OK, there seems to be a site bug which is corrupting the VB code.
Let's see if we can get it readable:
Private Shared chars As String = "abcdefghijklmnopqrstuvwxyz0123456789"
Private random As New Random()
Private Function RandomString(size As Integer) As String
Return New String(Enumerable.Repeat(chars, size). [Select]
(Function(s) s( random. [Next]
(s.Length))) .ToArray())
End Function
Assemble the bits into a single line!