microsoft visual basic 2008: reloaded third edition chapter one an introduction to visual basic 2008

Microsoft Visual Basic 2008: Reloaded Third Edition

Chapter OneAn Introduction to Visual Basic 2008

Microsoft Visual Basic 2008: Reloaded, Third Edition 2

ObjectivesAfter studying this chapter, you should be able to:• Define the terminology used in programming• Create a Visual Basic 2008 Windows-based

application• Manage the windows in the Integrated Development

Environment (IDE)• Set the properties of an object• Add a control to a form• Use the Label, Button, and PictureBox tools


Objectives (continued)

• Enter code in the Code Editor window• Save a solution• Start and end an application• Print an application’s code and interface• Write an assignment statement • Close and open an existing solution• Find and correct a syntax error


Programmers

• Programs: directions given to computers• Programmers: people who write programs• Typical tasks performed by a programmer include:

– Analyze a problem statement or project specification– Plan an appropriate solution and convert the solution

to instructions that the computer can follow• Programmers should be able to:

– Think logically and pay attention to detail– Be patient and persistent, and able to work under

pressure– Be creative in designing solutions and testing them


Programming Languages

• Programming languages: used to communicate with the computer

• Object-oriented programming language: a language that allows the programmer to use objects to accomplish a program’s goal

• Object: anything that can be seen, touched, or used– Every object is created from a class

• Class: a pattern or blueprint used to create an object

• Visual Basic is available as a stand-alone product (Express Edition) or as part of Visual Studio 2008

Visual Studio 2008

• Integrated Development Environment (IDE):– Contains all the tools and features needed to create,

run, and test programs– Includes an editor and compiler

• Visual Studio 2008:– IDE used to create Windows- or Web-based

programs– Includes Visual Basic 2008, Visual C++ 2008, and

Visual C# 2008



Visual Studio 2008 (continued)

• Application: program or suite of programs• Windows-based application:

– Has a Windows user interface – Runs on a desktop computer

• User interface: what the user sees and interacts with when using an application

• Web-based application: – Has a Web user interface – Runs on a server– Accessed with a computer browser


Solutions, Projects, and Files

• Solution: a container that stores projects and files for an entire application

• Project: a container that stores files associated with a specific piece of the solution

• A solution may contain one or more projects


Solutions, Projects, and Files (continued)

Figure 1-1: Illustration of a solution, project, and file


Starting Microsoft Visual Studio 2008

Figure 1-2: How to start Microsoft Visual Studio 2008


Figure 1-3: Visual Studio 2008 Professional Edition startup screen

Creating a Visual Basic 2008 Windows-Based Application


Figure 1-4: How to create a Visual Basic 2008 Windows-based application


Figure 1-5: Completed New Project dialog box


Figure 1-6: Solution and Visual Basic Project created by Visual Studio 2008


Managing the Windows in the IDE

Figure 1-7: How to manage the windows in the IDE


The Windows Form Designer Window

• Windows Form Designer window:– Allows you to create (design) the GUI

• Graphical user interface (GUI): – What the user sees and interacts with when using the

application• Windows Form object (or form):

– Adds other objects such as buttons and text boxes to the form to create the GUI

– Has a title bar with caption and Minimize, Maximize, and Close buttons

– Tab at top of designer windows has [Designer]


Figure 1-8: Windows Form Designer window


The Solution Explorer Window

• Solution Explorer window:– Displays a list of projects contained in this solution– Displays the items contained in each project

Figure 1-9: Solution Explorer window


The Solution Explorer Window (continued)

• Source file: a file containing program instructions• Code: program instructions• Form file: a file containing code associated with a

Windows form• Give each form file a meaningful name using the

Properties window


The Properties Window

• Properties: a set of attributes that determine an object’s appearance and behavior

• Properties window: displays properties of selected object

• Default property values are assigned when an object is created


The Properties Window (continued)

Figure 1-10: Properties window showing the properties of the Form1.vb file


The Properties Window (continued)

• Properties window includes an Object box and a Properties list

• Object box:– Located immediately below Properties window title bar– Contains the name of the selected object

• Properties list:– Left column displays names of properties

• Use the Alphabetical or Categorized buttons to sort the display of properties

– Settings box: Right column containing the current value of each property


Properties of a Windows Form

Figure 1-11: Windows form properties listed in the Properties window


Properties of a Windows Form (continued)

• Class definition: block of code that defines the attributes and behaviors of an object– All class definitions are contained in namespaces

• Namespace: defines a group of related classes• Dot member access operator: the period that

separates words in an object’s name to indicate a hierarchy of namespaces

• Name property: used to refer to an object in code– Give each object a meaningful name

• Hungarian notation: naming convention using three or more character prefix to represent the object type


Properties of a Windows Form (continued)

• Pascal case: – First letter of each word in the name is uppercase– First part of name is object’s purpose– Second part of name is object’s class

• Text property: controls the caption displayed on form’s title bar

• StartPosition property: determines the form’s position on the screen when application starts

• Font: general shape of characters in text– Recommended font is Seqoe UI font

• Point: a measure of font sizes; one point = 1/72 inch


The Toolbox Window

• Toolbox: – Contains objects that can be added to other objects,

such as a form– Each tool has an icon and a name to identify it– Each tool represents an object, called a control

• Controls: – Objects displayed on a form– Represented as icons in the toolbox– Can be locked in place on the form


The Toolbox Window (continued)

Figure 1-12: Toolbox window



Figure 1-13: How to add a control to a form



Figure 1-14: How to manipulate the controls on a form


The Label Control

• Label control:– Displays text that user cannot edit– Used as “prompts” to explain controls or display output– Name should end with “Label”

• Control names use camel case• Camel casing: lowercase first word; uppercase first

letter of each subsequent word in the name• Not necessary to assign meaningful names for labels

used as prompts because they are never used in code

• Labels used for output should have meaningful names


The Label Control (continued)

Figure 1-15: Wizard application’s user interface


The Button Control

• Button control:– Performs an immediate action when clicked– Its name should end with “Button”

• Text property: specifies the text that appears on the button’s face

The Picture Box Control

• Picture box control: used to display an image on a form

• Image property: specifies the image to display• SizeMode property: handles how the image will be

displayed– Settings: Normal, StretchImage, AutoSize,

CenterImage, or Zoom


The Code Editor Window

• Events: user actions while program is running– Examples: clicking, double-clicking, scrolling

• Event procedure: set of instructions to be executed when an event occurs– Tells the object how to respond to an event

• Code editor: used to enter programming code


The Code Editor Window (continued)


Figure 1-16: How to open the Code Editor window



Figure 1-17: Code Editor window opened in the IDE


The Code Editor Window (continued)• Class statement: used to define a class

– Begins with Public Class <class name>– Ends with End Class

• Class Name list box: lists the names of objects (controls) included in the user interface

• Method Name list box: lists the events to which the selected object is capable of responding

• When you select a control from the Class Name list box and a method name, a code template for the event appears in the Code Editor window

• Syntax: rules of the language



• Keyword: a word with special meaning in a programming language

• Event code template has a procedure header and procedure footer

• Sub procedure: block of code that performs a task• Event’s procedure header:

– Begins with keywords Private Sub– Procedure name includes object name and event

name– Handles clause indicates for which objects’ events

this code will execute


The Me.Close() Instruction

• Me.Close() instruction: closes the current form at run time– If the current form is the main form, the application is

terminated• Me keyword: refers to the current form• Method: predefined VB procedure that can be

invoked (called) when needed• Sequential processing: each line is executed in

sequence– Also called a sequence structure


The Me.Close() Instruction (continued)

Figure 1-19: Me.Close() instruction in the Click event procedure


Saving a Solution

• An asterisk appears on the designer and Code Editor tabs if a change was made since the last time the solution was saved

Figure 1-20: How to save a solution


Starting and Ending an Application

• Startup form: the form to be displayed when the application starts

Figure 1-21: How to specify the startup form


Starting and Ending an Application (continued)

Figure 1-22: Project Designer window



Figure 1-23: How to start an application



Figure 1-24: Result of starting the Wizard application



• When you start a VB application, the IDE creates an executable file

• Executable file:– Can be run outside of Visual Studio 2008– Has a file extension of .exe– Stored in the project’s bin\Debug folder



Figure 1-25: How to end an application


Using an Assignment Statement

• Properties window is used to set property values at design time

• Assignment statement: assigns a value to a variable or property of a control– Used to set property values at run time

• String: zero or more characters enclosed in quotation marks

• Assignment operator: the = symbol


Using an Assignment Statement (continued)

Figure 1-26: Assignment statements entered in the Code Editor window


Printing Your Application

Figure 1-27: How to print an application’s code and user interface


Closing the Current Solution

• Closing a solution closes all projects and files in that solution– You are prompted to save any files that have

unsaved changes

Figure 1-28: How to close a solution


Opening an Existing Solution

• Only one solution can be open at any one time• If a solution is already open, opening a different

one will close the currently open solution


Opening an Existing Solution (continued)

Figure 1-29: How to open an existing solution

Programming Tutorial


Figure 1-46: Result of starting the Wizard application

Programming Example


Figure 1-54: User interface


Summary

• Program: directions given to a computer• Object-oriented programs focus on objects to

accomplish a task• Object: can be seen, touched, or used, and has

attributes that control its appearance and behavior• Class: a pattern from which an object can be

created• Applications created in Visual Studio 2008 are

composed of solutions, projects, and files


Summary (continued)

• Windows Form Designer window: used to create GUI applications

• Windows Form object is created from the Windows Form class

• Solution Explorer window: shows names of projects and files in the solution

• Properties window: lists an object’s properties and their values

• All class definitions are contained in namespaces


Summary (continued)• System.Windows.Forms namespace contains

definition of the Windows Form class and class definitions for objects added to a form

• Dot member access operator indicates a hierarchy of namespaces

• Name property: used to refer to an object in code• Text property of a form: specifies the text to be

displayed in the title bar of the form and in the taskbar when running

• Form’s StartPosition property sets the position of the form when it first appears at run time


Summary (continued)

• Recommended font is Segoe UI in 9-point size• Toolbox: contains tools for creating the GUI• A control’s Text property value is displayed inside

the control• Controls on a form can be selected, sized, moved,

deleted, or locked at design time• Label control: contains text that a user cannot edit• Button control: performs an immediate action when

clicked• Picture box control: displays an image on a form

Summary (continued)

• Event procedure: the code that tells an object how to respond to an event

• Use the Class Name and Method Name list boxes to select an object and event to code

• Code Editor: provides code templates for each object’s event procedures

• Can display line numbers in the Code Editor window

• Me.Close() instruction: can terminate an application


Summary (continued)

• You should save your solution every 10-15 minutes• When an application is started in the IDE, the

computer creates an executable file• Use an assignment statement to set a property

value at run time• Can print your application’s code, with or without

line numbers• Closing a solution closes all projects and files in it• Only one solution can be open in the IDE at any

timeMicrosoft Visual Basic 2008: Reloaded, Third Edition 61

microsoft visual basic 2008: reloaded third edition chapter one an introduction to visual basic 2008

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