Programming Technologies

One way to provide users with a custom Microsoft Office solution is to develop and distribute an add-in. An add-in extends an Office application by adding functionality that is not in the core product. For example, an add-in might add new menu commands or toolbar buttons that display custom forms to add new features to an Office application.

If you are a frequent user of Microsoft Excel or Microsoft Access, you might already be familiar with some of the add-ins that these applications include. The Linked Table Manager in Access is an example of an add-in that uses Visual Basic for Applications (VBA). Many of the wizards that are available in other Office applications are also add-ins.

All Office 2000 applications support the new add-in architecture called COM add-ins that allows developers to create a single add-in that can run in any application. VBA developers can create COM add-ins by using Office 2000 Developer. COM add-ins can also be created by developers who are using one of the following programming languages:

• Microsoft Visual Basic versions 5.0 or later
• Microsoft Visual C++
• Microsoft Visual J++
• Any language that can create COM components

This wide support for COM add-ins means that developers can now use multiple development environments to create custom solutions in Office 2000. The only requirement to connect COM add-ins to an Office application is for the add-in to implement the IDExtensibility2 interface. COM add-ins can be loaded when the host application starts, or they can be loaded on demand. Support has also been added to allow the OnAction property of a custom command bar button to load a COM add-in.

See also

For more information about creating COM add-ins, see the Microsoft Office 2000/Visual Basic Programmer’s Guide.