The Excel-DNA IntelliSense extension will attempt to find registration info for any .xll add-in loaded. Discovery of the registration info is by calling a hidden function called "RegistrationInfo_<XllGuid>", where "<XllGuid>" is a guid computed from the full path of the xll. This project shows how to compute this Guid.
The Guid assocated with the xll is computed as the version 5 (SHA1) UUID (in accordance with section 4.3 of RFC 4122) using:
- the special Excel-DNA name space ID 306D016E-CCE8-4861-9DA1-51A27CBE341A,
- the SHA-1 hash algorithm of the full path of the xll, converted to upper-case and UTF-8 encoding.
An implementation of the Guid calculation in C# is included in Excel-DNA.
This project provides a small C program that computes the same Guid.
As a test, the path "C:\Temp\Test.xll" should evaluate to the Guid string: f3fe5a6e63fc5c18b9bb5ae7b3d12632.
The registration function for the add-in "C:\Temp\Test.xll" will thus be called "RegistrationInfo_f3fe5a6e63fc5c18b9bb5ae7b3d12632".
The RegistrationInfo function should be registered with type "QQ", and may be a hidden function.
The parameter is interpreted as a version number. To allow polling, we return as the first row a (double) version which can be passed to short-circuit the call if nothing has changed.
The RegistrationInfo function should check the first parameter - if it is the same as the last returned version, the RegistrationInfo function can return null (xlEmpty?).
Otherwise the IntelliSense extension expects an array with 255 columns, one row for the version and one row for each function. The first row should contain:
- the full path to the xll, and
- the info version number.
Every registration row should contain exactly the information passed to the xlfRegister function.
Any missing entries in the array should be returned as xlEmpty.
The original GuidUtility code used in Excel-DNA to generate the version 5 Guid is from https://github.com/LogosBible/Logos.Utility/blob/master/src/Logos.Utility/GuidUtility.cs
The SHA-1 code in this project is from https://www.packetizer.com/security/sha1/