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prepared by James T. Perry University of San Diego. Ch. 1: Introduction to VB. Writing windows applications with VB Prog. languages: procedural, object oriented, & event driven Writing VB projects The VB environment Writing your first VB project Finding & fixing errors Visual Basic help.

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prepared by

James T. Perry

University of San Diego


Ch. 1: Introduction to VB

  • Writing windows applications with VB

  • Prog. languages: procedural, object oriented, & event driven

  • Writing VB projects

  • The VB environment

  • Writing your first VB project

  • Finding & fixing errors

  • Visual Basic help


Labels

Text boxes

Frame

Check boxes

Option buttons

Command buttons

Image

Picture box

Writing Windows Apps. with VB

  • The Windows GUI


Graphic User Interface

  • Graphic User Interface (GUI) comprises

    • Forms

    • Controls

    • Event-driven programming


Prog. Languages: procedural, object oriented, & event driven

  • The Object Model

    • Objects (nouns)controls

    • Properties (adjectives)form1.Caption

    • Methods (verbs)debug.print

  • Versions of Visual Basic

    • Working Model

    • Learning Edition

    • Professional Edition

    • Enterprise Edition


Planning Visual Basic Projects

  • The three-step process for planning projects

    • Design the user interface

      Sketch the screens with forms and controls needed

    • Establish the objects' properties

      Write down the properties for each object

    • Plan the Basic code

      Write out pseudocode for actions your program will perform


Writing Visual Basic Projects

  • The three-step process for writing projects

    • Design the user interface

      Create the forms and controls you previously sketched

    • Set the objects' properties

      Give each object a name and set their properties

    • Write the Basic code

      Write out Visual Basic code to carry out your application's actions


Visual Basic Projects

  • Visual Basic projects create several files

    • Project file: .VBP

      Holds the names of other files in the project

    • Form files: .FRM

      Each form is saved as a separate file

      Form file contains a description of a form's objects and the Basic code attached to a form

    • Standard code module: .BAS (optional)

    • Custom controls: .OCX (optional)

    • Form information: .VBW


The Visual Basic Environment

  • Form, Project Explorer, Properties, and Form Layout Windows

  • Toolbox

  • Main Visual Basic window

  • Toolbar, Form location & size information

  • Help

  • Design- , Run- , and Break Time


The Toolbox

  • Tool box contents vary based on which version of Visual Basic you are running.

  • Toolbox contains a common set of tools across all VB versions


The Visual Basic Toolbar

  • The buttons on the toolbar are shortcuts

  • Toolbar buttons are a quick way to activate frequently used commands

  • Each button stands for a command that you can also select a the Visual Basic menu


Writing Your First VB Project

  • Set up your Visual Basic workspace

  • Define user interface

  • Set properties

  • Write code

  • Visual Basic code statements

  • Run, save, open, modify, & print the Hello World project

  • Documentation


Set Up Your VB Workspace

  • Set up Options to reflect these settings:


Define the User Interface

  • Resize the form

    • Drag the lower-right handle to enlarge the form

    • Drag any handle in the middle of a side to enlarge the form in that direction only

  • Place controls on the form

    • Click the label tool

    • Click and drag the mouse (a crosshair) to place the control on the form


Set Properties

  • Set the Name and Caption properties

    • Always set the Name property before writing code

    • Next, set the Caption property

  • The Name property identifies the object internally--so you can refer to it in code

  • The Caption property externally idenfities an object


Write Code

  • You write code enclosed in event procedures, which respond to typical VB events.

    Private Sub cmdPush_Click()

    . . . (your code goes here)

    End Sub

  • VB automatically supplies the event procedure Sub/End Sub statements


Visual Basic Code Statements

  • Remark statement is any code line beginning with an apostrophe

  • Assignment statement

  • End statement


Code the Event Procedures for Hello World

  • Write the Push event code for the Push Me button (cmdPush)

  • Write the Push event code for the Exit button (cmdExit)


Run/Save/Open/Modify the Project

  • Test the project:

    • Click Run, Start

      (or click the Start button on the toolbar)

    • Click the Push Me button

    • Click the Exit button

  • Save the project and the form

  • Make modifications to the form

  • Print the project documentation:

    • Form Image, Code, and Form as Text


Finding & fixing errors

  • Compile (syntax) errors

  • Run-Time (semantic) errors

  • Logic errors

  • Project Debugging


Naming Conventions

  • Objects have special prefixes that help identify the object's general type

  • Programmers follow the conventions because it simplifies coding and debugging

  • Never use default names for objects


Visual Basic Help

  • Help includes all of the Microsoft Developer Network (MSDN) library.

  • The Working Model does not contain the extensive MSDN facilities

  • Access MSDN online at

    http://msdn.Microsoft.com


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