Visual Basic 6 How to Program

Preface

xxx

Computing Concepts

(24)

Introduction

(1)

What is a Computer?

(1)

Computer Organization

(1)

Evolution of Operating Systems

(1)

Personal Computing, Distributed Computing, and Client/Server Computing

(1)

Machine Languages, Assembly Languages, and High-Level Languages

(1)

History of Visual Basic

(1)

Other High-level Languages

(1)

Structured Programming

(1)

What is Visual Basic?

(1)

General Notes About Visual Basic and This Book

(1)

A Tour of the Book

(14)

Integrated Development Environment

(25)

Introduction

(1)

Integrated Development Environment Overview

(2)

Project Window

(1)

Toolbox

(2)

Form Layout Window

(1)

Properties Window

(1)

Menu Bar and Tool Bar

(1)

A Simple Program: Displaying a Line of Text

(17)

Introduction to Visual Basic Programming

(38)

Introduction

(1)

Visual Programming and Event-Driven Programming

(1)

A Simple Program: Printing a Line of Text on the Form

(8)

Another Simple Program: Adding Integers

(4)

Memory Concepts

(1)

Arithmetic

(2)

Operator Precedence

(3)

Decision Making: Comparison Operators

(19)

Control Structures: Part I

(41)

Introduction

(1)

Algorithms

(1)

Pseudocode

(1)

Introduction to Control Structures

(2)

If/Then Selection Structure

(1)

If/Then/Else Selection Structure

(4)

While Repetition Structure

(1)

Do While Repetition Structure

(1)

Do Until Repetition Structure

100

(1)

Formulating Algorithms: Case Study 1 (Counter-Controlled Repetition)

101

(2)

Formulating Algorithms with Top-down, Stepwise Refinement: Case Study 2 (Sentinel-Controlled Repetition)

103

(7)

Formulating Algorithms with Top-down, Stepwise Refinement: Case Study 3 (Nested Control Structures)

110

(19)

Control Structures: Part II

129

(48)

Introduction

130

(1)

Essentials of Counter-Controlled Repetition

130

(2)

For Repetition Structure

132

(2)

Examples Using the For/Next Repetition Structure

134

(6)

Select Case Multiple-Selection Structure

140

(7)

Do/Loop While Repetition Structure

147

(2)

Do/Loop Until Repetition Structure

149

(2)

Exit Do and Exit For Statements

151

(2)

Data Type Boolean

153

(1)

Constant Variables

154

(2)

Logical Operators

156

(3)

Structured Programming Summary

159

(5)

Visual Basic Data Types

164

(13)

Sub Procedures and Function Procedures

177

(70)

Introduction

178

(1)

Form Modules

178

(2)

Sub Procedures

180

(6)

Function Procedures

186

(4)

Call-by-Value vs. Call-by-Reference

190

(4)

Exit Sub and Exit Function

194

(3)

Storage Classes

197

(1)

Scope Rules

198

(3)

Random Number Generation

201

(7)

Example: A Game of Chance

208

(6)

Recursion and the Factorial Function

214

(3)

Another Recursion Example: The Fibonacci Series

217

(3)

Recursion vs. Iteration

220

(1)

Optional Arguments

221

(2)

Named Arguments

223

(2)

Visual Basic Math Functions

225

(1)

Code Modules

226

(21)

Arrays

247

(55)

Introduction

248

(1)

Arrays

248

(1)

Declaring Arrays

249

(2)

Examples Using Arrays

251

(7)

Passing Arrays to Procedures

258

(5)

Sorting Arrays

263

(3)

Searching Arrays: Linear Search and Binary Search

266

(5)

Multidimensional Arrays

271

(3)

Control Arrays

274

(4)

Dynamic Arrays

278

(7)

Variable Arguments: ParamArray

285

(1)

Function Array

286

(16)

Strings, Dates and Times

302

(69)

Introduction

303

(1)

Fundamentals of Characters and Strings

304

(1)

String Data Type

305

(1)

String Concatenation with & and +

305

(1)

Comparing Character Strings

306

(3)

Operator Like

309

(2)

Manipulating the Individual Characters in a String: Mid$

311

(1)

Left$, Right$, and InStr

312

(3)

Searching for Substrings in Strings using InStr and InStrRev

315

(2)

LTrim$, RTrim$ and Trim$

317

(1)

String$ and Spaces$

317

(2)

Replacing Substrings in a String with Function Replace

319

(1)

Reversing Strings with Function StrReverse

319

(1)

Converting Strings to Uppercase and Lowercase

320

(1)

Conversion Functions

321

(6)

Asc and Chr$

321

(1)

IsNumeric, Val and Str$

322

(1)

Hex$ and Oct$

323

(1)

The Type Conversion Functions

324

(3)

String Formatting

327

(13)

Function Format$ and Named Numeric Formats

327

(2)

Function Format$ and User-Defined Numeric Formats

329

(4)

Function FormatNumber

333

(2)

Function FormatCurrency

335

(3)

Function FormatPercent

338

(2)

Date and Time Processing

340

(8)

Date and Time Formatting

348

(5)

String Arrays

353

(18)

A Card Shuffling and Dealing Simulation

356

(15)

Graphics

371

(37)

Introduction

372

(1)

Coordinate Systems

372

(2)

Drawing Methods

374

(8)

Drawing Properties

382

(5)

Line Control and Shape Control

387

(3)

Colors

390

(8)

Images

398

(2)

Printer Object

400

(8)

Basic Graphical User Interface Concepts

408

(50)

Introduction

409

(1)

Controls

409

(3)

TextBox Control

412

(2)

MaskEdit Control

414

(5)

ComboBox Control

419

(4)

ListBox Control

423

(4)

Scrollbars

427

(4)

Slider Control

431

(2)

Menus

433

(4)

Pop-up Menus

437

(1)

Function MsgBox

438

(20)

Advanced Graphical User Interface Concepts

458

(50)

Introduction

459

(1)

Multiple Document Interface (MDI)

459

(10)

Multiple Forms

469

(6)

Template Forms

475

(5)

Rich TextBox Control

480

(5)

UpDown Control

485

(4)

ImageList Control

489

(3)

ImageCombo Control

492

(3)

FlatScrollBar Control (Professional and Enterprise Editions)

495

(3)

Native Code Compilation (Professional and Enterprise Editions)

498

(10)

Mouse and Keyboard

508

(29)

Introduction

509

(1)

Changing the Shape of the Mouse Pointer

509

(3)

Mouse Events

512

(3)

Mouse Buttons

515

(2)

Shift, Ctrl and Alt Keys

517

(3)

Drag-and-Drop

520

(6)

Key Events

526

(3)

KeyPreview Property

529

(8)

Error Handling and Debugging

537

(41)

Introduction

538

(1)

When Error Handling Should Be Used

539

(1)

A Simple Error-Handling Example: Divide by Zero

539

(3)

Nested on Error Statements

542

(2)

Err Object

544

(3)

Resume Statement

547

(3)

Error Handlers and the Call Stack

550

(5)

Rethrowing Errors

555

(1)

Break Mode, the Immediate Window, and the Debug Object

556

(3)

First Steps in Bug Prevention

559

(1)

Debugging Strategies

560

(2)

Debugger

562

(9)

Debug Menu and Debug Tool Bar

562

(5)

Locals Window

567

(1)

Watch Window

568

(2)

Call Stack Window

570

(1)

Debugger and Error Handlers

571

(7)

Sequential File Processing

578

(37)

Introduction

579

(1)

DirListBox, FileListBox, and DriveListBox Controls

579

(4)

Data Hierarchy

583

(1)

File System Objects

584

(15)

Creating a Sequential Access File

599

(4)

Reading Data from a Sequential Access File

603

(5)

Updating Sequential Access Files

608

(7)

Records and Random-Access Files

615

(30)

Introduction

616

(1)

Random-Access Files

616

(1)

Records as User-Defined Types

617

(2)

User-Defined Type Definitions

617

(1)

Manipulating Members of User-Defined Types

618

(1)

Creating a Random-Access File

619

(5)

Writing Data Randomly to a Random-Access File

624

(3)

Reading Data Sequentially from a Random-Access File

627

(3)

Reading Randomly from a Random-Access File

630

(3)

Example: A Transaction Processing Program

633

(12)

Object-Oriented Programming

645

(63)

Introduction

646

(2)

Data Abstraction and Information Hiding

648

(1)

Implementing a Time Abstract Data Type with a Class

649

(4)

Class Members

653

(7)

Composition: Objects as Instance Variables of Other Classes

660

(6)

Introduction to Object-Oriented Programming

666

(3)

Software Engineering with Components

669

(1)

Type Fields and Select Case Statements

669

(1)

Polymorphism

670

(1)

Visual Basic Interfaces

671

(1)

Polymorphism Examples

671

(2)

Case Study: IShape, CPoint, CCircle

673

(4)

Case Study: A Payroll System Using Polymorphism

677

(7)

Case Study: Polymorphic Processing of Shapes

684

(4)

Simulating Implementation Inheritance with Interface Inheritance and Delegation

688

(6)

Object Browser

694

(1)

Events and Classes

695

(13)

ActiveX

708

(58)

Introduction

709

(1)

Components, COM and DCOM

709

(4)

ActiveX Control Types

713

(2)

ActiveX Control Lifetime and Events

715

(1)

UserControl Object

716

(1)

Creating an ActiveX Control That Contains Constituent Controls

717

(7)

ActiveX Control Example: Clock Control

724

(7)

ActiveX Control Interface Wizard

731

(10)

Property Pages and the Property Page Wizard

741

(5)

ActiveX DLLs

746

(4)

ActiveX EXEs

750

(5)

Friend Access

755

(11)

Database Management

766

(42)

Introduction

767

(1)

Database Systems

768

(1)

Advantages of Database Systems

768

(1)

Data Independence

768

(1)

Database Languages

769

(1)

Distributed Database

769

(1)

Relational Database Model

769

(2)

Relational Database

769

(2)

Introducing the Microsoft ADO Data Control 6.0 and Microsoft DataGrid Control 6.0

771

(5)

Relational Database Overview: The Biblio.mdb Database

776

(3)

Structured Query Language

779

(5)

Basic Select Query

780

(1)

Where Clause

780

(1)

Order By Clause

781

(1)

Using Inner Join to Merge Data from Multiple Tables

782

(1)

All Titles Query from Biblio.mdb

783

(1)

Revisiting the ADO Data Control and DataGrid Control

784

(4)

Hierarchical FlexGrid Control

788

(1)

DataList and DataCombo Controls

789

(7)

Example: Using the DataCombo and DataList Controls

790

(4)

Using the BoundColumn Property

794

(2)

Using the Data Environment Designer

796

(5)

Other Programmatic Capabilities of Recordsets

801

(1)

Transaction Processing

801

(7)

Networking, the Internet and the World Wide Web

808

(52)

Introduction

809

(1)

Visual Basic Internet Controls

810

(1)

WebBrowser Control

811

(5)

Internet Transfer Control

816

(6)

Hypertext Transfer Protocol (HTTP) Connections

816

(2)

File Transfer Protocol (FTP) Connections

818

(4)

Other Properties, Methods and Events of the Internet Transfer Control

822

(1)

Winsock Control

823

(3)

Establishing a Simple Server (Using TCP Protocol)

823

(2)

Establishing a Simple Client (Using TCP Protocol)

825

(1)

Example: Client/Server Interaction with the Winsock Control

826

(8)

A Simple TCP-Based Server

826

(3)

A Simple TCP-Based Client

829

(3)

Outputs of the Client/Server Interactions

832

(2)

Winsock Control and UDP-Based Client/Server Computing

834

(5)

A Simple UDP-Based Server

834

(2)

A Simple UDP-Based Client

836

(2)

Outputs of the Client/Server Interactions

838

(1)

Other Properties, Methods and Events of the Winsock Control

839

(1)

Visual Basic Script (VBScript®): An Overview

840

(20)

Multimedia: Images, Animation, Audio

860

(36)

Introduction

861

(1)

Microsoft Agent Control

862

(8)

Multimedia MCI Control

870

(6)

A Multimedia MCI Control CD Player

872

(2)

A Multimedia MCI Control AVI File Player

874

(2)

Animation Control

876

(4)

RealAudio ActiveX Control Library

880

(2)

Marquee Control Library

882

(3)

Microsoft ActiveMovie Control

885

(11)

Data Structures, Collections and Dictionaries

896

(48)

Introduction

897

(1)

Type Variant

897

(2)

Self-Referential Classes

899

(1)

Dynamic Memory Allocation

900

(1)

Linked Lists

900

(12)

Stacks

912

(3)

Queues

915

(2)

Trees

917

(7)

Collection Object

924

(4)

Dictionary Object

928

(16)

Appendix A Operator Precedence Chart

944

(2)

Appendix B ANSI Character Set

946

(1)

Appendix C Visual Basic Internet and World Wide Web Resources

947

(6)

C.1 Visual Basic Web Resources

947

(1)

C.2 Microsoft Visual Basic Web Sites

947

(1)

C.3 Visual Basic Resources

948

(1)

C.4 FAQs

949

(1)

C.5 Tutorials for Learning VB

950

(1)

C.6 VB Newsgroups and Mailing lists

950

(1)

C.7 VB Books and Magazines

951

(1)

C.8 VB Products

952

(1)

Appendix D Number Systems

953

(14)

D.1 Introduction

954

(3)

D.2 Abbreviating Binary Numbers as Octal Numbers and Hexadecimal Numbers

957

(1)

D.3 Converting Octal Numbers and Hexadecimal Numbers to Binary Numbers

958

(1)

D.4 Converting from Binary, Octal, or Hexadecimal to Decimal

958

(1)

D.5 Converting from Decimal to Binary, Octal, or Hexadecimal

959

(2)

D.6 Negative Binary Numbers: Two's Complement Notation

961

(6)

Bibliography

967

(4)

Index

971

Welcome to Visual Basic 6 and the exciting world of Internet and World Wide Web programming! This book is by an old guy and two young guys. The old guy HMD; Massachusetts Institute of Technology (MIT) 1967 has been programming and/or teaching programming for 37 years. The two young guys PJD; MIT 1991 and TRN; MIT 1992 have each been programming for 15 years and have caught the teaching and writing "bug." The old guy programs and teaches from experience; the young guys do so from an inexhaustible reserve of energy. The old guy wants clarity; the young guys want performance. The old guy seeks elegance and beauty; the young guys want results. We got together to produce a book we hope you will find informative, interesting, challenging and entertaining. Why We Wrote Visual Basic 6 How to Program Dr. Harvey M. Deitel taught introductory programming courses in universities for 20 years with an emphasis on developing clearly written, well-structured programs. Much of what is taught in these courses is the basic principles of programming with an emphasis on the effective use of control structures, primitive data types, arrays, functions and the program development process. We present these topics in Visual Basic 6 How to Program exactly the way HMD has done in his university courses. Our experience has been that students handle the material in the early chapters on primitive data types, control structures, procedures and arrays in about the same manner as they handle introductory Pascal or C courses. There is one noticeable difference though: students are highly motivated by the fact that they are learning a leading-edge language (Visual Basic 6) and leading-edge programming paradigms (event-driven programming and object-oriented programming) that will be immediately useful to them as they leave the university environment. This increases their enthusiasm for the material. Students quickly discover that they can do great things with Visual Basic 6, so they are willing to put incredible effort into their courses. Our goal was clear: produce a Visual Basic 6 textbook for introductory university-level courses in computer programming for students with little or no programming experience, yet offer the depth and the rigorous treatment of theory and practice demanded by traditional, upper-level C and C++ courses and that satisfies professionals' needs. To meet these goals, we produced a comprehensive book because our text also patiently teaches the principles of control structures, event-driven programming, object-oriented programming and the Visual Basic 6 language. Visual Basic 6 How to Program was written fresh on the heels of C How to Program: Second Edition, C++ How to Program: Second Edition and Java How to Program: Second Edition, each of which has become the world's leading introductory textbook in its respective field. Hundreds of thousands of students and professional people worldwide have learned C, C++ and Java from these texts. Upon publication in November, 1998 Visual Basic 6 How to Program will be used in universities, professional schools and corporate training programs worldwide. We have prepared an interactive multimedia CD-ROM edition of this book - the Visual Basic 6 Multimedia Cyber Classroom. Prentice Hall offers a "value pack" edition of both Visual Basic 6 How to Program and the Visual Basic 6 Multimedia Cyber Classroom called The Complete Visual Basic 6 Training Course at a discount for people who want to use both the book and the multimedia CD. Please see the last few pages of this book for ordering instructions. The Complete Visual Basic 6 Training Course is discussed in more detail later in this Preface. We believe in Visual Basic 6. Its conceptualization by Microsoft, the creators of Visual Basic 6, is brilliant: Base a language on one of the world's most widely known languages, Basic. Endow the language with the ability to conveniently build applications