COVER PAGE

ii Practical Approach to Programming in Visual Basic

First Published 2010

Published in Nigeria by:

STEMIC PUBLICATIONS

P. O. Box 10612,

Benin City,

Nigeria.

E-mail: st_mico@yahoo.com

Copyright © O. Omorogiuwa and M. S. Okundamiya

All Right Reserved

No part of this publication may be reproduced, stored in any retrievable

system, or transmitted in any form or by any means: electronic, mechanical,

photographic (photocopying), recording or otherwise without the prior

written permission of the publisher.

ISBN: 978-978-907-303-0

Printed by:

Eguavoen Printers

53 Wire Road, Opp Emotan College Gate,

Benin City.

Tel: +23480358112619

iiiM. S. Okundamiya

PREFACE

Practical Approach to Programming in Visual Basic is intended to be of use

to both novices seeking to learn Visual Basic, and to those proficient in other

languages that plan to cross-train from other programming languages. Visual

Basic language provides a uniquely powerful, yet easy to learn programming

environment allowing even the absolute beginner to rapidly create and

deploy Windows applications.

Practical Approach to Programming in Visual Basic is divided into seven

chapters. It begins with the essential concepts of computer programming

aimed at equipping the reader with the required knowledge and techniques

for effective and practical computer programming without necessarily having

a pre-knowledge on computer programming. Chapter two introduces the

basic concepts of VB 6.0: with practical steps on how a beginner can create

his (or her) first VB application, modify and add control properties, and how

such applications can be improved. Chapter three through six detailed on

Visual Basic language covering topics such as Visual Basic data and variable

types: single and multi-dimensional arrays, along with their declaration

statement; control properties: string handling, file I/O, date and time

manipulation; operators and flow control, and functions. Finally it ends with

data storage, database creation and access using customized VB programs.

The CD gives the exact demonstration of the VB designs taught in the

textbook and more. Throughout this book, liberal use is made of code

excerpts providing practical examples of theory in action, which practically

guides both seasoned and inexperienced programmers. It is intended that

iv Practical Approach to Programming in Visual Basic

having read this book, the programmer will confidently be able to developing

Windows applications using Visual Basic.

We sincerely appreciate God Almighty for His infinite mercy, wisdom, love

and protection over our families. Thanks to our dearly beloved brethren,

Franklin Ibegbulem and Hillaree John, for painstakingly going through this

work despite their tight schedule.

O. Omorogiuwa

M. S. OkundamiyaApril, 2010.

vM. S. Okundamiya

CONTENTS

Preface iii

Contents v

Chapter One: Concept of Computer Programming.

1.1 Introduction 1

1.2 Program Developmental Cycle 1

1.2.1 Analyzing the Program 2

1.2.2 Developing a Solution 2

1.2.3 Coding the Solution 4

1.2.4 Testing and Debugging the Program 5

1.3 Qualities of a Good Program 5

1.4 Classification of Programming Languages 6

1.4.1 Low Level Language (LLL) 6

1.4.2 High Level Language (HLL) 7

1.4.3 Very High Level Language (VHLL) 7

1.4.4 Procedural Languages 7

1.4.5 Non - Procedural Languages 8

1.5 Translators 8

1.5.1 Assembler 8

vi Practical Approach to Programming in Visual Basic

1.5.2 Interpreter 8

1.5.3 Compiler 8

1.6 Elements of a Programming Language 9

1.6.1 Data and Variables 9

1.6.2 Statements and Operators 11

1.6.3 Program Flow Control 13

1.6.4 Array 18

1.6.5 Functions 18

1.6.6 Structures 18

Chapter Two: Overview of Visual Basic 6.0 Programming Language.

2.1 Introduction 19

2.2 Defining Basic Terms 21

2.2.1 Object 21

2.2.2 Form 21

2.2.3 Screen 21

2.2.4 Clipboard 22

2.2.5 Application 22

2.2.6 Object-Oriented Programming

22

2.2.7 Event-Driven Programming 22

2.2.8 Procedure-Oriented Programming 23

viiM. S. Okundamiya

2.3 Creating the Graphical User Interface (GUI) 23

2.3.1 Guiding Principles 24

2.3.2 Interface Style 25

2.4 Writing the Code 26

2.5 Creating Your First Application 28

2.5.1 Starting Visual Basic 6.0 29

2.5.2 Adding Controls to the Form 32

2.5.3 Improving Your Application 43

Chapter Three: Data, Variables and Constants in Visual Basic.

3.1 Introduction 45

3.2 Visual Basic Data Types 45

3.2.1 Numeric Data Types 45

3.2.2 Non-Numeric Data Types 46

3.2.3 Suffixes for Literals 47

3.3 Variables 48

3.3.1 Naming Conventions 49

3.3.2 Declaring Variables 49

3.3.3 Scope of Variables 51

3.3.4 Assigning Values to Variables 57

3.4 Constants 57

3.5 Arrays in VB 58

3.5.1 Dimension of an Array 58

3.5.2 Declaring Arrays 59

3.5.3 Working with Arrays 60

Chapter Four: Control Properties in Visual Basic.

4.1 Introduction 65

viii Practical Approach to Programming in Visual Basic

4.2 Handling of Common Controls 66

4.2.1 Label 66

4.2.2 Text Box 68

4.2.3 Command Button 68

4.2.4 Picture Box 73

4.2.5 Frame 73

4.2.6 Image Box 74

4.2.7 List Box 74

4.2.8 Combo Box 75

4.2.9 Check Box 78

4.2.10 Option Button 78

4.2.11 Drive List Box 79

4.2.12 Directory List Box 80

4.2.13 File List Box 80

4.3 Graphics 81

4.3.1 Adding or Removing Pictures 82

4.3.2 Drawing Controls 83

4.4 Multimedia 83

Chapter Five: Operators and Flow Control in Visual Basic.

5.1 Arithmetic Operators 85

5.2 Conditional (Relational) Operators 88

5.3 Logical Operators 88

5.4 Using the If . . . Then . . . Else Statement with Operators 89

ixM. S. Okundamiya

5.5 Using Select Case…End Select Control

Structure with Operators 95

5.6 Looping 100

5.6.1 Do Loop 101

5.6.2 For . . . Next Loop 104

Chapter Six: Functions in Visual Basic.

6.1 Introduction 107

6.2 VB Built-In Functions 107

6.2.1 Message Box ( ) Function 107

6.2.2 The Input Box ( ) Function 113

6.3 Mathematical Functions 115

6.4 Formatting Functions 119

6.4.1 Tab Function 119

6.4.2 Space Function 120

6.4.3 Format Function 121

6.5 String Manipulation Functions 123

6.6 Dates and Times 127

Chapter Seven: Data Storage in Visual Basic.

7.1 Introduction 130

7.2 Data Files 130

7.2.1 Types of Files 131

7.2.2 Opening and Closing Files 132

7.3 Working with a Sequential File 139

7.4 Working with a Random File 151

References 157

x Practical Approach to Programming in Visual Basic

Index 158