Book Image

Visual Basic Quickstart Guide

By : Aspen Olmsted
Book Image

Visual Basic Quickstart Guide

By: Aspen Olmsted

Overview of this book

Whether you’re an absolute beginner or an experienced developer looking to learn the Visual Basic language, this book takes a hands-on approach to guide you through the process. From the very first chapters, you'll delve into writing programs, exploring core concepts such as data types, decision branching, and iteration. Additionally, you’ll get to grips with working with data structures, file I/O, and essential object-oriented principles like inheritance and polymorphism. This book goes beyond the basics to equip you with the skills to read and write code across the entire VB family, spanning VB Script, VBA, VB Classic, and VB.NET, enabling you to handle legacy code maintenance with ease. With clear explanations, practical examples, and hands-on exercises, this book empowers you to tackle real-world software development tasks, whether you're enhancing existing projects or embarking on new ones. It addresses common challenges like distinguishing between the variations of the VB programming language to help you choose the right one for your projects. Don't let VB's extensive legacy daunt you; embrace it with this comprehensive guide that equips you with practical, up-to-date coding skills to overcome the challenges presented by Visual Basic's rich history of over two decades.
Table of Contents (27 chapters)
Free Chapter
1
Part 1:Visual Basic Programming and Scripting
9
Part 2:Visual Basic Files and Data Structures
14
Part 3:Object-Oriented Visual Basic
20
Part 4:Server-Side Development

Exception handling

In VB, exception handling is primarily accomplished using structured error-handling constructs, such as Try...Catch...Finally blocks, rather than inheritance. However, it’s worth noting that exception handling in VB does involve classes and inheritance but in a different manner.

VB uses the Exception class, which is a base class for all exceptions in the .NET Framework, to handle errors and exceptions. The Exception class has several derived classes representing specific types of exceptions, such as SystemException and ApplicationException. When an exception occurs, VB throws an object of one of these derived exception classes, which you can then catch and handle using Try...Catch...Finally blocks.

Here’s an example demonstrating exception handling in VB using Try...Catch...Finally:

Sub Main()
    Try
        Dim n1 As Integer = 20
        Dim...