Chapter 3

Intrinsic Controls

In Microsoft Visual Basic jargon, intrinsic controls (or built-in controls) are those controls visible in the Toolbox window when you launch the environment. This important group includes controls, such as Label, TFextbox, and CommandButton controls, that are used in nearly every application. As you know, Visual Basic can be extended using additional Microsoft ActiveX Controls (formerly known as OCX controls, or OLE custom controls) either provided in the Visual Basic package or available as commercial, shareware, or even freeware third-party products. Even if such external controls are often more powerful than built-in controls, intrinsic controls have a few advantages that you should always take into account:

Support for intrinsic controls is included in the MSVBVM60.DLL, the runtime file that's distributed with every Visual Basic application. This means that if a program exclusively uses intrinsic controls, you don't need to distribute any additional OCX files, which greatly simplifies the installation process and reduces disk requirements.

In general, Visual Basic can create and display intrinsic controls faster than it can external ActiveX controls because the code for their management is already in the Visual Basic runtime module and doesn't have to be loaded when a form references an intrinsic control for the first time. Also, applications based on intrinsic controls usually perform faster on machines with less memory; no extra memory is needed by additional OCX modules.

Because programs based exclusively on intrinsic controls require fewer ancillary files, they can be downloaded faster through the Internet. Moreover, if end users previously installed any other Visual Basic application, Visual Basic runtime files are already installed on the target machine, which reduces download times to the minimum.

For all these reasons, it's important to learn how to make the best of intrinsic controls. In this chapter, I focus on their most important properties, methods, and events, and I also show how to address some common programming issues using intrinsic controls exclusively.