MAPI Custom Controls and the CDO Library

Although both the MAPI custom controls and the CDO Library are designed for Visual Basic programmers, they represent significantly different capabilities.

A control is a user interface element that enables you to display data for the user. The custom controls are usually convenient for offering more specialized capabilities than are provided by the standard user interface controls such as the list box, combo box, command button, and option button.

A programmable object may offer some user interface capabilities, but that is usually not its primary purpose. It offers the very powerful ability to interact with existing OLE objects. For a familiar example, consider the data access objects provided with Microsoft Visual Basic version 3.0 Professional Edition and subsequent versions. The data access library lets you create and use such database objects as tables and queries. As the data access library lets you use database objects, the CDO Library lets you add messaging to your applications.