Andrea Bertolotto's Website

For a background intro to Addin technology and Visual Studio automation, take a look at this article: Custom Add-Ins Help You Maximize the Productivity of Visual Studio .NET. This is, in my opinion, one of the most complete ones (even if it was on Visual Studio 2002).

Some things have changed with new Visual Studio versions, but the basic ideas are the same.

I tried to learn about many aspects of addin creation experimenting with my addin, so I hope having a look at code and projects is in some way useful.

First of all addin comes in two flavours: version 1.3 targetting Visual Studio 2003 and version 2.0 targetting Visual Studio 2005.

Addin functionality is the same between versions, and so is internal implementation. Anyway there are many differences between two IDEs:
- how to add named commands to Visual Studio menus (now implementation is a lot easier and allows automatically to contemplate localized Visual Studio versions)
- addins are binded and configured in Visual Studio 2003 using registry options (so Setup Project should take care of it); in Visual Studio 2005 adding an addin is done using XML configuration file
- same as previous is regarding creating addin option page (registry keys vs xml files)
- adding a custom icon to menu now can be done creating a managed resource file, instead of a basic windows resource file (and now Visual Studio 2005 supports high-color icons)
At last Visual Studio 2005 seems to be a fantastic step ahead from previous version.

These are addin functionalities:
- Check if a banner is already present at top of source code file (active document in IDE) - supported languages are C# and VB
- If banner is not available, adds a standard copyright message and puts developer and creation date on banner
- If banner is already there, asks a comment/message to user and appends it, with current date, to banner
- All messages are customizable using option form: in Visual Studio 2005 use Tools | Options... | Sharp Add-Ins; in Visual Studio 2003 use Tools | Options... | Add History Banner AddIn
- Banner comments length can be customized with max length. If comment length exceeds max, string will be splitted at last word
- Comment adding in banner is considered atomic operation - so it can be undone using a single Undo action
- Addin operation is available through Edit Menu and through keyboard shortcut - ALT+L, ALT+H (Keep in mind changing keyboard shortcut on Visual Studio 2003 requires a writable "Keyboard mapping scheme" - usually simply copy default one or you'll get a message during addin loading)
- Editing point is not changed when adding comments, so you can add history and continue working, without suffering page moves
- Either projects contain custom icons for menu item, custom about box and fully working setup projects

Last note should be about adding and using customized resources in addins.
You will find in each project custom external DLL with source and icons to understand the process.
In Visual Studio 2003 you must create icons - keep in mind particular color in palette indicating transparency - and embed them in a simple DLL.
I accomplished this task using this tool: Resource Hacker by Angus Johnson.
Resource ID is then referred when adding new menu item to Visual Studio.
In Visual Studio 2005 things are easier, you simply need to create a managed resources DLL embedding custom icon. Batch script is included showing this technique.

One of the biggest source of tricks and code about Visual Studio Addins is: Craig Skibo's WebLog.