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Chapter 1. Introduction to Visual Basic .NET 2008. 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.

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Chapter 1

Chapter 1

Introduction to Visual Basic .NET 2008


Chapter objectives 1 of 2

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.


Chapter objectives 2 of 2

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 topicsin Help.


Writing windows applications with vb 1 of 2

Writing Windows Applications with VB(1 of 2)

  • Windows Graphical User (GUI) Interface

    • Defines how elements look and function

Text boxes

Check box

Radio buttons

Message box

Buttons

Picture box

Label


Writing windows applications with vb 2 of 2

Writing Windows Applications with VB(2 of 2)

Windows are called forms.

  • Elements are called controls and are added using a toolbox.


Programming languages procedural event driven and object oriented

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


  • The object model 1 of 2

    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


    Object model 2 of 2

    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.


    Object model analogy

    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


    Visual studio net

    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


  • Writing visual basic projects

    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.


  • Vb application files

    VB Application Files

    • One Solution File—think ofone solution file equals one projectHelloWorld.sln

    • Solution User Options FileHelloWorld.suo

    • Form FilesHelloForm.vb

    • Resource File for the FormHelloForm.resx

    • Form DesignerHelloForm.Designer.vb

    • Project User Options FileHelloWorld.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.


    Visual studio environment

    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

    Default Environment Settings

    Visual Studio 2008 provides a new option that allows the programmer to select the default profile for the IDE.


    The ide initial screen

    The IDE Initial Screen

    The Visual Studio IDE with the Start Page open, as it first appears in Windows XP, without an open project


    Ide main window

    IDE Main Window

    Toolbars

    Document Window

    Form Designer

    Solution Explorer WindowProperties Window

    Toolbox

    Help

    Document window

    Document window

    Solution Explorer

    Properties window


    Toolbox

    ToolBox

    • You can scroll to view more controls.

    • To sort the tools in the toolbox:

      • Right-click the toolbox and select.

      • Sort Items Alphabeticallyfrom the context menu (shortcut menu).


    Modes

    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"


    Writing your first visual basic project setting up the project

    Writing Your First Visual Basic ProjectSetting Up the Project

    Hello World Project

    1

    2

    3


    Planning the project

    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

    Setting Properties

    • Label 1

      Name messageLabel

      Textleave blank

    • Button 1

      NamepushButton

      TextPush Me

    • Button 2

      NameexitButton

      TextExit

    • Form

      NamehelloForm

      TextHello World by your name


    Setting the form properties

    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


    Writing the code

    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 eventprocedures.

    • 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.


    More on writing the code

    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


    Remark statement

    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.


    Assignment statement

    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 "


    Ending a program

    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( )


    Editor window

    Editor Window

    • Declarations Section

    • Class list

    • Method list


    Run save modify print test debug and execute

    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."


    Print the code

    Print the Code

    • File Menu, Print

    • Prints complete code listing

    • Uses arrow symbol to denote line continuation


    Finding and fixing errors

    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.


  • Naming rules and conventions

    Naming Rules and Conventions

    • Have a set of standards and always follow them.

    • No spaces, punctuation marks, or reserved words

    • Use camel casing.

      • Examples

        • messageLabel

        • exitButton

        • dataEntryForm

        • paymentAmountTextBox


    Recommended naming conventions for vb objects

    Recommended Naming Conventions for VB Objects


    Visual studio help additional info 1 of 2

    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 2008. You view the Help topics in a separate window from the VS IDE, so you can have both windows opened at the same time.


    Visual studio help additional info 2 of 2

    Visual Studio Help Additional Info (2 of 2)

    • When you choose How Do I, Search, Contents, Index, or Help Favorites from the Help menu, a new window opens on top of the IDE window. You can switch from one window to the other, or resize the windows to view both on the screen if your screen is large enough.

    Index Results window

    Main Document window


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