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Add-ins are programs that add optional commands and features to Microsoft Excel. For example, the Analysis ToolPak add-in program (add-in: A supplemental program that adds custom commands or custom features to Microsoft Office.) provides a set of data analysis tools that can save steps when you develop complex statistical or engineering analyses.
Excel has three types of add-in programs: Excel add-ins, custom Component Object Model (COM) add-ins (COM add-in: A supplemental program that extends the capabilities of a Microsoft Office program by adding custom commands and specialized features. COM add-ins can run in one or more Office programs. COM add-ins use the file name extension .dll or .exe.), and automation add-ins.
Where to get add-ins A set of add-ins is available when you install Excel, and more add-ins are available from the Microsoft Office Web site.
Installing add-ins on your computer Before you can use an add-in, you must first install it on your computer and then load it into Excel. Add-ins (*.xla files) are installed by default in one of the following places:
- The Library folder or one of its subfolders in the Microsoft Office/Office folder.
- The Documents and Settings/<user name>/Application Data/Microsoft/AddIns folder.
The administrator for your company's network can designate other locations for add-in programs. See your administrator for more information.
Loading add-ins into Excel After installing an add-in, you must load it into Excel. Loading an add-in makes the feature available in Excel and adds any associated commands to the appropriate menus.
Unloading add-ins from Excel To conserve memory and improve performance, unload add-ins you don't use often. Unloading an add-in removes its features and commands from Excel, but the add-in program remains on your computer so you can easily reload it. When you unload an add-in program, it remains in memory until you restart Excel.
Designing custom Excel add-ins You can use your own Visual Basic (Visual Basic: A high-level, visual-programming version of Basic. Visual Basic was developed by Microsoft for building Windows-based applications.) programs as custom add-ins. For information about making a Visual Basic program an add-in, see the Microsoft Office XP Developer's Guide, which you can obtain from Microsoft.
Automation add-ins allow COM automation functions to be called from a worksheet.
Using automation add-ins The developer of an automation add-in usually provides installation and removal programs for the add-in. Contact the person who provided the add-in to you for instructions on how to install and use it. Automation add-ins that have been registered on the system can be accessed through the Tools menu.