上传图片到数据库，下载图片到本地

/// <summary>
    /// 上传图片到数据库
    /// </summary>
    /// <param name="UpFiles">html对象</param>
    /// <param name="fieldname">字段名</param>
    public void UploadfiletoDb(HtmlInputFile UpFiles1,HtmlInputFile UpFiles2,HtmlInputFile UpFiles3,string m_name)
    {
        SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["CS"].ToString());
        HttpPostedFile UpFile1 = UpFiles1.PostedFile;
        HttpPostedFile UpFile2 = UpFiles2.PostedFile;
        HttpPostedFile UpFile3 = UpFiles3.PostedFile;
        FileLength1 = UpFile1.ContentLength;           //记录文件长度 
        FileLength2 = UpFile2.ContentLength;           //记录文件长度
        FileLength3 = UpFile3.ContentLength;           //记录文件长度 
        //try
        //{
            if ((FileLength1 == 0) || (FileLength2 == 0) || (FileLength3 == 0))
            {   //文件长度为零时  
                Response.Write("<script>window.alert('请你选择你要上传的文件')</script>");
            }
            else
            {
                Byte[] FileByteArray1 = new Byte[FileLength1];       //图象文件临时储存Byte
                Byte[] FileByteArray2 = new Byte[FileLength2];       //图象文件临时储存Byte
                Byte[] FileByteArray3 = new Byte[FileLength3];       //图象文件临时储存Byte 
                Stream StreamObject1 = UpFile1.InputStream;             //建立数据流对像
                Stream StreamObject2 = UpFile2.InputStream;             //建立数据流对像
                Stream StreamObject3 = UpFile3.InputStream;             //建立数据流对像
                StreamObject1.Read(FileByteArray1, 0, FileLength1);
                StreamObject2.Read(FileByteArray1, 0, FileLength2);
                StreamObject3.Read(FileByteArray1, 0, FileLength3);
                String SqlCmd = "update Member_tab set photofyj=@Image1,identitycardfyj=@Image2,presscardfyj=@Image3) where MemberName=@Mn";
                SqlCommand CmdObj = new SqlCommand(SqlCmd, con);
                CmdObj.Parameters.Add("@Image1", SqlDbType.Binary, FileLength1).Value = FileByteArray1;
                CmdObj.Parameters.Add("@Image2", SqlDbType.Binary, FileLength2).Value = FileByteArray2;
                CmdObj.Parameters.Add("@Image3", SqlDbType.Binary, FileLength3).Value = FileByteArray3;
                CmdObj.Parameters.Add("@Mn", SqlDbType.NVarChar, 8).Value = m_name;

                con.Open();
                CmdObj.ExecuteNonQuery();
                con.Close();
            }
        //}
        //catch (Exception ex)
        //{
        //    con.Close();
        //}
    }

//读取图片到页面

 public void getimage(string mxingming,string str_fieldname)
    {
        SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["CS"].ToString());
        string p_sql = "SELECT " + str_fieldname + " FROM Member_tab WHERE MemberName = @MN";
        SqlCommand CmdObj = new SqlCommand(p_sql, con);
        CmdObj.Parameters.Add("@MN", SqlDbType.NVarChar).Value = mxingming;
        con.Open();
        SqlDataReader SqlReader = CmdObj.ExecuteReader();
        if (SqlReader.Read())
        {
            if (SqlReader[str_fieldname]!= null)
            {
                try
                {
                    byte[] photo = (byte[])SqlReader[str_fieldname];
                    Response.OutputStream.Write(photo, 0, photo.Length);
                }
            catch (Exception ex)
            {

            }
                Response.End();
                con.Close();
            }
        }

    }