Login authentication asp.net with active directory - asp.net

Question

i have a project where i need to use the active directory for login to a website made in asp.net, i follow this tutorial....
Active Directory Authentication from ASP .NET
now i want to get the groups of the user, i tried the next code in the default.aspx.vb page but doesn't work..
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
Response.Write("Hello, " + Server.HtmlEncode(User.Identity.Name))
Dim id As FormsIdentity = CType(User.Identity, FormsIdentity)
If id IsNot Nothing Then
Dim ticket As FormsAuthenticationTicket = id.Ticket
Response.Write("<p/>TicketName: " + ticket.Name)
Response.Write("<br/>Cookie Path: " + ticket.CookiePath)
Response.Write("<br/>Ticket Expiration: " + ticket.Expiration.ToString())
Response.Write("<br/>Expired: " + ticket.Expired.ToString())
Response.Write("<br/>Persistent: " + ticket.IsPersistent.ToString())
Response.Write("<br/>IssueDate: " + ticket.IssueDate.ToString())
Response.Write("<br/>UserData: " + ticket.UserData)
Response.Write("<br/>Version: " + ticket.Version.ToString())
End If
End Sub

Answer 1

I find a better solution, is more easy than any answer that i find on the internet.
First i create a class to validate if an user is in a group in the active directory:
Imports System.Security.Principal
Public Class AutorizationFun
Dim access As Boolean = False
Dim id As WindowsIdentity = WindowsIdentity.GetCurrent()
Public User As WindowsPrincipal = New WindowsPrincipal(id)
Region "Groups Verification"
'Belongs to sample group
Private Function inSampleGroup() As Boolean
Return User.IsInRole("bth0\GG BTUC-SAMPLEGROUP")
End Function
Private Function inSampleGroup2() As Boolean
Return User.IsInRole("bth0\GG BTUC-SAMPLEGROUP2")
End Function
End Region
Public Function ProgramsAccsess(ByVal vPage As String) As Boolean
access = False
Select Case vPage
Case "~/Sample.aspx"
If inSampleGroup() Then
access = True
End If
'---------------------------------------------------------------------
End Select
'*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
'access = True
'*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
Return access
End Function
End Class
Then you have to create a function in the code behind of all pages:
'create var
Dim ValidateUser As New AutorizationFun
Protected Sub VerifyAccessPage()
If ValidateUser.ProgramsAccsess(Request.AppRelativeCurrentExecutionFilePath) = False Then
Response.Redirect("~/DeniedAccess.aspx")
End If
End Sub
And to finish to have to use the function in the Page_load event:
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
'check whether page is postback or not
If Not Page.IsPostBack Then
VerifyAccessPage()
End If
End Sub

Answer 2

If your server is in a Windows Domain it should be connected to Active Directory, so by using windows authentication you already login with AD credentials (since the user has to be in the domain before, or it will be asked for AD credentials by the browser)
To get the user groups you could use the DirectorySearcher class, obviously when you