Private nodesCount As Integer, nodesID() As Integer, nodesParentID() As Integer, nodesText() As String, nodesTag() As Integer
    Public Sub FillTree(ByVal tree As TreeView)
        cnn.Open()
        Dim drTree As System.Data.SqlClient.SqlDataReader = New System.Data.SqlClient.SqlCommand("Select id, Parent_id, [Название] from T2 ORDER BY Название", cnn).ExecuteReader

        Do While drTree.Read
            ReDim Preserve nodesID(nodesCount) : nodesID(nodesCount) = CInt(drTree!ID)
            ReDim Preserve nodesParentID(nodesCount) : nodesParentID(nodesCount) = CInt(drTree!Parent_ID)
            ReDim Preserve nodesText(nodesCount) : nodesText(nodesCount) = CStr(drTree![Название])

            nodesCount += 1
        Loop
        drTree.Close()
        cnn.Close()
        tree.BeginUpdate()
        RecurTree(tree, Nothing, 0)
        tree.EndUpdate()

    End Sub

    Private Sub RecurTree(ByVal tree As System.Windows.Forms.TreeView, ByVal parentNode As System.Windows.Forms.TreeNode, ByVal parentID As Integer)
        For i As Integer = 0 To nodesCount - 1
            If nodesParentID(i) = parentID Then
                Dim tmpNode As New TreeNode(nodesText(i))
                RecurTree(tree, tmpNode, nodesID(i))
                If parentNode Is Nothing Then
                    tree.Nodes.Add(tmpNode)
                Else
                    parentNode.Nodes.Add(tmpNode)
                End If
            End If
        Next
    End Sub

TextBox6.Text = Me.TrV.SelectedNode.Text

TextBox3.Text = Me.TrV.SelectedNode.Name