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Visual Basic Concepts

Component Basics

A software component created with Microsoft Visual Basic is a file containing executable code — an .exe, .dll, or .ocx file — that provides objects other applications and components can use.

An application or component that uses objects provided by other software components is referred to as a client. A client uses the services of a software component by creating instances of classes the component provides, and calling their properties and methods.

In earlier versions of Visual Basic, you could create components called OLE servers. The features of components created with Visual Basic are greatly expanded, including the ability to raise events, improved support for asynchronous callbacks, and the ability to provide ActiveX controls and documents.

The following topics provide key definitions and concepts you should be aware of when developing any software component using Visual Basic.

For More Information   The core information on creating OLE servers, referred to as code components, includes "Creating an ActiveX DLL," "Creating an ActiveX EXE Component," "General Principles of Component Design," "Debugging, Testing, and Deploying Components," "Building Code Components," and "ActiveX Component Standards and Guidelines."