Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Dim Pfad As String = Application.ExecutablePath & "\Daten"
        ExpTree1.ShowTree(Pfad)
        'Label1.Text = Pfad
    End Sub

Public Sub ShowTree(ByVal Path As String)
    Dim nNode As TreeNode
    Dim di As New IO.DirectoryInfo(Path)
    If di.Exists Then
        nNode = New TreeNode(di.Name) With {.Tag = di}
        Me.Nodes.Add(nNode)
        Me.FillTreeNode(nNode)
    End If
End Sub

Private Sub FillTreeNode(ByVal dNode As TreeNode)
    Try
        Dim d As DirectoryInfo = CType(dNode.Tag, DirectoryInfo)
        For Each di As DirectoryInfo In d.GetDirectories
            Dim nNode As New TreeNode(di.Name) With {.Tag = di}
            dNode.Nodes.Add(nNode)
            nNode.Nodes.Add("")
        Next
    Catch : End Try
End Sub

<Runtime.InteropServices.DllImport("uxtheme.dll", _
  CharSet:=Runtime.InteropServices.CharSet.Unicode)>
Private Shared Function SetWindowTheme(hWnd As IntPtr, pszSubAppName As String, _
pszSubIdList As String) As Integer
End Function
 
Protected Overrides Sub CreateHandle()
    MyBase.CreateHandle()
    SetWindowTheme(Me.Handle, "explorer", Nothing)
End Sub

Private Sub FillTreeNode(ByVal dNode As TreeNode)
    Try
        Dim d As DirectoryInfo = CType(dNode.Tag, DirectoryInfo)
        For Each di As DirectoryInfo In d.GetDirectories
            Dim nNode As New TreeNode(di.Name) With {.Tag = di}
            dNode.Nodes.Add(nNode)
            Try
                If di.GetDirectories.Count > 0 Then
                    nNode.Nodes.Add("")
                End If
            Catch : End Try
        Next
    Catch : End Try
End Sub