asp.net 上传下载 输出二进制流

using System;  
using System.Collections;  
using System.Configuration;  
using System.Data;  
using System.Linq;  
using System.Web;  
using System.Web.Security;  
using System.Web.UI;  
using System.Web.UI.HtmlControls;  
using System.Web.UI.WebControls;  
using System.Web.UI.WebControls.WebParts;  
using System.Data.SqlClient;  
using System.IO;  
namespace Delegate  
{  
    public partial class ReadStream : System.Web.UI.Page  
    {  
        protected void Page_Load(object sender, EventArgs e)  
        {  
        }  
        /// <summary>  
        /// 将上传的文件转换成二进制流保存在数据库  
        /// </summary>  
        /// <param name="sender"></param>  
        /// <param name="e"></param>  
        protected void Button1_Click(object sender, EventArgs e)  
        {  
            SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["sql"].ToString());  
            string strSql="insert into test(timage)values(@images)";//保存二进制流的方式需参数的形式  
            SqlCommand cmd = new SqlCommand(strSql, conn);&n