Session Variables aren't retrieved during Postback

[royster]

Hi I have a web page, which has a login corner. When someone logs in and clicks the "Go" button, a class called Security gathers the users details and posts it back to the same page, under a session variable called "User"

Private Sub cmdLogin_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdLogin.Click
        'Login into the system
        Dim l As New Security()
        Dim Outcome As PPPL.Security.LoginOutcome
 
        Outcome = l.DoLogin(Login.Text, Password.Text)
        Select Case Outcome
            Case Security.LoginOutcome.lgBADLOGIN
            Case Security.LoginOutcome.lgBADPASSWORD
            Case Security.LoginOutcome.lgINACTIVE
            Case Security.LoginOutcome.lgLOCKED
            Case Security.LoginOutcome.lgLOGGEDIN
                Session("User") = l
                If l.IsAdmin Then
                    EnableFixtureEntry(True)
                Else
                    EnableFixtureEntry(False)
                End If
                Label3.Text = "You are logged in as " & l.User
        End Select
 
    End Sub

When the page postsback to itself, I need that session variable saved, so that I can access it. Trouble is when I try to retrieve it, I get a null value.

Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        'Put user code to initialize the page here
 
        If IsPostBack Then
            'Determine if the user is logged in.
            Dim l As New Security()
            l = Session("User")
 
            If Not l Is Nothing Then
                pnlPredictions.Controls.Add(New LiteralControl(l.User))
            End If
        End If
 
    End Sub

Problem is that when it gets to evaluating whether l Is Nothing, it always returns true. Please can someone help me?