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Event Driven Programming

Sometimes a version control system and various tools are integrated to simplify the construction
of a GUI. Many modern IDEs also have a class browser, an object inspector, and a class hierarchy
diagram, for use with object-oriented software development.

1.1 Visual Basic

Visual Basic is a tool that allows you to develop Windows (Graphic User Interface - GUI)
applications. The applications have a familiar appearance to the user.Visual Basic is event-driven,
meaning code remains idle until called upon to respond to some event (button pressing, menu
selection, ). Visual Basic is governed by an event processor. Nothing happens until an event is
detected. Once an event is detected, the code corresponding to that event (event procedure) is
executed. Program control is then returned to the event processor.

Event?
Event Processor

Basic Basic Basic Event
Code Code Code Procedures
Figure 1.1: Event-driven.

1.2 Features of Visual Basic

Full set of objects - you ‘draw’ the application Lots of icons and pictures for your use Response
to mouse and keyboard actions clipboard and printer access full array of mathematical, string
handling, and graphics functions can handle fixed and dynamic variable and control arrays
sequential and random access file support useful debugger and error-handling facilities powerful
database access tools ActiveX support Package & Deployment Wizard makes distributing your
applications simple.
Visual Basic 6.0 Versus Other Versions of Visual Basic
The original Visual Basic for DOS and Visual Basic for Windows were introduced in 1991.
Visual Basic 3.0 (a vast improvement over previous versions) was released in 1993.
Visual Basic 4.0 released in late 1995 (added 32 bit application support).
Visual Basic 5.0 released in late 1996. New environment, supported creation of ActiveX controls,
deleted 16 bit application support.
Visual Basic 6.0 - some identified new features of Visual Basic 6.0
Faster compiler New ActiveX data control object allows database integration with wide variety
of applications New data report designer New Package & Deployment Wizard Additional internet
capabilities.
16 Bits Versus 32 Bits

Applications built using the Visual Basic 3.0 and the 16 bit version of Visual Basic 4.0 will run
under Windows 3.1, Windows for Workgroups, Windows NT, or Windows 95 Applications built
using the 32 bit version of Visual Basic 4.0, Visual Basic 5.0 and Visual Basic 6.0 will
only run with Windows 95 or Windows NT (Version 3.5.1 or higher). In this class, we will use

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