Introduction to Visual Basic

1
Chapter 1

• Introduction to Visual Basic

2
Introduction to Visual Basic

• Objective Writing windows applications with
  Visual Basic
• Programming languages Language for communicating
  with a computer
• Machine Code (Machine Language)
• Assembly Language
• High Level Language
• The VB environment
• Writing your first VB project
• Finding fixing errors

3
Definitions and Terms

• Program/Programmer
• User
• Algorithm
• See p. 12-13
• Disk File Folder Filename Path
• Directory Subfolder Root Folder
• Graphical User Interface (GUI)
• Point, Click, Double-Click, Hover

4
Graphical User Interface

• Visual Basic allows you to create GUIs
• Graphic User Interface (GUI) comprises
• Forms
• Controls
• Event-driven programming
• Revolutionized the Computer Industry
• Allows input forms or boxesmuch friendlier
  interface

5
Writing Windows Applications with Visual Basic

• The Windows GUI

6
Graphic User Interface

• Controls The responsive objects a programmer
  places on a window
• These objects recognize user actions such as
  mouse movements and button clicks
• A good analogy For Example
• Objects (nouns) Option button
• Properties (adjectives) What it looks like
• Methods (verbs) What it does

7
Planning Visual Basic Projects

• The three-step process for planning projects
• (p. 21)
• 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

8
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

9
When the Program is Running

• Visual Basic monitors the controls in the window
  to detect any event (click, for example)
• When events detected, examine program to see if
  theres a procedure associated with it
• If there is a procedure, execute it
• If there is no procedure, wait for the next event

10
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-

11
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
• 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

12
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

13
Set Up Your VB Workspace

• Set up Options to reflect these settings

14
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

15
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

16
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

17
Visual Basic Code Statements

• Remark statement is any code line beginning with
  an apostrophe
• Assignment statement
• End statement

18
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

19
Finding fixing errors

• Compile (syntax) errors
• Run-Time (semantic) errors
• Logic errors
• Project Debugging

20
Homework

• Text Box Walkthrough p. 43
• Command Button Walkthrough p. 49
• Label Walkthrough p. 50
• Picture Box Walkthrough p. 51