Using Win32 functions in Visual FoxPro Image Gallery
Code examples:
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Capturing keyboard activity of another application with the Raw Input API (VFP9)
How to change display settings: screen resolution, screen refresh rate
Enumerating raw input devices attached to the system (keyboard, mouse, human interface device)
Displaying dimmed window behind VFP top-level form
How to display Windows On-Screen Keyboard
How to control Adobe Reader 9.0 (SDI mode) from VFP application
Reading and setting explicit Application User Model ID for the current process (Win7)
Switching between keyboard layouts
GDI+: Creating thumbnails to preview images in a directory
Finding out if the current user is the Guest account
GDI+: creating a gradient
Using EnumPrinters function to enumerate locally installed printers
Displaying Windows shell folders in TreeView control with Visual FoxPro FLL
Browsing Windows Known Folders (Special Folders)
Detecting changes in connections to removable drives (VFP9)
Displaying hypertext links with the SysLink control (VFP9, Comctl32.dll)
Reading and setting system access privileges for the current process
Customizing the frame of top-level form: removing the standard frame (VFP9, Vista)
How to register custom Event Log source
How to generate GUID values

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Before you begin:
The result is returned in a format like that of the following sample:
{557cf400-1a04-11d3-9a73-0000f81ef32e}

See also:
  • Generating random UUID values
  • Generating sequential UUID values

  • DO declare
    
    LOCAL cGUID, cGUIDString, cGUID1
    cGUID = REPLICATE(CHR(0), 16)  && 128 bits
    
    IF CoCreateGuid(@cGUID) = 0
        cGUIDString = StringFromGUID(cGUID)
        ? cGUID
        ? cGUIDString
    
        * converting from String back to GUID
        cGUID1 = REPLICATE(CHR(0), 16)
        = CLSIDFromString(STRCONV(cGUIDString,5), @cGUID1)
        ? cGUID1
    ENDIF
    * end of main
    
    FUNCTION StringFromGUID(cGUID)
        LOCAL cBuffer, nBufsize
        nBufsize=128
        cBuffer = REPLICATE(CHR(0), nBufsize*2)
        = StringFromGUID2(cGUID, @cBuffer, nBufsize)
        cBuffer = SUBSTR(cBuffer, 1, AT(CHR(0)+CHR(0), cBuffer))
    RETURN STRCONV(cBuffer, 6)
    
    PROCEDURE declare
        DECLARE INTEGER CoCreateGuid IN ole32 STRING @pguid
    
        DECLARE INTEGER CLSIDFromString IN ole32;
            STRING lpsz, STRING @pclsid
    
        DECLARE INTEGER StringFromGUID2 IN ole32;
            STRING rguid, STRING @lpsz, INTEGER cchMax
    
    

    User rating: 9/10 (1 votes)
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    844 bytes  
    Created: 2004-07-15 13:24:36  
    Modified: 2013-10-01 12:23:16  
    Visits in 7 days: 44  
    Listed functions:
    CLSIDFromString
    CoCreateGuid
    StringFromGUID2
    Printer friendly API declarations
    My comment:
    The GUID is a unique 128-bit integer used for CLSIDs and interface identifiers.

    See also Microsoft Knowledge Base Article 269387 How To Obtain a GUID in Visual FoxPro

    * * *
    Having a connection to SQL Server, Guids can be generated with the NewId() function.
    FUNCTION NewGuid() As String
            IF SQLEXEC(1, "SELECT NewId() As guid", "csGuid") > 0
                    RETURN csGuid.guid
            ELSE
                    RETURN NULL
            ENDIF

    Another way is using the Scriptlet.TypeLib COM. Note that you must create a new instance of the class for each Guid to be generated, which probably produces some overhead.
    obj = CreateObject("Scriptlet.TypeLib")
    ? SUBSTR(obj.GUID,2,36)

    After a simple test I can estimate that the COM procedure is 5 to 10% faster than the SQL one (local server); and API is the winner creating GUID 15-20 times faster than COM -- for example, 0.24 seconds versus 4 seconds per 10,000 guids created.

    On the same computer C# code generated 1,000,000 guids in 1.05 seconds.
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    User Contributed Notes:
    A.M. | 2006-07-19 15:38:05
    DECLARE INTEGER UuidCreate IN rpcrt4 STRING @UUID

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