This project shows you how to write an addin for Visual Studio 2005. Read the documentation well! There are some crucial steps needed to get the add-in registred.

http://www.codeproject.com/useritems/LineCounterAddin.asp


Dont forget!:

// Only execute the startup code if the connection mode is a startup mode
if (connectMode == ext_ConnectMode.ext_cm_AfterStartup connectMode == ext_ConnectMode.ext_cm_Startup)

The project itself didnt work as expected but I could use lots of bits and pieces for my own addin. For your information, im working on an addin which can repair relation graphics in the classdesigner. The out of the box version is a pain in the @$$