Get TreeView Selected Node in SelectedIndexChanged event in ASP.Net

hi hope all you are fine i have a problem in treeview. I want to show treeview text by click node in next page. but it shows blank. here is my code

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        If Not IsPostBack Then
            tvSPLooping()
        End If

    End Sub

    Public Sub tvSPLooping()
        Dim cn As New SqlConnection
        Dim DA As SqlDataAdapter
        Dim Ds As New DataSet

        cn = New SqlConnection("Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\DynamicDB.mdf;Integrated Security=True;User Instance=True")
        cn.Open()

        Dim comm As SqlCommand = New SqlCommand("sptables", cn)
        comm.CommandType = CommandType.StoredProcedure

        DA = New SqlDataAdapter()
        DA.SelectCommand = comm
        Ds.Clear()
        DA.Fill(Ds)

        Dim prow, Crow, Grow As Integer
        Dim a As String

        prow = Ds.Tables(0).Rows.Count
        Crow = Ds.Tables(1).Rows.Count
        Grow = Ds.Tables(2).Rows.Count

        With TreeView4

            For i As Integer = 0 To prow - 1
                Dim node As TreeNode = New TreeNode(Ds.Tables(0).Rows(i)(0))
                .Nodes.Add(node)
                node.NavigateUrl = "~/Default.aspx"
            Next
            .CollapseAll()
        End With
    End Sub

    Protected Sub TreeView4_SelectedNodeChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles TreeView4.SelectedNodeChanged
        With TreeView4
            Session("TreeViewValue") = .SelectedNode.Text
        End With
    End Sub

Please Help thanks