訂單生成序列號代碼

strOrderFlag = "未審覈";
        string dt = DateTime.Now.ToString();
        stryundanhao = "暫無快遞號";
        CW.BLL.Orders bllOrders = new CW.BLL.Orders();
        CW.Model.Orders model = new CW.Model.Orders();
        model.MemberID = Convert.ToInt32(Session["UserLoginID"].ToString());
        model.ProductID = Convert.ToInt32(Session["orderproid"].ToString());
        model.OrderFlag = strOrderFlag;
        model.OrderNum = Convert.ToString(TextBox1.Text.Trim());
        model.OrderTime = Convert.ToString(dt.ToString());
        model.yundanhao = stryundanhao;
        model.beizhu = Convert.ToString(TextBox2.Text.Trim());
        //生成訂單序列號
        Random random = new Random();

        string strRandom = (random.Next(1, int.MaxValue).ToString() + "000").Substring(0, 4);

        string orderId = Session["UserLoginID"] + DateTime.Now.ToString("yyyyMMddHHmmssffff") + strRandom;
        //以上結束
        model.OrderStringID = orderId;
        bllOrders.Add(model);
        CW.Common.ShowInfo.AlertAndRedirect("提交訂單成功！", "index.aspx", this.Page);