GetDirectorySize - Calculate the size of a directory

' Returns the size of the specified directory
' - Note: requires Imports System.IO
' - Usage: Dim DirSize As Long = GetDirectorySize("D:\Projects")

Function GetDirectorySize(ByVal DirPath As String) As Long
  Dim DirSize As Long
  Dim Dir As DirectoryInfo = New DirectoryInfo(DirPath)

  ' add the size of each file
  Dim ChildFile As FileInfo
  For Each ChildFile In Dir.GetFiles()
    DirSize += ChildFile.Length
  Next

  ' add the size of each sub-directory, that is retrieved by recursively
  ' calling this same routine
  Dim SubDir As DirectoryInfo
  For Each SubDir In Dir.GetDirectories()
    DirSize += GetDirectorySize(SubDir.FullName)
  Next

  Return DirSize
End Function