Chapter 1

Introduction to

Visual Basic 2010

Copyright © 2011 by The McGraw-Hill Companies, Inc. All Rights Reserved. McGraw-Hill

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Chapter Objectives (1 of 2)

• Describe the process of visual program design and development.

• Explain the term object-oriented programming.

• Explain the concepts of classes, objects, properties, methods, and events.

• List and describe the three steps for writing a Visual Basic project.

• Describe the various files that make up a Visual Basic project.

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Chapter Objectives (2 of 2)

• Identify the elements in the Visual Studio environment.

• Define design time, run time, and debug time.

• Write, run, save, print, and modify your first Visual Basic project.

• Identify syntax errors, run-time errors, and logic errors.

• Use Auto Correct to correct syntax errors.

• Look up Visual Basic topics in Help.

Writing Windows Applications with VB

(1 of 2)

• Windows Graphical User (GUI) Interface

– Defines how elements look and function

Text boxes

Check box

Buttons Picture box

Radio buttons

Label

Message box

Writing Windows Applications with VB

(2 of 2)

Elements are called

controls and are added

using a toolbox.

Windows are called forms.

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Programming Languages—Procedural,

Event Driven, and Object Oriented

• Procedural—Cobol, Fortran, Basic • Program specifies exact sequence of all operations.

• Event-Driven Programming(VB 6.0 and previous) • Contain some elements of object-oriented programming, but not

all

• Object-Oriented Programming (OOP) (VB .NET) • User controls sequence

–Click event –Double Click event –Change event

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The Object Model (1 of 2)

In VB, you will work with objects that have properties, methods, and events. Each object is based on a class.

• Objects equate to Nouns. – Forms are windows.

– Controls are components contained inside a form.

• Properties equate to Adjectives. – Color or size of a Form

• Methods are like Verbs. – Typical methods include Close, Show and Clear

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Object Model (2 of 2)

• Events occur when the user takes action.

– User clicks a button, User moves a form

• Classes are templates used to create a new object.

– Classes contain the definition of all available properties,

methods, and events.

– Each new object created is based on a class.

• Creating three new buttons makes each button a

instance of the Button class.

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Object Model Analogy

• Class = automobile

• Properties of automobile class= make, model, color,

engine, year

• Object = Each individual auto is an object.

– Object is also an Instance of the automobile class.

• Methods = start, stop, speedup, slowdown

• Events of automobile class = Arrive, Crash

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Visual Studio .NET

• Included in Visual Studio .NET 2008 • Visual Basic (can also be purchased separately) • Visual C++ • C# (C sharp) • J# (J sharp) • F# (F sharp) • .NET 3.5 Framework

• Visual Studio .NET Editions • Express • Standard • Professional • Team System

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Writing Visual Basic Projects

There is a three-step process when writing a Visual Basic application—you set up

the user interface, define the properties, and then create the code.

•Planning • Design the User Interface. • Plan the Properties. • Plan the Basic Code; follow the language syntax rules; use

pseudocode (English expression or comment describing

action) then you move on to

•Programming (and use the same three-step process) • Define the User Interface. • Set the properties. • Write the Basic code.

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VB Application Files

• One Solution File—think of one solution file equals one project: HelloWorld.sln • Solution User Options File: HelloWorld.suo • Form Files: HelloForm.vb • Resource File for the Form: HelloForm.resx • Form Designer: HelloForm.Designer.vb • Project User Options File: HelloWorld.vbproj.user

Once a project is run, several more files are created by the system. The

only file that is opened directly is the solution file.

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Visual Studio Environment

The Visual Studio environment is where you create and test your

projects. In Visual Studio, it is called an

•Integrated Development Environment (IDE) consisting of various tools including:

• Form Designer

• Editor for entering and modifying code

• Compiler

• Debugger

• Object Browser

• Help Facility

Default Environment Settings

Visual Studio 2010

provides an option

that allows the

programmer to select

the default profile for

the IDE.

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The IDE Initial Screen

The Visual

Studio IDE with

the Start Page

open, as it first

appears in

Windows XP,

without an open

project

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IDE Main Window

Toolbars

Document Window

Form Designer

Solution Explorer Window

Properties Window

Toolbox

Help

Document window

Properties window

Solution Explorer

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Tool Box

You can scroll to view more

controls.

To sort the tools in the

toolbox: •Right-click the toolbox and select.

•Sort Items Alphabetically from the context menu (shortcut

menu).

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Modes

• Design Time — used when designing the user interface and writing code

• Run Time — used when testing and running a project

• Break Time — if/when receiving a run-time error or pause error

"Look at the Title Bar"

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Writing Your First Visual Basic Project Setting Up the Project

1

2

3

Hello World Project

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Planning the Project

• Design the user interface. • Set up the form.

–Resize the form. –Place a label and a

button control on the

form using the

toolbox.

–Lock the Controls in place.

• After the user interface is designed, the next step is to set

the properties.

Setting Properties

• Label 1 Name MessageLabel Text leave blank

• Button 1

Name PushButton Text Push Me

• Button 2

Name ExitButton Text Exit

• Form

Name HelloForm Text Hello World by

your name

Setting the Form Properties

• The default startup object is Form1

• The name of the form should always be

changed to adhere to

naming rules

• The properties window shows

the files properties

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Writing the Code

• While the project is running, the user can perform actions. • Each action by the user causes an event to occur. • Write code for the events you care about; the events you

want to respond to with code.

• Code is written as event procedures. • VB will ignore events for which you do not write code. • VB will automatically name event procedures as the object

name, an underscore(_) and the name of the event.

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More on Writing the Code

• When writing the code for your first project, you will use the following:

• Remark Statement • Assignment Statement • Ending a Program • Editor Window

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Remark Statement

• Also known as Comment, used for documentation; every procedure should begin with a remark statement providing

explanation.

• Non-executable • Automatically colored Green in Editor • Begins with an apostrophe ( ' )

• On a separate line from executable code • At the right end of a line of executable code

'Display the Hello World message.

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Assignment Statement

• Assigns a value to a property or variable • Operates from right to left — the value appearing on the right

side of the equal sign is assigned to the property named on the

left of the equal sign.

• Enclose text strings in quotation marks (" ")

MessageLabel.Text=" Hello World "

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Ending a Program

• Methods always have parentheses. (This will help you distinguish them from Properties which never have parentheses.)

• To execute a method of an object you write:

Object.Method()

• Current Form may be referenced as Me

Me.Close( )

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Editor Window

• Declarations Section • Class list • Method list

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Run, Save, Modify, Print, Test, Debug,

and Execute

• Run Project • Open Debug Menu, Start Debugging. • Start Debugging button on the toolbar. • Press F5, the Start Debugging command.

• Save Project — File Menu, Save All. • Modify Project if needed. • Print the Code. • Correct any Errors and Rerun. • When you start executing your program, the first step is called

compiling, which means that the VB statements are converted to Microsoft Intermediate Language (MSIL). Your goal is to have no errors during the compile process: a clean compile.

"Help is always available from the

Help Menu or by pressing F1."

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Print the Code

• File Menu, Print • Prints complete code listing • Uses arrow symbol to denote line continuation

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Finding and Fixing Errors

• Syntax Errors • Breaks VB’s rules for punctuation, format, or spelling • Smart editor finds most syntax errors, compiler finds the rest. • The editor identifies a syntax error with a squiggly blue line

and you can point to an error to pop up the error message.

• You can display the Error List window and line numbers in the source code to help locate the error lines.

• Run-Time Errors • Statements that fail to execute, such as impossible arithmetic

operations

• Logic Errors • Project runs, but produces incorrect results.

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Naming Rules and Conventions

• Have a set of standards and always follow them. • No spaces, punctuation marks, or reserved words • Use Pascal casing.

•Examples –MessageLabel –ExitButton –DataEntryForm –PaymentAmountTextBox

Recommended Naming Conventions

for VB Objects Object Class Example

Form DataEntryForm

Button ExitButton

Label TotalLabel

TextBox PaymentAmountTextbox

Radio button BoldRadiobutton

CheckBox PrintSummaryCheckBox

Horizontal Scroll Bar RateHorizontalScrollBar

Vertical Scroll Bar TemperatureVerticalScrollBar

PictureBox LandscapePictureBox

ComboBox BookListComboBox

ListBox IngredientsListBox

SoundPlayer IntroPageSoundPlayer

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Visual Studio Help Additional Info (1 of 2)

• Visual Studio has an extensive Help facility. • Filter MSDN help to display VB topics only. • Run MSDN from hard drive, CD, or Web. • You can access MSDN on the Web at

http://msdn.microsoft.com

• The Help system display is greatly changed and improved in Visual Studio 2010. You view the Help topics in a separate window web browser from the VS IDE, so you can have both windows opened at the same time.

http://msdn.microsoft.com/

Visual Studio Help Additional Info (2 of 2)

• The opening Help page allows you to search for a topic, or to choose from a list of topic areas such as: Welcome to Visual Studio 2010, Documentation, What’s New, Walkthroughs, etc.