no visibility of a new node

[curiousvbnet]

Hi, i have created a listview called listview1.
When a user cliks on an item he can see in the treeview2
-the parent terms of the item( each item is a different term)
-the name of the microthesaurus to which it belongs( microthesaurus is a semantic field ex : economy, history, geography etc...)


it is possible a term has two parents, in that case i can see in the treeview2 the term and its two parents like this

parent1
the term
microthesaurus1's name

parent2

the term
microthesaurus2' name


i have created a procedure to search the parent term of the selected term , called FindGenericTermes.
I can see the parent term of the selected term.
I have created another sub 'FindMicrothesaurus2' to find the microthesaurus of the term, [blue]but with this sub i can not see in the treeview2 the microthesaurus name [/blue].


Here is the code i use until now

Private Sub ListView1_ItemActivate(ByVal sender As Object, ByVal e As System.EventArgs) Handles ListView1.ItemActivate
        Dim iSelectedTermeID As Integer, strLibTerme As String, id_mt As Integer

        'déclaration de deux arrays qui vont contenir plusieurs lignes
        Dim drNAs() As DataRow, drSyns() As DataRow, drNA As DataRow, drSYN As DataRow
        Dim nNANode As TreeNode, nSynNode As TreeNode


               If Not ListView1.FocusedItem Is Nothing AndAlso Not ListView1.FocusedItem.Tag Is Nothing Then
                        ListView1.FocusedItem.ForeColor = SystemColors.HighlightText.Magenta
            iSelectedTermeID = CType(ListView1.FocusedItem.Tag, Integer)
            strLibTerme = ListView1.SelectedItems(0).Text

            ' 
            Dim matchingnodes As New Collection
           we search the node in the treeview1 first
            FindNode(iSelectedTermeID, TreeView1.Nodes, matchingnodes)
           
            Dim nbResults As Integer = matchingnodes.Count


            For Each nNode1 As TreeNode In matchingnodes
'we search the tag of the current microthesaurus

                               lib_mt_listitem_activate = GetMicroThesaurusForNode2(nNode1)
                MessageBox.Show(lib_mt_listitem_activate)

               



                               
                If Not nNode1 Is Nothing Then

                               With nNode1
                    .BackColor = SystemColors.Highlight.DeepSkyBlue
                    .ForeColor = SystemColors.HighlightText.MediumSlateBlue

                End With
                nNode1.ExpandAll()
                               
             [green]   'we create the node in treeview2 with the selected item in the listview1        [/green]       
                nNode2 = New TreeNode(strLibTerme)
                'TreeView2.Nodes.Add(nNode2)

                With nNode2
                    .BackColor = SystemColors.Highlight.DeepSkyBlue
                    .ForeColor = SystemColors.HighlightText.MediumSlateBlue
                    'on affecte l'icone vide au nouveau noeud crée
                    .ImageIndex = 3
                    .SelectedImageIndex = 3
                    ' on affecte à chaque terme du treeview2 le tag "GT" + ID_TERME
                    nNode2.Tag = "GT" & iSelectedTermeID.ToString
                End With


               
                [blue]this is the sub which causes problem[/blue]
               [red] FindMicrothesaurus2(lib_mt_listitem_activate, nNode2.Clone)[/red]
                FindGenericTermes(iSelectedTermeID, nNode2.Clone)
                TreeView2.ExpandAll()
                                TreeView2.SelectedNode = nNode2
            Next

        End If 'fin de If Not ListView1.FocusedItem Is Nothing AndAlso Not ListView1.FocusedItem.Tag Is Nothing Then
    End Sub

here is the findmicrothesaurus2 code

[blue]Private Sub FindMicrothesaurus2(ByVal TermeTag As String, ByRef nNode As TreeNode)[/blue]
        Dim drSelected_mt As DataRow()
        Dim nNewNode As TreeNode
        ' TermeTag is the  microthesaurus tag of the current node 

        'we need to find the microthesaurus label and for this we need the microthesaurus ID  
        
        Dim MT_ID As Integer
        MT_ID = Integer.Parse(TermeTag.Substring(2))

     [green]   drSelected_mt = objDS.Tables("MICRO_THESAURUS").Select("ID_MICRO_THESAURUS = " + MT_ID.ToString)[/green]
        If drSelected_mt.Length > 0 Then

            For Each drRow As DataRow In drSelected_mt
                nNewNode = New TreeNode("(MT) " & CType(drRow("Lib_MICRO_THESAURUS"), String))
                nNewNode.Tag = "MT" & CType(drRow("ID_MICRO_THESAURUS"), Integer).ToString
                nNewNode.ForeColor = SystemColors.Highlight.Maroon
                we add nNewNode to the nNode(it means nNode2 in our case)
                                
nNode.Nodes.add(nNewNode)                


            Next



        Else


                nNewNode = New TreeNode("(this term does not belong to a microthesaurus)")