Before we begin Visual Basic 6 programming, let us understand some basic concepts of programming. According to Webopedia, a computer program is an organized list of instructions that, when executed, causes the computer to behave in a predetermined manner. Without programs, computers are useless. Therefore, programming means designing or creating a set of instructions to ask the computer to carry out certain jobs which normally are very much faster than human beings can do.
Many people think that computer is very intelligent, but in actual fact it is dumb and can't do anything without human assistance. The microchips of a CPU can only understand two distinct electrical states, namely, the on and off states, or 0 and 1 in the binary system. So, the CPU only understands a combinations of 0 and 1 code, a language which we called machine language. Machine language is extremely difficult to learn and it is not for us to master it easily. That's why modern programming languages supported by web hosting providers, such as PHP, Javascript, etc are all very high level. They allow us to communicate with the computer using language we can relate to, rather than machine language.
Fortunately , we have many smart programmers who wrote interpreters and compilers that can translate human language-like programs such as BASIC into machine language so that the computer can carry out the instructions entered by the users. Machine language is known as the primitive language while Interpreters and compilers like Visual Basic are called high-level language. Some of the high level computer languages beside Visual Basic are Fortran, Cobol, Java, C, C++, Turbo Pascal, flash action script, JavaScript, HTML and more.
1.2 What is Visual Basic?
VISUAL BASIC is a high level programming language which evolved from the earlier DOS version called BASIC. BASIC means Beginners' All-purpose Symbolic Instruction Code. It is a relatively easy programming language to learn. The code looks a lot like English Language. Different software companies produced different versions of BASIC, such as Microsoft QBASIC, QUICKBASIC, GWBASIC ,IBM BASICA and so on. However, people prefer to use Microsoft Visual Basic today, as it is a well developed programming language and supporting resources are available everywhere. Now, there are many versions of VB exist in the market, the most popular one and still widely used by many VB programmers is none other than Visual Basic 6 . We also have VB.net, Visual Basic 2005, Visual Basic 2008 and the latest Visual Basic 2010 . Both Vb2008 and VB2010 are fully object oriented programming (OOP) languages.
VISUAL BASIC is a VISUAL and Event-driven Programming Language. These are the main divergence from the old BASIC. In BASIC, programming is done in a text-only environment and the program is executed sequentially. In VB6, programming is done in a graphical environment. In the old BASIC, you have to write program code for each graphical object you wish to display it on screen, including its position and its color. However, In VB6 , you just need to drag and drop any graphical object anywhere on the form, and you can change its properties using the properties window.
In addition, Visual Basic 6 is Event-driven because we need to write code in order to perform some tasks in response to certain events. The events usually comprises but not limited to the user's inputs. Some of the events are load, click, double click, drag and drop, pressing the keys and more. We will learn more about events in later lessons. Therefore, a VB6 Program is made up of many subprograms, each has its own program code, and each can be executed independently and at the same time each can be linked together in one way or another.
1.3 What programs can you create with Visual Basic 6?
With VB 6, you can create any program depending on your objective. For example, if you are a college or university lecturer, you can create educational programs to teach business, mathematics, science, economics, engineering, computer science, accountancy , financial management, information system and more to make teaching more effective and interesting. For example, you can create mathematical programs such as Geometric Progression, Quadratic Equation Solver, Simultaneous Equation Solver ,Prime Number, Factors Finder, Quadratic Function Graph Plotter and so on. For science teacher, you can create simulation programs such as Projectile, Simple Harmonic Motion, Star War etc. If you are in business, you can also create business programs such as inventory management system , Amortization Calculator , investments calculator, point-of-sale system, payroll system, accounting program and more to help manage your business and increase productivity. For those of you who like games , you can create those programs such as slot machine, reversi, tic tac toe and more. Besides, you can create multimedia programs such as Smart Audio Player, Multimedia Player and so on. Indeed, there is no limit to what program you can create ! There are many such programs in this tutorial, so you must spend more time on the tutorial in order to learn how to create those programs.
1.4 The Visual Basic 6 Integrated Development Environment
Before you can program in VB 6, you need to install Visual Basic 6 compiler in your computer. You can purchase a copy of Microsoft Visual Basic 6.0 Learning Edition or Microsoft Visual Basic Professional 6.0 with Plus Pack from Amazon.com, both are vb6 compilers. If you have already installed Microsoft Office in your PC or laptop, you can also use the built-in Visual Basic Application in Excel to start creating Visual Basic programs without having to spend extra cash to buy the VB6 compiler.
After installing vb6 compiler, the icon with appear on your desktop or in your programs menu. Click on the icon to launch the VB6 compiler. On start up, Visual Basic 6.0 will display the following dialog box as shown in Figure 1.1.
Figure 1.1: New Project Dialog
You can choose to either start a new project, open an existing project or select a list of recently opened programs. A project is a collection of files that make up your application. There are various types of applications that we could create, however, we shall concentrate on creating Standard EXE programs (EXE means executable). Before you begin, you must think of an application that might be useful, have commercial values . educational or recreational. click on the Standard EXE icon to go into the actual Visual Basic 6 programming environment.
When you start a new Visual Basic 6 Standard EXE project, you will be presented with the Visual Basic 6 Integrated Development Environment (IDE). The Visual Basic 6 Integrated Programming Environment is show in Figure 1.2. It consists of the toolbox, the form, the project explorer and the properties window.
Figure 1.2: VB6 Programming Environment
Form is the primary building block of a Visual Basic 6 application. A Visual Basic 6 application can actually comprises many forms; but we shall focus on developing an application with one form first. We will learn how to develop applications with multiple forms later. Before you proceed to build the application, it is a good practice to save the project first. You can save the project by selecting Save Project from the File menu, assign a name to your project and save it in a certain folder.
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