an introduction to visual basic 2005
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An Introduction to Visual Basic 2005. 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 - PowerPoint PPT PresentationTRANSCRIPT
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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