Programming
Cha pt e r 1:
The Vi sua l Ba si c Envi r onm e nt
Programming Languages
▹ E.g. C++. BASIC, COBOL, Pascal,
Java, C#, Visual Basic
▹ Visual Studio containsObject
Oriented Programming Languages
▹ Create programs where user can
press keys, buttons that access
different functions
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Objects, Properties and
Me t hods
OBJECTS
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Properties
Methods
CLASS
▹ Blueprint used to create object
▹ Object becomes a class and class
contains/encapsulates attributes
and behaviours
▹ Instance of a class–create an
object from a class
￭ Ferrari Enzo, Ferrari F40 are
instances (examples) of the
Ferrari class
￭ Casio Telememo 30, Seiko
Kinetic, FitBit Watch are
instances of a watch class
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▹ Application: program
or suite of programs
▹ Windows-based
application:
￭ Has a Windows user
interface
￭ Runs on a personal
computer
▹ User interface: what the
user sees and interacts
with when using an
application
▹ Web-based application:
￭ Has a Web user interface
￭ Runs on a server
￭ Accessed with a
computer browser
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MS Visual Studio 2015
▹ IDE–Integrated Development
environment
Contains all tools needed to easily
create applications
▹ You create the user interface
￭ How the user sees the
￭
system
How the user uses the
system
▹ Remember as developers you
are creating applications that
other people will use
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The Graphical User Interface
(GUI )
Labels
Text Boxes
Radio
Buttons
Picture Box
CheckBox
Buttons
Drop Down
Box
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Starting and Configuring
Vi sua l St udi o
8
Starting and Configuring
Vi sua l St udi o
(cont ’d.)
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Starting and Configuring
Vi sua l St udi o
(cont ’d.)
1
0
Figure 1-3: Options dialog box
Starting and Configuring
Vi sua l St udi o
(cont ’d.)
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Figure 1-4: Microsoft Visual Studio Community 2015 startup
screen
Creating a VB Windows Form 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
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MS Visual Basic 2015
▹ Starting MS Visual
Studio
▹ Chooseyour
environment
▹ Start a project
New Project dialog box
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MS Visual Basic 2015 Interface
Files of
solution
Form
ToolBox
Properties
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Name of file
Title Bar can be changed using
form properties
Windows Form Object
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▹ All objects placed on form
▹ GUI–Graphical User Interface
▹ Forms have various properties
that could be changed–Project
Designer Window
Creating a VB Windows Form Application
▹ Source file
￭ A file containing program instructions
▹ Code
￭ Program instructions
▹ Form file
￭ A file containing code associated with a
￭
Windows form
Give each form file a meaningful name using
the Properties window
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VB Views
▹ WindowsForm 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]
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Properties Window
Various Properties for
each object
▹ Text, Name, Font,
Size, StartPosition
etc.
▹ Description at the
bottom of the
window
Each Property affects
the functioning and
appearance of the
object
▹ For example, the
Text property of the
form displayes the
title of the form
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Creating a VB Windows Form Application
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Accessing the Project Properties
Double Click to
access
Various options
could change
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Properties of a Windows
For m
(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
▹ Text property
￭ Controls the caption displayed on form’s
title bar
2
1
Properties of a Windows
For m
(cont 'd.)
▹ StartPosition property
￭ Determines the form’s position on the
screen when application starts
▹ Font Property
￭ General shape of characters in text
￭ Recommended font is Seqoe UI font
▹ Size Property
￭ Two numbers separated by a comma and
￭
a space
The first number represents the object’s
width, and the second number
represents its height
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2
The Toolbox Window
▹ Toolbox
￭ 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
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3
The Toolbox Wi ndow
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Using the Format Menu
▹ Format menu:
￭ provides options for manipulating
￭
controls on the form
First control selected is the reference
control
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The Code Editor Window
▹ Events:
￭ 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
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The Code Editor Wi ndow
▹ Class statement
￭ Used to define a class
▹ Syntax
￭ Rules of the language
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The first program
Write a program that says Hello
when a button is clicked.
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Writing VB Programs
▹
1.
2.
3.
3 Step process
Design the user interface
Plan the properties
Plan the basic code
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The Interface
Text property for
form
Message displayed in
a textbox
Place your screenshot here
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Buttons to display
message in chosen
language
The code
Each button needs to
be programmed.
When clicked:
▹ The label on the
form changes
using the =
▹ The text within the
textbox changes to
the language using
the =
▹ Remarks in green
start with ‘
Place your screenshot here
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Some initial coding
st a t e m e nt s
Assignment
▹ Represented using =
Using methods of an
object
▹ Allocates a value to an
object/variable/
control/property
▹ Command the object
to do something
▹ Object.property = value
▹ TextBox1.Hide()
▹ Textbox1.Text =
“Hello”
▹ Me.BackColor =
Color.Red
▹ Object.Method
▹ Me.Close()
Remarks
▹ Comments made by
the programmer in
the code
▹ Shown in green
▹ Tells someone what
the code is going to
do
▹ Compiler of VB
ignores these
statements
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Finding and Fixing Errors
▹ 3 types –Syntax, Runtime and
Logic
Debugging–Finding and fixing errors
▹ Syntax
￭ Breaking VB’s rules
￭ VB generally underlines these
errors for you
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Checking your errors
▹ Run Time
￭ Error occurs during execution -
Statements that fail to execute, such
as impossible arithmetic operations
▹ Logical error
￭ Program runs properly from start to
￭
finish
The answer is wrong/unexpected
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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"