数据库的备份问题

我要说的一点就是备份路径的问题，我做 了好久，后来与一个网友两个人不停的想，后来才做出来了，结果与大家分享一下，这个路径，我觉得
 //数据备份
    protected void btnBackDB_Click(object sender, EventArgs e)
    {    
        Backup oBackUp = new BackupClass();
        SQLServer oSqlServer = new SQLServerClass();
        try
        {
            oSqlServer.LoginSecure = false;
            oSqlServer.Connect("localhost", "sa", "123456");
            oBackUp.Action = SQLDMO_BACKUP_TYPE.SQLDMOBackup_Database;

            oBackUp.Database = "WeifangEducationDB";

            //string url = Server.MapPath("BackDb");
            //if (!Directory.Exists(url)) Directory.CreateDirectory(url);Path.Combine(url, "weifangeducationdb.bak")
，这个是网友提供的
            string url = Server.MapPath("back");
//这个是我自己写的
 if (!Directory.Exists(url))
            {
                DirectoryInfo info = Directory.CreateDirectory(url);
            }
           //格式化时间
            string datetim = DateTime.Now.ToString("yyyyMMddHHmmss");
            datetim = datetim.Replace(" ","");
            datetim = datetim.Replace("-","");
            datetim = datetim.Replace(":","");
            datetim = datetim.Substring(0,8);

            oBackUp.Files = url + @"\WeifangEducationDB_"+datetim+".bak";
            Response.Write("<script>alert('" + url + "')</script>");
            oBackUp.BackupSetName = "WeifangEducationDB";
            oBackUp.BackupSetDescription = "数据库备份";
            oBackUp.Initialize = true;
            oBackUp.SQLBackup(oSqlServer);
            lblMessages.Text = "备份成功！";

            this.lblMessages.Text = "备份成功!";
        }
        catch (Exception ex)
        {
            lblMessages.Text = "备份失败" + ex.Message;
        }
        finally
        {
            oSqlServer.DisConnect();
        }


    }