an introduction to visual basic 2005

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An Introduction to Visual Basic 2005

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Objectives• Explain the history of programming languages• Define the terminology used in object-oriented

programming• Explain the role of the .NET Framework class library and

Common Language Runtime (CLR)• Create a Visual Basic 2005 Windows-based application• Manage the windows in the Integrated Development

Environment (IDE)• Print a project’s code• Add a control to a form• Set the properties of an object• Enter code in the Code Editor window• Save a solution

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Terms • Programs: instructions given to computers• Programmers: people who write programs• Applications programmers: write and

maintain programs to handle specific tasks• Systems programmers: write and

maintain programs that run the system, such as operating systems, device drivers, utilities

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A Brief History of Programming Languages

• Programming languages: used to communicate with the computer

• Machine language (or machine code): – Instructions are written in 0s and 1s– Only way to communicate directly with the

computer• Assembly languages: use mnemonics for

instructions• Mnemonics: alphabetic abbreviations for

instructions

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A Brief History of Programming Languages (continued)

• Assembler: program that converts assembly language instructions into machine code

• High-level languages: – Instructions resemble English language– Require an interpreter or compiler to convert

high-level language to machine code• Interpreter: translates high-level instructions line-

by-line as the program runs• Compiler: translates entire program into machine

code before running the program

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A Brief History of Programming Languages (continued)

• Procedure-oriented program: one that focuses on individual tasks and their sequence

• Object-oriented program: one that focuses on objects the program can use to accomplish its goal

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OOP Terminology

• OOP: Object-oriented programming• OOD: Object-oriented design• Object:

– Represents a real-world entity– Attributes (or properties): describe the object– Methods: behaviors or operations the object

can perform• Class: blueprint used to create an object

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OOP Terminology (continued)

• Encapsulation: the class contains all the attributes and behaviors of the object created from the class

• Instance: an object created from a class• Abstraction: the hiding of internal details of an

object• Exposed: attributes and behaviors that are not

hidden• Inheritance: ability to create one class from

another

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OOP Terminology (continued)

• Derived class: a new class created from another by inheritance

• Base class: the class used to create the new class

• Polymorphism: allows the same instructions to be carried out differently depending on the object

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Visual Studio 2005• Integrated Development Environment

(IDE):– Contains all the tools and features needed to

create, run, and test programs– Includes an editor and compiler

• Visual Studio 2005:– IDE used to create Windows or Web-based

programs– Includes Visual Basic 2005, Visual C++ 2005,

Visual C# 2005, and Visual J# 2005

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Visual Studio 2005 (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

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Visual Studio 2005 (continued)

• Web-based application: – Has a Web user interface – Runs on a server– Use a computer browser to access it

• Microsoft .NET Framework 2.0: a platform on which you create applications

• .NET languages: the programming languages included in Visual Studio

• .NET applications: applications created with Visual Studio

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Visual Studio 2005 (continued)• .NET Framework class library:

– Contains an extensive set of classes for use in .NET applications

– Reduces development time by providing reusable code

– Provides consistency among applications

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The Common Language Runtime• .NET language compilers translate program

statements into a Microsoft Intermediate Language, also called Intermediate Language (IL)

• Common Language Runtime (CLR):– Manages the execution of IL instructions

• Just-in-time (JIT) compiler: translates IL into machine code

• CLR allows compiled IL to be reused, regardless of which .NET language was used to create it

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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 part of the solution

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Starting Microsoft Visual Studio 2005

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Starting Microsoft Visual Studio 2005 (continued)

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Starting Microsoft Visual Studio 2005 (continued)

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Creating a Visual Basic 2005 Windows-Based Application

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Creating a Visual Basic 2005 Windows-Based Application

(continued)

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Creating a Visual Basic 2005 Windows-Based Application

(continued)

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Managing 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 textboxes to

create the GUI – Instance of the Windows Form class– Automatically instantiated when you create an

application

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The Windows Form Designer Window (continued)

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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

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The Solution Explorer Window (continued)

• Project Designer window:– Open by right-clicking on project folder– Allows you to set options for the project– Contains 9 tabs with groups of options

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The Solution Explorer Window (continued)

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The Solution Explorer Window (continued)

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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 object

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The Properties Window

• 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)

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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– Settings box: Right column containing the current

value of each property

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Properties of a Windows Form Object

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Properties of a Windows Form Object (continued)

• Class definition: block of code that defines the attributes and behaviors of an object

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

separates words in an object’s name• Name property: used to refer to an object in code• Hungarian notation: naming convention using a 3

or more character prefix to represent the object type• Camel casing: lowercase prefix, uppercase first

letter of each word

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Properties of a Windows Form Object (continued)

• Pascal case: – First letter and first letter of each word 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

• Splash screen: first image to appear when application starts

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Properties of a Windows Form Object (continued)

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The Toolbox Window• Toolbox:

– Contains tools used to create an application– Each tool represents a class from which to

instantiate objects• Controls:

– Objects displayed on a form– Are represented as icons in the toolbox– Can be locked in place on the form – Control names use camel casing

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The Toolbox Window (continued)

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The Toolbox Window (continued)

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The Label Tool• Label tool: represents a label control• Label control:

– Displays text that user cannot edit– Used as “prompts” to explain controls or display

output

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The Label Tool (continued)

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The Label Tool (continued)

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The Button Tool• Button tool: represents a button control• Button control:

– Performs an immediate action when clicked

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The Button Tool (continued)

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The Button Tool (continued)

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The Code Editor Window

• Events: user actions while program is running

• Event procedure: set of instructions to be executed when an event occurs

• Code editor: used to enter programming code

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The Code Editor Window (continued)

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The Code Editor Window (continued)

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The Code Editor Window (continued)

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The Code Editor Window (continued)

• Keyword: has special meaning in a programming language

• Sub procedure: block of code that performs a task

• Event’s Procedure header: – Begins with keyword Private– 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 Method

• Me.Close method: closes the current form

• Method: predefined VB procedure that can be invoked (called)

• Sequential processing: each line is executed in sequence

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The Me.Close Method (continued)

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Saving a Solution

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Starting and Ending an Application

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

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Starting and Ending an Application (continued)

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Starting and Ending an Application (continued)

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Starting and Ending an Application (continued)

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Starting and Ending an Application (continued)

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Starting and Ending an Application (continued)

• Executable file:– Can be run outside of Visual Studio 2005– Has file extension of .exe

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Starting and Ending an Application (continued)

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Using an Assignment Statement

• Assignment statement: assigns a value to a variable or property of a control

• Assignment operator: the = symbol

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Using an Assignment Statement (continued)

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Using an Assignment Statement (continued)

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Printing Your Code

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Closing the Current Solution

• Closing a solution closes all projects and files in that solution

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Closing the Current Solution (continued)

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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)

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Summary

• Program: directions given to a computer• Programming languages have progressed

from machine language to assembly language to high-level languages

• Compiler: converts high-level languages to machine instructions

• Object: can be seen, touched, or used• Objects have attributes (properties) and

behaviors (methods and events)

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Summary (continued)

• Class: a pattern from which an object can be instantiated

• Class encapsulates an object’s attributes and behaviors

• IDE: interactive development environment• Windows Form Designer window: used to

create GUI applications• Solution Explorer window: shows names of

projects and files in the solution

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Summary (continued)

• Properties window: sets an object’s property values• 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• Toolbox: contains tools for creating the GUI• Label control: contains text that a user cannot edit• Event: occurs when user interacts with GUI

elements

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Summary (continued)

• Event procedure: the code that runs when an event occurs

• Button control: performs an immediate action when clicked

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