This code is to check if a string is a valid GUID.
Source:
http://www.vbforums.com/showthread.php?447414-Solved-Check-if-string-is-Guid&p=2750956#post2750956
B4X:
Sub IsGuid(GUID As String) As Boolean
Return Regex.IsMatch("^(\{){0,1}[0-9a-fA-F]{8}\-" & _
"[0-9a-fA-F]{4}\-[0-9a-fA-F]{4}\-[0-9a-fA-F]{4}\-" & _
"[0-9a-fA-F]{12}(\}){0,1}$", GUID)
End Sub
Source:
http://www.vbforums.com/showthread.php?447414-Solved-Check-if-string-is-Guid&p=2750956#post2750956