What Is a COM Add-in?

This content is no longer actively maintained. It is provided as is, for anyone who may still be using these technologies, with no warranties or claims of accuracy with regard to the most recent product version or service release.

COM add-ins are an exciting addition to Office 2000. You can create a single COM add-in that's available to any of the Office applications - Word, Excel, Access, PowerPoint, Outlook, or FrontPage. You can also create add-ins for the Visual Basic Editor. By building COM add-ins, you can extend the functionality of your Office-based applications without adding complexity for the user.

A COM add-in is a dynamic-link library (DLL) that is specially registered so that it can be loaded by the Office 2000 applications. You can build COM add-ins with Microsoft Visual Basic version 5.0 or later, or any of the Office 2000 applications in Microsoft Office 2000 Developer. You can also create COM add-ins with Microsoft Visual C++ or Microsoft Visual J++. A discussion of these tools is beyond the scope of this book; for more information about them, see the Microsoft Developer Network Web site at http://msdn.microsoft.com.

Note   A COM add-in can also be an ActiveX .exe file. This chapter focuses on creating COM add-ins as DLLs because they generally provide better performance than .exe files do.