\" rules=\"all\" border=\"1\">");
//写出列名
sb.AppendLine("<tr style=\"font-weight: bold; white-space: nowrap;\">");
foreach (DataColumn column in dt.Columns)
{
sb.AppendLine("<td>" + column.ColumnName + "</td>");
}
sb.AppendLine("</tr>");
sb = sb.Replace("卡券", "卡券");
sb = sb.Replace("结束日期", "结束日期");

//写出数据
foreach (DataRow row in dt.Rows)
{
sb.Append("<tr>");
foreach (DataColumn column in dt.Columns)
{
if (column.ColumnName.Equals("卡券"))
{
sb.Append("<td style=\"vnd.ms-excel.numberformat:@\">" + ReplaceChar(row[column].ToString()) + "</td>");
}
else
{
sb.Append("<td>" + row[column].ToString() + "</td>");
}
}
sb.AppendLine("</tr>");
count++;
}
sb.AppendLine("</table>");

Response.Write(sb.ToString());
Response.End();
}