Creating A Unique Indentifier With A GUID
This page describes how to create a globally unique indentifier.
If you need a unique identifier that is certain to be unique across all applications and
all computers and all users, you can create a "Globally Unique Indentifier", or GUID. This
identifier is universally unqiue. Note that while this value will be unique, there is no meaningful
information contained within it. That is, you cannot examine the value of a GUID and discern any
information about when or where it was created. The code for creating a GUID is shown below:
Private Declare Function CoCreateGuid Lib "OLE32.DLL" (pGuid As GUID) As Long
Private Type GUID
Data1 As Long
Data2 As Integer
Data3 As Integer
Data4(0 To 7) As Byte
End Type
Public Function CreateGUID() As String
Dim G As GUID
With G
If (CoCreateGuid(G) = 0) Then
CreateGUID = _
String$(8 - Len(Hex$(.Data1)), "0") & Hex$(.Data1) & _
String$(4 - Len(Hex$(.Data2)), "0") & Hex$(.Data2) & _
String$(4 - Len(Hex$(.Data3)), "0") & Hex$(.Data3) & _
IIf((.Data4(0) < &H10), "0", "") & Hex$(.Data4(0)) & _
IIf((.Data4(1) < &H10), "0", "") & Hex$(.Data4(1)) & _
IIf((.Data4(2) < &H10), "0", "") & Hex$(.Data4(2)) & _
IIf((.Data4(3) < &H10), "0", "") & Hex$(.Data4(3)) & _
IIf((.Data4(4) < &H10), "0", "") & Hex$(.Data4(4)) & _
IIf((.Data4(5) < &H10), "0", "") & Hex$(.Data4(5)) & _
IIf((.Data4(6) < &H10), "0", "") & Hex$(.Data4(6)) & _
IIf((.Data4(7) < &H10), "0", "") & Hex$(.Data4(7))
End If
End With
End Function
You can then call this function with code like:
Dim UniqueID As String
UniqueID = CreateGUID()
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This page last updated: 20-March-2009. |