เรื่องการบันทึกเวลา Login กับ Logout เป็นเว็บ vb c# (Web-ASP.NET)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

//เพิ่ม Namespace 
using System.Data;
using System.Data.SqlClient;

public partial class LoginStafft : System.Web.UI.Page
{

    

    protected void Page_Load(object sender, EventArgs e)
    {
        
                
    }
    protected void btnLoginStaff_Click(object sender, EventArgs e)
    {

        //เปิด database
        string strConnnection = "Data Source=.\\SQLEXPRESS;AttachDbFilename=|DataDirectory|\\dbAccount.mdf;Integrated Security=True;User Instance=True";
        SqlConnection Conn = new SqlConnection(strConnnection);
        Conn.Open();


        //ใส่ code


        string sqlUserName = "select * from tbPersonnel where Username='" + tbxUsernameStaff.Text + "'and Password = '" + tbxPasswordStaff.Text + "'";

               
        
        SqlCommand com = new SqlCommand(sqlUserName, Conn);

        //run sql ค่าถูกดึงออกมาไว้ใน dr
        SqlDataReader dr = com.ExecuteReader();





        //ประกาศ New Cookies
        HttpCookie ck = new HttpCookie("Account");

        //ใส่ค่า
       

        //กำหนดวันหมดอายุ
        ck.Expires = DateTime.Now.AddMinutes(5);

        // เก็บ Cookie ลงระบบ
        Response.Cookies.Add(ck);




        //อ่านค่า
        

        if (dr.HasRows)
        {
   
             string strsql= "update tbPersonnel set Datetime=getdate() where Username='" + tbxUsernameStaff.Text + "'and Password = '"+ tbxPasswordStaff.Text + "'";

               
        SqlCommand comm = new SqlCommand(strsql, Conn);
        comm.ExecuteNonQuery()
        
 
               
               
            while (dr.Read())
            {
               




                switch (dr.GetString(3))
                {

                    case "Manager":


                        //link ไปหน้าผู้จัดการ
                      
                        ck.Values["Status"] = dr.GetString(5);
                        ck.Values["Role"] = dr.GetString(3);
                        ck.Values["Name"] = dr.GetString(5);
                        
                        
                        


                        Response.Redirect("Manager.aspx");
                        break;


                    case "Employee":

                        //link ไปหน้า Employee
                        ck.Values["Status"] = dr.GetString(5);
                        ck.Values["Role"] = dr.GetString(3);
                        ck.Values["Name"] = dr.GetString(5);
                        Response.Redirect("Employee.aspx");
                        break;

                    case "Front":

                        //link ไปหน้า Employee
                        ck.Values["Status"] = dr.GetString(5);
                        ck.Values["Role"] = dr.GetString(3);
                        ck.Values["Name"] = dr.GetString(5);
                        Response.Redirect("Front.aspx");
                        break;

                }

            }
        }

        else
        {
            lbCheck.Text = ("ผิดพลาด กรุณาตรวจสอบข้อมูลใหม่");
        }
        //ปิด database
        Conn.Close();
}

    protected void btnCencelStaff_Click(object sender, EventArgs e)
    {
        tbxUsernameStaff.Text = "";
        tbxPasswordStaff.Text = "";
    }
}