Cargar la estructura de arbol del disco en un TreeView

Imports System
Imports System.IO
Imports System.Windows.Forms
 
  '...
 
  Private Sub Explorer(ByVal node As TreeNode)
     Try
       Dim s As String
       node.Nodes.Clear() 
         For Each s In Directory.GetDirectories(node.FullPath)
           node.Nodes.Add(Path.GetFileName(s))
         Next
     Catch
     End Try
  End Sub
 
  Private Sub BTNClick(ByVal sender As Object, ByVal e As EventArgs)
     TV.Nodes.Add("C:\")
     Explorer(TV.Nodes.Item(0))
  End Sub
 
  Private Sub TVAfterExpand(ByVal sender As Object, ByVal e As TreeViewEventArgs)
     Dim tn As TreeNode
     For Each tn In e.Node.Nodes
        Explorer(tn)
     Next 
  End Sub