1. CIS16 Application Development Programming with Visual Basic
Chapter One
An Introduction to Visual Basic

2. Visual Studio
Visual Basic is an object-oriented programming language (OOP)
Object: anything that can be seen, touched, or used
Class: a pattern used to create an object
Instance: an object created from a class; object is said to be instantiated
Integrated Development Environment (IDE):
Contains all the tools and features needed to create, run, and test programs
Download a free copy at

3. Visual Studio (cont'd.) Used to create software applications
Application: program or suite of programs
Windows-based application:
Has a Windows user interface
User interface: what the user sees and interacts with when using an application
Runs on a personal computer
Web-based application:
Has a Web user interface
Runs using a web server
Accessed with a computer browser

4. Creating a Visual Basic Windows Application
Windows applications consist of 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 portion of the solution
A solution may contain one or more projects

5. Visual Studio IDE

6. Setting OPTIONS

7. Create a new Visual Basic Windows Application
New Project dialog box

8. A Visual Basic Windows Application
Solution and Visual Basic Project

9. The Windows Form Designer Window
Allows you to create (design) the GUI
Graphical user interface (GUI):
What the user sees and interacts with
Windows Form object (or form):
Foundation for the user interface
Add other objects such as buttons/text boxes to form
Title bar with caption and Minimize, Maximize, and Close buttons
Tab at top of designer window has Form1.vb [Design]

10. The Solution Explorer Window
Displays a list of projects contained in this solution
Displays the items contained in each project
Solution Explorer window

11. The Solution Explorer Window – Types of project files(cont'd.)
Source file
A file containing program instructions (code)
Form file
A file containing code associated with a Windows form
Give each form file a meaningful name using the Properties window

12. The Properties Window Properties Properties window
A set of attributes that determine an object’s appearance and behavior
Properties window
Displays properties of the selected object
Default property values are assigned when an object is created 20

13. Properties of a Windows Form
Class definition
Block of code that defines the attributes and behaviors of an object
All class definitions are contained in namespaces
Namespace:
Defines a group of related classes
Dot member access operator
The period that separates words in an object’s name to indicate a hierarchy of namespaces

14. Properties of a Windows Form (cont'd.)
Name and Text Properties
Assign meaningful names to forms and use a naming convention
Pascal case
First letter of each word in the name is uppercase
First part of name is object’s purpose
Second part of name is object’s class
i.e. EmployeeDataForm
Text property
Controls the caption displayed on form’s title bar

15. The Toolbox Window Toolbox Controls
Contains objects that can be added to other objects, such as a form
Each tool has an icon and a name to identify it
Each tool represents a class from which objects, called controls, can be created
Controls
Objects displayed on a form
Represented as icons in the toolbox
Controls on a form can be selected, sized, moved, deleted, locked in place on the form and unlocked

16. The Toolbox Window (cont’d.)

17. The Toolbox Window (cont’d.)
Control names use camel case
Camel case:
Lowercase first word; uppercase first letter of each subsequent word in the name
for labels used as prompts, it is not necessary to assign meaningful names because they are never used in code
Labels used for output should have meaningful names
Label control:
Displays text that user cannot edit
Used as “prompts” to explain controls or display output
Name should end with “Label” i.e. subtotalLabel

18. The Toolbox Window (cont’d.)
Button control
Performs an immediate action when clicked
Its name should end with “Button”
Picture Box Control
Displays an image on the form

19. The Code Editor Window Events: Event procedure: Code editor window:
User actions while program is running
Examples: clicking, double-clicking, scrolling
Event procedure:
Set of instructions to be processed when an event occurs
Tells the object how to respond to an event
Code editor window:
Used to enter event procedure’s code

20. The Code Editor Window (cont'd.)

21. The Code Editor Window (cont'd.)
Class statement
Used to define a class
Class Name list box
Lists the names of objects (controls) included in the user interface
Method Name list box
Lists the events to which the selected object is capable of responding
Method: Predefined VB procedure that can be invoked (called) when needed

22. The Code Editor Window (cont'd.)
Event code template has a procedure header and a procedure footer
Begins with keywords Private Sub
Procedure name includes object name and event name
Handles clause indicates for which objects’ events this code will execute

23. The Code Editor Window (cont'd.)
Keyword
A word with special meaning in a programming language
Me keyword: refers to the current form
Me.Close() instruction
Closes the current form at run time
If the current form is the only form, the application is terminated

24. The Code Editor Window (cont'd.)
Sub procedure
Block of code that performs a task
Sequential processing
Each line is executed in sequence
Also called a sequence structure
Syntax
rules of the programming language

25. Starting and Ending an Application
When you start a VB application, the IDE creates an executable file
Executable file
Can be run outside of Visual Studio
Has a file extension of .exe
Stored in the project’s bin\Debug folder

26. Syntax Errors Syntax error
Occurs when you break one of the programming language’s rules
Most syntax errors are caused by typing errors
Rest the mouse pointer on the mistyped instruction to see details about the error

27. Syntax Errors (cont’d.)
Syntax error in the exitButton’s Click procedure
Result of placing the mouse pointer on the jagged blue line

28. Syntax Errors (cont’d.)
Syntax errors should be corrected before starting an application
If you start an application with a syntax error, a dialog box appears
Syntax error message
Result of starting an application that contains a syntax error

29. Bugs Bug Debugging An error in a program’s code
The process of locating and correcting bugs in a program

30. Closing the Current Solution
Closing a solution closes all projects and files in that solution
You are prompted to save any files that have unsaved changes

31. 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