Visual Basic 2008 For Dummies E-Book

Bill Sempf

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch
• Veröffentlichungsjahr: 2011

Seitenzahl: 437

Beschreibung

Visual Basic is a favorite programming language, so if you're new to programming, it's a great place to start. Visual Basic 2008 For Dummies is the fun and easy way to begin creating applications right away while you get the hang of using the Visual Studio environment. Soon you'll be building all sorts of useful stuff with VB 2008! This step-by-step guide walks you through a logical series of tasks that build your skills as you get comfortable with .Net terminology, theory, tools, and design principles. You'll learn how to build an application in four different architectural styles, and you'll find out how to make your programs validate input and output, make decisions, and protect themselves from security threats. Discover how to: * Install the Visual Studio environment * Write a VB program * Use Web forms, Windows forms, and Web services * Establish good programming practices * Create class libraries * Write secure applications * Debug your applications * Work with strings and "if-then" statements * Iterate with counted and nested loops * Pass arguments and get return values * Access data with VB.NET * Work with the file system using VB You'll also find great tips for working with the VB user interface, using VB.NET in C# programming, troubleshooting your VB programs, taking your programming to the next level, and more! Once you get your hands on Visual Basic 2008 For Dummies, you'll be programming like a genius in no time!

Leseprobe

Visual Basic 2008 For Dummies

by Bill Sempf

Visual Basic® 2008 For Dummies®

Published by Wiley Publishing, Inc. 111 River Street Hoboken, NJ 07030-5774

www.wiley.com

Copyright © 2008 by Wiley Publishing, Inc., Indianapolis, Indiana

Published by Wiley Publishing, Inc., Indianapolis, Indiana

Published simultaneously in Canada

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Library of Congress Control Number: 2008923124

ISBN: 978-0-470-18238-3

Manufactured in the United States of America

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About the Author

I am Bill Sempf, and you’ll notice that I don’t write in third person. I have spent an inordinate amount of time in the last several years writing about, thinking about, and coding in VB.NET. I am a coauthor of Professional Visual Studio.NET, Effective Visual Studio.NET, Professional ASP.NET Web Services and Professional VB.NET (among others), and a frequent contributor to the Microsoft Developer Network, Builder.com, Hardcore Web Services, Inside Web Development Journal, and Intranet Journal. I have recently been an invited speaker for DevEssentials, the International XML Web Services Expo, and the Association of Information Technology Professionals. As a graduate of Ohio State University with a Bachelor of Science in Business Administration, Microsoft Certified Professional, Certified Internet Business Strategist, and Certified Internet Webmaster, I have developed over one hundred Web applications for startups and Fortune 500 companies alike.

I began my career in 1985 by helping my father (also named Bill) manage Apple IIe systems for the local library. Since then, I have built applications for the likes of Lucent Technologies, Bank One, the State of Ohio, Nationwide Insurance, and Sears, Roebuck and Co. I specialized in data-driven Web applications of all types, both public and private. Currently, I am the Senior Technology Consultant at Products of Innovative New Technology in Grove City, Ohio, a Microsoft Certified Partner, working on a Learning Management System for OmniPath, inc. (www.omnipath.com). I can be reached at [email protected].

Dedication

This edition of the book was heavily influenced by the thousands of readers all over the world who took the time to e-mail with thoughts, questions, complaints, criticism, praise and ideas. To be honest, they are why I write. The majority of my good projects have come from people who read my books and call to collaborate.

This book is dedicated to those readers. If you have taken the time to e-mail me or review the book or contact Wiley — good or bad — about this book series, thank you. Even if you are peeved because of a problem or error, you are helping make this a better product and that helps everyone.

Despite what people often think, even with the best of editing and authoring, these books aren’t perfect — they are a community effort. Without that community, the books wouldn’t be good or necessary. It’s a self-replicating cycle, and I love it.

Author’s Acknowledgments

I cannot begin to thank the amazing team at Wiley who led me ever so carefully through the process of updating this book. Katie Feltman kept on me to revise the ideas I presented, and Mark Enochs saw to it that I stuck to schedule. The entire Wiley team, in fact, is the best an author could ever hope to have. I have gotten to know them well over the last several years, and I love them all.

A project at Wendy’s International led me to ask the most detail-oriented person I have ever met — Mike Spivey — to review the technical details of this edition. Jeff Simmons reviewed the original code, and did a good job, but this book is all the better for multiple sets of eyes.

My army of peer reviewers from the original edition was fantastic: Theresa Alexander, Jim Andrews, David Deloveh, Rex Mahel, Greg McNamara, Rob Morgan, Blake Sparkes, and Gary Spencer. Here’s a special note about my father, William E. Sempf, whose education background was of inestimable help in reviewing the early concepts for the book. Then, he let me use him as a guinea pig for Part I! What a trooper!

Finally, a shout to the many Microsoft people who gave me a hand with specific questions about VB, Visual Studio, and the framework in general: Jan Shanahan and Susann Ragsdale in the Author Support Group, and Brad McCabe, Daniel Roth, Jay Roxe, and Steve Lasker, among many others, on the development teams.

Publisher’s Acknowledgments

We’re proud of this book; please send us your comments through our online registration form located at www.dummies.com/register/.

Some of the people who helped bring this book to market include the following:

Acquisitions, Editorial, and Media Development

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Technical Editor: Mike Spivey

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Publishing and Editorial for Technology Dummies

Richard Swadley, Vice President and Executive Group Publisher

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Composition Services

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Contents

Title

Introduction

About This Book

Conventions Used in This Book

What You Don’t Have to Read

Foolish Assumptions

How This Book Is Organized

Icons Used in This Book

Where to Go from Here

Part I : Getting to Know .NET Using Visual Basic

Chapter 1: Wading into Visual Basic

Visual Basic’s Role in the Framework

Saying Hello to VB 2008!

Finding More Power in Visual Studio

Chapter 2: Using Visual Studio 2008

Understanding Visual Studio Tools

Moving a Tool Window

Working with Code

Customizing with Options

Increasing Efficiency with Third-Party Tools

Chapter 3: Designing Applications in VB 2008

Making Software Simple Using the .NET Framework

Comparing Abstract Concepts with the Real World

Planning for a Project Using the Project Lifecycle

Designing the Date Calculator

Part II : Building Applications with VB 2008

Chapter 4: Building Windows Applications

A Quick Look Back at Visual Basic

Discovering Windows Controls

Making a Windows Application

Adding Functionality to a Windows Form

Adding Features to Windows Forms

Chapter 5: Building Web Applications

Seeing How ASP.NET Works with Your Web App

Discovering the Web Controls

Building Your First Web Application

Looking Below the Surface of Web Forms

Checking Out Some Cool Web Tricks

Chapter 6: Building Class Libraries

Past to Present: DLLs Defined

Designing a Library

Creating a Class Library

Delving Deeper into DLLs

Chapter 7: Building Web Services

Getting to Know XML Web Services

Designing for Web Services

Building a Web Service

Consuming a Web Service

Web Services in More Depth

Chapter 8: Debugging in VB 2008

Cool Visual Tools for Debugging

Using the Debugging Tools in the .NET Framework

Debugging the Projects

Part III : Making Your Programs Work

Chapter 9: Interpreting Strings and Things

Types of Information in Visual Basic

Making Words Work with the String Type

Finding Tools for Managing User Input

Things That Aren’t Strings — Numbers and Dates

Changing Types with Parse and TryParse

Chapter 10: Making Decisions in Code

Designing Business Logic

Depicting Logic with Flowchart Components

Implementing These Processes in Visual Basic

Chapter 11: Getting Loopy

Dealing with Zero

Writing Loops with For-Next

Using the For-Each Listing with Collections

Writing Indefinite Loops with Do-Loop

Checking at the Beginning with While

Chapter 12: Reusing Code

Reusing Code to Build Software

Avoiding the Code-Complexity Trap

Finding Other Ways to Reuse Code

Reusing Programs Outside of the Framework

Accessing DOS: But Only as a Last Resort

Chapter 13: Making Arguments, Earning Returns

Using Classes Effectively

Using Event Handlers

Making Sensible Procedures with Overloading

Flexible Objects with Generics

Controlling Objects with Threading

Part IV : Digging into the Framework

Chapter 14: Writing Secure Code

Designing Secure Software

Building Secure Windows Forms Applications

Building Secure Web Forms Applications

Using System.Security

Chapter 15: Accessing Data

Getting to Know System.Data

How the Data Classes Fit into the Framework

Getting to Your Data

Using the System.Data Namespace

Using LINQ

Chapter 16: Working with the File System

Getting to Know System.IO

Using the System.IO Namespace

Chapter 17: Accessing the Internet

Getting to Know System.Net

How the Net Classes Fit into the Framework

Using the System.Net Namespace

Chapter 18: Creating Images

Getting to Know System.Drawing

How the Drawing Classes Fit into the Framework

Using the System.Drawing Namespace

Part V : The Part of Tens

Chapter 19: Ten Tips for Using the VB User Interface

Generating Event Handlers from the Properties Window

Generating Event Handlers from the Code View

Pasting Text as HTML

Customizing Your Toolbars for Every File Type

Adding Extender Providers

Using Visual Components That Are Not So Visual

Recording Macros

Using the Task List

Inserting Snippets in Your Code

Chapter 20: Ten Ideas for Taking Your Next Programming Step

Get Visual Basic 2008 for Home Use

Update Code to Use New Tools

Join an Online Competition at TopCoder

Participate in an Open Source Project

Use Third-Party Tools in Your Projects

Integrate a Public Web Service

Try Out CodeRush and Other Code Generators

Write a Web Part

Use the DTE

Write an Article about What You Have Discovered

Chapter 21: Ten Resources on the Internet

MSDN Library

VBForDummies.net

Channel 9

ASP.NET Web

The Microsoft Public Newsgroups

.NET 247

Google CodeSearch

kbAlertz

CodePlex

<Microsoft> Google for Searching

: Further Reading

Part I

Getting to Know .NET Using Visual Basic

In this part . . .

Everyone must start somewhere, and I start at the beginning in this part. You write your first Visual Basic program, and, in doing so, you discover some of the ideas behind the .NET Framework (the backbone of this version of the language). You then get to do the only required reading in this entire book. First, you go over the use of the tool, Visual Studio. Second, you design the example application that you write in the next part.

Chapter 2

Using Visual Studio 2008

In This Chapter

Going over Visual Studio tools

Discovering how the code ties it all together

Customizing with options

Using third-party tools

Before you can effectively work with Visual Basic, you must know its tools inside and out. For the purpose of this chapter and this book, I will focus on just one — Visual Studio 2008. Visual Studio gives you access to the drag-and-drop controls that were introduced in earlier versions of Visual Basic.

Although I don’t cover the specifics of code in this chapter, I do cover all the code-generating tools that Visual Studio 2008 provides for Visual Basic. For example, I discuss the new, improved IntelliSense, which can help you remember the 288,000 methods, properties, and events in the .NET Framework, but I don’t cover the framework itself.

Understanding Visual Studio Tools

Part of the joy of programming in Visual Basic 2008 is using the tools that are provided by Visual Studio. Rapid Application Development (RAD) is a buzzword now, but when Visual Basic was first developed, it described (among other things) the ability to code faster by reusing bits of code built into the development tools.

This ability has never been more apparent than it is with Visual Basic 2008. Even though Visual Basic is a language, and it depends on Visual Studio for its environment, many tools make RAD real. In the following sections, I cover these tools. These tools are language independent, project independent, and indispensable.

Keep in mind that Visual Studio isn’t necessary to make Visual Basic programs. You can, in fact, make complete applications in the old-school style by using a command-line compiler.

Additionally, much of the documentation provided by the Microsoft Developer Network (MSDN) Library assumes an understanding of the tools. The documentation refers to the tools by name and often doesn’t clearly describe them. You must know where you are working before you can work, so the following sections take you on a tour of the Visual Studio tools.

When you installed Visual Studio, you were probably asked to install the MSDN Library. You will find it an indispensable tool (it’s what you get when you go to the Help menu, in fact). Additionally, you can find the library online at http://msdn.microsoft.com/library.

Touring the Design View

When you launch Visual Studio (usually by selecting its icon on your Start menu) and begin any visual project, you see the Design View. The Design View is where the Graphical User Interface (GUI) work takes place. Generally speaking, anytime you are working with pictures of forms, not code, you are working with the Design View. When I use the term designer window, I am referring to the actual place you do the work. The term Design View refers to the state the application is in.

In the Design View, you can accomplish the following:

Manufacture windows, Web, and smart device forms by dragging controls directly to the form in a What-You-See-Is-What-You-Get (WYSIWYG)–type environment

Work with databases and XML files visually

Create software components by visually managing the parts

In general, Design View is the core part of Visual Studio. Many of the other tools in Visual Studio depend on the Design View, in fact, and are disabled when you use another view, such as Code View, to work on your project.

Using the Design View tabs

The designer tabs have the word [Design] in the tab name, as shown in Figure 2-1, to indicate that you are using the Design View. Tabs are used in the Design and Code Views. The gray tab represents files that are open but not active. An asterisk (*) next to the filename means that you’ve made changes, but not yet saved the file.

The white tab is active and contains the editable form. When you have more than one document open, you can edit only the active form. You can drag the tabs to the left and right to change their order. Right-clicking a tab gives you a menu from which you can choose several screen management options, as shown in Figure 2-2.

Figure 2-1: A form in Design View.

Figure 2-2: Managing tab groups.

Understanding tab groups

Tab groups make it easier to copy information out of one form and into another. For example, you can have one set of pages on the top half of the screen and another on the bottom half, and copy from one and paste into the other without changing screens. You can also save and close from this menu, or get information, such as the current path or the containing folder.

Accessing controls with the Toolbox

To add form components, such as buttons and text, to the form in the Designer window, you simply drag them from the Toolbox. The Toolbox, usually seen on the left side of the Visual Studio environment and to the left of the Designer window, is where the RAD components of various project types are held for use until you need them. The Toolbox is shown in Figure 2-3.

Figure 2-3: The Toolbox.

The Toolbox is project-sensitive, meaning that controls for Web pages and smart devices don’t show up when you are writing a Windows Forms project. Because those controls can’t be used in those project types, the Toolbox doesn’t even let you see them.

You can access the controls in the following ways:

Click a control and drag it to a form, dropping it exactly where you want it.

Double-click the control, and it appears in the upper-left corner of the active form.

If you lose the Toolbox, or if it isn’t showing on your screen, you can open it by choosing View⇒Toolbox or by pressing Ctrl+Alt+X. Right-clicking the Toolbox gives you layout options, including ordering and movement. One of the options is Reset Toolbox, which puts it back the way Microsoft had it — a great feature.

The gray dividers, labeled Data or Windows Forms among other things, divide the tools in the Toolbox by category. To open a closed category, click the divider.

Visual Studio is extendable because of the Toolbox. You can use third-party components with your programs. For example, a clock control that enables the user to set the time would show up in the Toolbox. You can also use the Toolbox to store often-used pieces of text, such as comment blocks.

You can actually drag a little block of code onto the Toolbox for reuse, such as a common comment block or a sample. I use this all the time when I am presenting. I just make a new section by right-clicking the Toolbox and selecting Add Tab. Then I can just select code in the Code View (which I cover in a few pages) and drag it right under the new section header.

Changing details with the Properties window