#Region "BuildSiteMap"
    <MethodImpl(MethodImplOptions.Synchronized)> _
    Public Overrides Function BuildSiteMap() As SiteMapNode
        'Pulisco tutti i nodi della collezione (se ce ne sono)
        Clear()
        'Esco dal metodo se il nodo root non è nullo
        If Me.rootNode IsNot Nothing Then
            Return Me.rootNode
        End If

        'Creo il root node
        Me.rootNode = New SiteMapNode(Me, "0", "~/categorie.aspx", "HomePage", "HomePage")
        'AddNode(Me.rootNode, Nothing)


        Dim treeViewData As DataTable

        ' Get Menu table            
        Dim selectCommand As String = "SELECT ID_categorie, parent_categoria, nome_categoria FROM tab_categorie"
        Dim conString As String = ConfigurationManager.ConnectionStrings("connessione").ConnectionString
        Dim dad As New SqlDataAdapter(selectCommand, conString)
        Dim dtblDiscuss As New DataTable()
        dad.Fill(dtblDiscuss)

        treeViewData = dtblDiscuss


        Try
            Dim view As New DataView(treeViewData)
            view.RowFilter = "[parent_categoria] = 0"
            For Each row As DataRowView In view

                Dim childNode As New SiteMapNode(Me, row("ID_categorie").ToString(), Me.rootNode.Url & "?id=" & row("ID_categorie").ToString(), row("nome_categoria").ToString(), row("nome_categoria").ToString())

                AddNode(childNode, Me.rootNode)

                AddChildTreeViewNodes(treeViewData, childNode, row("ID_categorie"))

            Next

        Catch ex As Exception
            Throw New Exception(ex.Message, ex)
        End Try

        Return Me.rootNode

    End Function
#End Region

    Private Sub AddChildTreeViewNodes(treeViewData As DataTable, parentTreeViewNode As SiteMapNode, IDPadre As Integer)

        Try

            Dim view As New DataView(treeViewData)
            view.RowFilter = "[parent_categoria]=" & IDPadre
            For Each row As DataRowView In view

                Dim childNode2 As New SiteMapNode(Me, row("ID_categorie").ToString(), Me.rootNode.Url & "?id=" & row("ID_categorie").ToString(), row("nome_categoria").ToString(), row("nome_categoria").ToString())


                parentTreeViewNode.ChildNodes.Add(childNode2)

                AddChildTreeViewNodes(treeViewData, childNode2, row("ID_categorie"))

            Next


        Catch ex As Exception
            Throw New Exception(ex.Message, ex)
        End Try

    End Sub