.net从数据库二进制字段下载附件(文件),解决中文乱码

if (ViewState["AttFileTable"] != null)
        {
            DataTable dt_a = (DataTable)ViewState["AttFileTable"];
           
            DataRow[] rows = dt_a.Select("fileID=" + 文件ID);

            if (rows.Length > 0)
            {
                byte[] filebyte = (byte[])rows[0]["fileContent"];//二进制字段内容
                string fileName = rows[0]["realName"].ToString();
                Response.Clear();
                Response.AppendHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8));//设置编码，解决下载文件名乱码
                Response.AppendHeader("Content-Length", filebyte.Length.ToString());
                Response.ContentType = "application/octet-stream";
                Response.OutputStream.Write(filebyte, 0, filebyte.Length);                
                Response.End();
            }
            else
            {
                cls_Common.alert("不存在");
            }
        }