Visual Basic Concepts
Introduction to Visual Basic Controls
The Visual Basic toolbox contains the tools you use to draw controls on your forms.
Figure 7.1 The Visual Basic toolbox
There are three broad categories of controls in Visual Basic:
Intrinsic controls, such as the command button and frame controls. These controls are contained inside the Visual Basic .exe file. Intrinsic controls are always included in the toolbox, unlike ActiveX controls and insertable objects, which can be removed from or added to the toolbox.
ActiveX controls, which exist as separate files with a .ocx file name extension. These include controls that are available in all editions of Visual Basic (DataCombo, DataList controls, and so on) and those that are available only in the Professional and Enterprise editions (such as Listview, Toolbar, Animation, and Tabbed Dialog). Many third-party ActiveX controls are also available.
Note Controls with the .vbx file name extension use older technology and are found in applications written in earlier versions of Visual Basic. When Visual Basic opens a project containing a .vbx control, the default behavior is to replace the .vbx control with an .ocx control, but only if an .ocx version of the control is available. See "Updating Older Versions of Visual Basic Controls" later in this chapter for information on updating controls to the .ocx format.
Insertable Objects, such as a Microsoft Excel Worksheet object containing a list of all your company's employees, or a Microsoft Project Calendar object containing the scheduling information for a project. Since these can be added to the toolbox, they can be considered controls. Some of these objects also support Automation (formerly called OLE Automation), which allows you to program another application's objects from within a Visual Basic application. See "Programming with Objects," for more information on Automation.
For More Information See "Using ActiveX Controls" in the Component Tools Guide for more information about the ActiveX controls available in the Professional and Enterprise versions of Visual Basic.