Dim ss() As String = {"aa-2016-1000","bb-2013-001","cc-204-003"}
Dim v As Integer
Dim max As Integer
For Each s As String In ss
Dim vs As String = s.SubString(s.LastIndexOf("-")+1)
If Integer.TryParse(vs,v)
If v > max Then
max = v
End If
End If
Next
Return max
http://www.foxtable.com/webhelp/scr/1338.htm
http://www.foxtable.com/webhelp/scr/0324.htm