I have a tree menu on the page that loads fine on the initial page load along with a dropdownlist that autopostback's with a new usertype. With that usertype I populate the tree again with the appropriate menu(well its suppose to), but it only runs the intial root level and doesn't fill in the rest.

<asp:DropDownList ID="roleDDL" AutoPostBack="true" runat="server">
            </asp:DropDownList><br />
            <div style="border:solid 0px #ff0000;background:#ffffff;color:#ffffff; width : 100%; height : 350px; overflow : auto; ">
            <asp:TreeView ID="TreeView3" ExpandDepth="FullyExpand" ShowCheckBoxes="All" RootNodeStyle-ImageUrl="~/images/computer.gif" ParentNodeStyle-ImageUrl="~/images/folder.gif" PopulateNodesFromClient="true" ShowLines="true" ShowExpandCollapse="false" runat="server">
                <NodeStyle Font-Names="Arial" Font-Size="8pt" ForeColor="DarkBlue" HorizontalPadding="5"/>
                <RootNodeStyle Font-Bold="True" Font-Size="9pt"/>
                <HoverNodeStyle Font-UnderLine="True" />
            </asp:TreeView>

  If Not Page.IsPostBack Then
                Buffer = True
                populateRoleDDL()
                PopulateRootLevel2()
                'Panel1.visible = False
                TreeView1.Visible = True
                TreeView3.Visible = True

End If

Private Sub PopulateRootLevel2()

        Dim dbConnection As New SqlConnection(ConfigurationManager.ConnectionStrings("LocalSqlServer").ConnectionString)
        'Dim myCommand As New SqlCommand("prcGetNodesByUserTypeID", dbConnection)
        Dim myCommand As New SqlCommand("select id,name,(select count(*) FROM tblNode WHERE parentid=sc.id) childnodecount FROM tblNode sc where parentID IS NULL", dbConnection)
        'myCommand.CommandType() = Data.CommandType.StoredProcedure
        'myCommand.Parameters.Add("@UserTypeID", SqlDbType.Int).Value = 1

        Dim da2 As New SqlDataAdapter(myCommand)
        Dim dt2 As New DataTable()
        da2.Fill(dt2)

        PopulateNodes2(dt2, TreeView3.Nodes)

        dbConnection.Close()
        myCommand.Dispose()

    End Sub

    Private Sub PopulateNodes2(ByVal dt2 As DataTable, ByVal nodes2 As TreeNodeCollection)

        For Each dr2 As DataRow In dt2.Rows
            Dim tn2 As New TreeNode()
            tn2.Text = dr2("Name").ToString()
            tn2.Value = dr2("ID").ToString()
            'tn2.NavigateUrl = "folderfilecleanup.aspx?gip=" & dr2("ID").ToString()
            tn2.SelectAction = TreeNodeSelectAction.None
            'tn2.Target = "menuSelectB"
            'tn.ShowCheckBox = True
            'tn.Checked = True
            tn2.Target = "_self"
            'tn2.SelectAction = TreeNodeSelectAction.Expand
            nodes2.Add(tn2)

            'If node has child nodes, then enable on-demand populating
            tn2.PopulateOnDemand = (CInt(dr2("childnodecount")) > 0)
        Next

    End Sub

    Private Sub PopulateSubLevel2(ByVal parentid2 As Integer, ByVal parentNode2 As TreeNode)

        Dim tempUserTypeID As Integer
        tempUserTypeID = 1

        Dim dbConnection As New SqlConnection(ConfigurationManager.ConnectionStrings("LocalSqlServer").ConnectionString)
        'Dim objCommand As New SqlCommand("select id,name,(select count(*) FROM tblNode WHERE parentid=sc.id) childnodecount FROM tblNode sc JOIN where parentID=@parentID and ", dbConnection)
        Dim objCommand As New SqlCommand("select sc.id,sc.name,(select count(*) FROM tblNode tan WHERE tan.parentid=sc.id) childnodecount FROM tblNode sc JOIN tblNodeUserType tut ON tut.NodeID = sc.ID WHERE sc.parentID=@parentID and tut.UserTypeID = @UserTypeID and sc.Active=1", dbConnection)
        objCommand.Parameters.Add("@parentID", SqlDbType.Int).Value = parentid2
        'If roleDDL.SelectedValue = "Choose a Type" Then
        '    objCommand.Parameters.Add("@UserTypeID", SqlDbType.Int).Value = 0
        'Else
        '    objCommand.Parameters.Add("@UserTypeID", SqlDbType.Int).Value = Session("usertypeid") 'roleDDL.SelectedValue
        'End If

        objCommand.Parameters.Add("@UserTypeID", SqlDbType.Int).Value = roleDDL.SelectedValue ' Session("usertypeid")

        Dim da2 As New SqlDataAdapter(objCommand)
        Dim dt2 As New DataTable()
        da2.Fill(dt2)
        PopulateNodes2(dt2, parentNode2.ChildNodes)

    End Sub

    Private Sub TreeView3_TreeNodePopulate(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.TreeNodeEventArgs) Handles TreeView3.TreeNodePopulate

        PopulateSubLevel2(CInt(e.Node.Value), e.Node)

    End Sub

 Protected Sub roleDDL_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles roleDDL.SelectedIndexChanged
        TreeView3.Nodes.Clear()
        PopulateRootLevel2()
    End Sub

The code in If Not Page.IsPostBack Then statement will not be executed when the page is postback by the dropdownlist's postback.