ดู code Login ให้หน่อยค่ะ ... รบกวนช่วยดู code ให้หน่อยค่ะช มันติ ดตรงที่ แก้ไม่ได้ซักที

Imports System.Data.SqlClient
Imports System.Data
Imports System.Web.HttpContext
Imports System.Data.Common
Partial Class _Default
    Inherits System.Web.UI.Page
    Dim addUser As Data.SqlClient.SqlParameter
    Dim con As New Data.SqlClient.SqlConnection()
    Dim cmd As New Data.SqlClient.SqlCommand()
    Dim isLogin As Boolean = False

    Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
        con.ConnectionString = "Data Source=YTC-MDH-N141;Initial Catalog=User;User ID=sa;Password=root"
        IsCheck(UsernameTextBox.Text, PasswordTextBox.Text)

    End Sub

    Private Sub IsCheck(ByVal username As String, ByVal password As String)
        Dim param1 As IDbDataParameter = Nothing
        Dim param2 As IDbDataParameter = Nothing

        Dim factory As DbProviderFactory = DbProviderFactories.GetFactory("System.Data.SqlClient")
        Dim con As IDbConnection = factory.CreateConnection()
        con.ConnectionString = "Addr =.\Sqlexpress;Database =LoginDB;Integrated Security=SSPI"
        cmd = factory.CreateCommand()
        cmd.Connection = con

        cmd.CommandText = "SELECT m.Username , m.Password FROM Username AS m WHERE m.Username = @Username AND m.Password = @Password"
        param1 = factory.CreateParameter()
        param1.ParameterName = "@Username"
        param1.DbType = DbType.[String]
        param1.Value = username
        param2 = factory.CreateParameter()
        param2.ParameterName = "@Password"
        param2.DbType = DbType.[String]
        param2.Value = password
        cmd.Parameters.Add(param1)
        cmd.Parameters.Add(param2)

        Using reader As IDataReader = cmd.ExecuteReader()
            While reader.Read()
                If username = reader.GetString(0) Then
                    If password = reader.GetString(1) Then
                        'ถ้า username,password ตรงกับฐานข้อมูลให้กำหนดค่าจริงให้กับตัวแปร isLogin 
                        isLogin = True
                    Else
                        'ถ้า password ไม่ตรงก็ให้เป็น false 
                        isLogin = False
                    End If
                Else
                    'ถ้า username ไม่ตรงกับฐานข้อมูลก็ให้เป็น false 
                    isLogin = False
                End If
            End While
            reader.Close()
            con.Close()
        End Using

        If isLogin Then
            'เรียกใช้ ticket 
            MyTicket(username)
        Else
            Response.Write("Login Failed")
        End If
    End Sub

    Private Sub MyTicket(ByVal username As String)
        'Ticket 
        Dim ticket As FormsAuthenticationTicket
        'สร้าง Ticket 
        Dim cookie As HttpCookie = Nothing
        'สร้าง cookies เพื่อเก็บค่าเป็น cookies 
        ticket = New FormsAuthenticationTicket(1, username, DateTime.Now, DateTime.Now.AddMinutes(5), False, "")
        Dim encrypt As String = FormsAuthentication.Encrypt(ticket)
        cookie = New HttpCookie(FormsAuthentication.FormsCookieName, encrypt)
        Response.Cookies.Add(cookie)
        Response.Redirect("page1.aspx")
    End Sub


End Class