Visual Basic for Applications (VBA) is an implementation of Microsoft's event-driven programming language Visual Basic 6.0 built into most desktop Microsoft Office applications. Although based on pre-.NET Visual Basic, which is no longer supported or updated by Microsoft, the VBA implementation in Office continues to be updated to support new Office features. VBA is used for professional and end-user development due to its perceived ease-of-use, Office's vast installed userbase, and extensive legacy in business.
Visual Basic for Applications enables building user-defined functions (UDFs), automating processes and accessing Windows API and other low-level functionality through dynamic-link libraries (DLLs). It supersedes and expands on the abilities of earlier application-specific macro programming languages such as Word's WordBASIC. It can be used to control many aspects of the host application, including manipulating user interface features, such as menus and toolbars, and working with custom user forms or dialog boxes.
As its name suggests, VBA is closely related to Visual Basic and uses the Visual Basic Runtime Library. However, VBA code normally can only run within a host application, rather than as a standalone program. VBA can, however, control one application from another using OLE Automation. For example, VBA can automatically create a Microsoft Word report from Microsoft Excel data that Excel collects automatically from polled sensors. VBA can use, but not create, ActiveX/COM DLLs, and later versions add support for class modules.
VBA is built into most Microsoft Office applications, including Office for Mac OS X (except version 2008), and other Microsoft applications, including Microsoft MapPoint and Microsoft Visio. VBA is also implemented, at least partially, in applications published by companies other than Microsoft, including ArcGIS, AutoCAD, CorelDraw, Kingsoft Office, LibreOffice, Reflection, SolidWorks, WordPerfect, and UNICOM System Architect (which supports VBA 7.1).
Посмотреть больше на Wikipedia.org