Visual Basic Codes
Visual Basic > API and Miscellaneous sample source codes

To convert a Class ID to a prog ID and back use the following routines

To convert a Class ID to a prog ID and back use the following routines
Note, a demonstration routine can be found at the bottom of this post:

Private Declare Function ProgIDFromCLSID Lib "ole32.dll" (CLSID As Any, lProgID As Long) As Long
Private Declare Function CLSIDFromString Lib "ole32.dll" (ByVal lProgID As Long, CLSID As Any) As Long
Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (vDest As Any, vSource As Any, ByVal lBytes As Long)
Private Declare Function CLSIDFromProgID Lib "ole32.dll" (ByVal lpszProgID As Long, pCLSID As Any) As Long
Private Declare Function StringFromCLSID Lib "ole32.dll" (pCLSID As Any, lpszProgID As Long) As Long
Private Declare Sub CoTaskMemFree Lib "ole32.dll" (ByVal pv As Long)

'Purpose     :  Converts a string Class ID (inc. braces) into as string Prog ID
'Inputs      :  sCLSID                  The Class ID to find the Prog ID of.
'Outputs     :  Returns the Prog ID as a string
'Notes       :
'Revisions   :

Function CLSIDToProgID(ByVal sCLSID As String) As String
    Dim lFirstChar As Long, lLastChar As Long, iChar As Integer
    Dim abGuid(15) As Byte

    'Convert string to a binary
    CLSIDFromString StrPtr(sCLSID), abGuid(0)
    'Convert to a string and get pointer to result
    ProgIDFromCLSID abGuid(0), lFirstChar
    lLastChar = lFirstChar
    'Find end of string
    Do
        CopyMemory iChar, ByVal lLastChar, 2
        If iChar Then
            lLastChar = lLastChar + 2
        End If
    Loop While iChar
    CLSIDToProgID = Space$((lLastChar - lFirstChar) \ 2)
    CopyMemory ByVal StrPtr(CLSIDToProgID), ByVal lFirstChar, (lLastChar - lFirstChar)
End Function


'Purpose     :  Converts a string Prog ID (inc. braces) into as string Class ID
'Inputs      :  sProgID                 The Prog ID to find the Class ID of.
'Outputs     :  Returns the Class ID as a string
'Notes       :
'Revisions   :

Function ProgIDToCLSID(ByVal sProgID As String) As String
    Dim lFirstChar As Long, lLastChar As Long
    Dim iChar As Integer
    Dim abGuid(15) As Byte
    
    'Get CLSID
    CLSIDFromProgID StrPtr(sProgID), abGuid(0)
    'Convert to a string and get pointer to result
    StringFromCLSID abGuid(0), lFirstChar

    'Find end of string
    lLastChar = lFirstChar
    Do
        CopyMemory iChar, ByVal lLastChar, 2
        If iChar Then
            lLastChar = lLastChar + 2
        End If
    Loop While iChar
    
    ProgIDToCLSID = Space$((lLastChar - lFirstChar) \ 2)
    CopyMemory ByVal StrPtr(ProgIDToCLSID), ByVal lFirstChar, (lLastChar - lFirstChar)
End Function


'Demonstration routine
Sub Test()
    Dim sProgID
    'Get the Prog ID for Excel
    sProgID = CLSIDToProgID("{00024500-0000-0000-C000-000000000046}")
    Debug.Print sProgID
    'Get the Class ID for Excel (as above)
    Debug.Print ProgIDToCLSID(sProgID)
End Sub