How can I Get Sum Total Size of Directories Which Listed in ListBox?

[.paul.]

Works fine for me...

ListBox1.Items.AddRange(IO.Directory.GetDirectories("Z:\Documents"))
Dim dirSize As Long = ListBox1.Items.Cast(Of String).Sum(Function(s) (From strFile In My.Computer.FileSystem.GetFiles(s, FileIO.SearchOption.SearchAllSubDirectories) Select New IO.FileInfo(strFile).Length).Sum())
MsgBox(((dirSize / 1024) / 1024) / 1024)