Microsoft Visual Basic 2008: Reloaded Third Edition
Chapter OneAn Introduction to Visual Basic 2008
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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
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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
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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
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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
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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
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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
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Solutions, Projects, and Files (continued)
Figure 1-1: Illustration of a solution, project, and file
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Starting Microsoft Visual Studio 2008
Figure 1-2: How to start Microsoft Visual Studio 2008
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Figure 1-3: Visual Studio 2008 Professional Edition startup screen
Creating a Visual Basic 2008 Windows-Based Application
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Figure 1-4: How to create a Visual Basic 2008 Windows-based application
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Figure 1-5: Completed New Project dialog box
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Figure 1-6: Solution and Visual Basic Project created by Visual Studio 2008
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Managing the Windows in the IDE
Figure 1-7: How to manage the windows in the IDE
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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]
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Figure 1-8: Windows Form Designer window
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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
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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
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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
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The Properties Window (continued)
Figure 1-10: Properties window showing the properties of the Form1.vb file
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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
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Properties of a Windows Form
Figure 1-11: Windows form properties listed in the Properties window
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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
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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
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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
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The Toolbox Window (continued)
Figure 1-12: Toolbox window
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The Toolbox Window (continued)
Figure 1-13: How to add a control to a form
The Toolbox Window (continued)
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Figure 1-14: How to manipulate the controls on a form
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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
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The Label Control (continued)
Figure 1-15: Wizard application’s user interface
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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
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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
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The Code Editor Window (continued)
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Figure 1-16: How to open the Code Editor window
The Code Editor Window (continued)
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Figure 1-17: Code Editor window opened in the IDE
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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
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The Code Editor Window (continued)
• 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
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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
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The Me.Close() Instruction (continued)
Figure 1-19: Me.Close() instruction in the Click event procedure
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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
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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
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Starting and Ending an Application (continued)
Figure 1-22: Project Designer window
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Starting and Ending an Application (continued)
Figure 1-23: How to start an application
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Starting and Ending an Application (continued)
Figure 1-24: Result of starting the Wizard application
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Starting and Ending an Application (continued)
• 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
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Starting and Ending an Application (continued)
Figure 1-25: How to end an application
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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
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Using an Assignment Statement (continued)
Figure 1-26: Assignment statements entered in the Code Editor window
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Printing Your Application
Figure 1-27: How to print an application’s code and user interface
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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
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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
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Opening an Existing Solution (continued)
Figure 1-29: How to open an existing solution
Programming Tutorial
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Figure 1-46: Result of starting the Wizard application
Programming Example
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Figure 1-54: User interface
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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
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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
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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
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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
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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
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