Visual Basic.NET - calcular tamaño de un directorio

ola, alguien sabe como calcular el tamaño de un directorio?¿
gracias

Aqui tienes 2 maneras de hacerlo.....

' 1:
Dim filespec As String = "C:\Security"
Dim fso, f, s
Private Sub BtnDirectoryInfo_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnDirectoryInfo.Click
fso = CreateObject("Scripting.FileSystemObject")
f = fso.Getfolder(filespec)
s = "Tamaño: " & (CInt(f.size) / 1024)
MessageBox.Show(s)
End Sub

'2:
Imports System.IO

Dim infdir As System.IO.DirectoryInfo

Private Sub BtnDirectoryInfo_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnDirectoryInfo.Click
infdir = New DirectoryInfo(filespec)
MessageBox.Show(infdir.Attributes
End Sub

Public Shared Function DirSize(ByVal d As DirectoryInfo) As Long
Dim Size As Long = 0
' Add file sizes.
Dim fis As FileInfo() = d.GetFiles()
Dim fi As FileInfo
For Each fi In fis
Size += fi.Length
Next fi
' Add subdirectory sizes.
Dim dis As DirectoryInfo() = d.GetDirectories()
Dim di As DirectoryInfo
For Each di In dis
Size += DirSize(di)
Next di
Return Size
End Function 'DirSize