The Property handler for an extension that originally had no handler is registered as follows:

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\PropertySystem\PropertyHandlers\.cs]
@="{D06391EE-2FEB-419B-9667-AD160D0849F3}"

The GUID specified by the default value of the key for the file extension is that of the registered property handler service, in this case our own. Note that there can be only one property handler for an extension.

If an original property handler is being extended, the registry entries look like this:

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\PropertySystem\PropertyHandlers\.bmp]
@="{D06391EE-2FEB-419B-9667-AD160D0849F3}"
"Chained"="{a38b883c-1682-497e-97b0-0a3a9e801682}"

Note the addition of the Chained value to the key. This is where File Meta stores the GUID of the original property handler.

Starting with version 1.5, on 64-bit systems, the same information, except that it references the GUID of the 32-bit version of the property handler, is also stored in the 32-bit section of the registry, so that 32-bit applications can also access File Meta properties. For example, the entry for an extended property handler looks like this:

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\PropertySystem\PropertyHandlers\.bmp]
@="{60211757-EF87-465e-B6C1-B37CF98295F9}"
"Chained"="{a38b883c-1682-497e-97b0-0a3a9e801682}"


Last edited Sep 29, 2016 at 10:22 AM by Dijji, version 5

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