1. Required Books
An Introduction to Programming Using Visual Basic 2010, (w/VS2010 DVD), 8/E, D.I. Schneider , Prentice-Hall, 2010
Text comes with DVD to install VB at home

2. Academic Honesty Statement
Academic honesty plays a key role in our efforts to maintain a high standard of academic excellence and integrity. Students are advised that ALL acts of intellectual dishonesty will be handled in accordance with the SFU Academic Honesty and Student Conduct Policies ( Students are also encouraged to read the School's policy information page (
Cheaters will be caught  0.

3. Syllabus

4. Syllabus

5. Your background? Any programming? “Expert” at Windows?
Excel formulas (if, lookup, …)?
Installing programs?

6. Chapter 1 - Intro
Chapter 1

7. Chapter 1 - An Introduction to Computers and Problem Solving
1.2 Windows, Folders, and Files
1.3 Program Development Cycle
1.4 Programming Tools

8. Communicating with the Computer
Machine language
low level, hard for humans to understand
Visual Basic
high level, understood by humans, consists of instructions such as Click, If, Do
Usable in other applications (Word, Excel…)

9. Computers and Complicated Tasks
Tasks are broken down into instructions that can be expressed by a computer language
A program is a sequence of instructions
Programs can be only a few instructions or millions of lines of instructions
Examples?
In real life?
In computers?

10. All Programs Have in Common
Take data and manipulate it to produce a result
Input – Process – Output
Input
Output

11. Hardware and Software Hardware Software
The physical components of a computer
Keyboard
Disk drive
Monitor
Software
The instructions that tell the computer what to do

12. Programmer and User
Programmer – the person who solves the problem and writes the instructions for the computer
User – any person who uses the program written by the programmer

13. Problem Solving Developing the solution to a problem
Algorithm – a step by step series of instructions to solve a problem

14. Problem Solving
Problems are solved by carefully reading them to determine what data are given and what outputs are requested
Then a step-by-step procedure is devised to process the given data and produce the requested output
This procedure is called an algorithm
Finally, a computer program is written to carry out the algorithm
Problems are solved by carefully reading them to determine what data are
given and what outputs are requested. Then a step-by-step procedure is devised to
process the given data and produce the requested output. This procedure is called an
algorithm. Finally, a computer program is written to carry out the algorithm.
Algorithms are discussed in Section 2.2.

15. Visual Basic 2010
BASIC originally developed at Dartmouth in the early 1960s
Visual Basic created by Microsoft in 1991
Visual Basic 2010 is similar to original Visual Basic, but more powerful

16. XP versus Vista
Windows XP Windows Vista

17. 1.2 Windows, Folders, and Files
Windows and Its Little Windows
Mouse Actions
Files and Folders

18. Windows and Its Little Windows
Difference between Windows and windows.
Title bar indicates if window is active.

19. Mouse Actions
Clicking (single-clicking) means pressing and releasing the left mouse button once.
Double-clicking means clicking the left mouse button twice in quick succession
Note: An important Windows convention is that clicking selects an object so you can give Windows or the document further directions about it, but double-clicking tells Windows to perform a default operation.
Pointing means moving your mouse across your desk until the mouse pointer is over
the desired object on the screen.
Hovering means to linger the mouse at a particular place and wait for a message or
menu to appear.
Clicking (sometimes people say single-clicking) means pressing and releasing the
left mouse button once. Whenever a sentence begins “Click on ,” you need to
1. move the mouse pointer until it is at the object you are supposed to click on and
2. press and release the left mouse button.
An example of a sentence using this jargon might be “Click on the button marked Yes.”
You also will see sentences that begin “Click inside the ” This means to move the
mouse pointer until it is inside the boundaries of the object, and then click.
Double-clicking means clicking the left mouse button twice in quick succession
(that is, pressing it, releasing it, pressing it, and releasing it again quickly so that
Windows doesn’t think you single-clicked twice). Whenever a sentence begins
“Double-click on ”, you need to
1. move the mouse pointer until it is at the object you are supposed to double-click
on and
2. press and release the left mouse button twice in quick succession.
For example, you might be instructed to “Double-click on the little box at the far left
side of your screen.”
Note: An important Windows convention is that clicking selects an object so you
can give Windows or the document further directions about it, but double-clicking tells
Windows to perform a default operation. For example, double-clicking on a folder will
open that folder.
Dragging usually moves a Windows object. If you see a sentence that begins “Drag
the ”, you need to

20. Mouse Actions
Pointing means moving your mouse across your desk until the mouse pointer is over the desired object on the screen
Hovering means to linger the mouse at a particular place and wait for a message or menu to appear
Dragging usually moves a Windows object. If you see a sentence that begins “Drag the ”, you need to click on the object and hold
Pointing means moving your mouse across your desk until the mouse pointer is over
the desired object on the screen.
Hovering means to linger the mouse at a particular place and wait for a message or
menu to appear.
Clicking (sometimes people say single-clicking) means pressing and releasing the
left mouse button once. Whenever a sentence begins “Click on ,” you need to
1. move the mouse pointer until it is at the object you are supposed to click on and
2. press and release the left mouse button.
An example of a sentence using this jargon might be “Click on the button marked Yes.”
You also will see sentences that begin “Click inside the ” This means to move the
mouse pointer until it is inside the boundaries of the object, and then click.
Double-clicking means clicking the left mouse button twice in quick succession
(that is, pressing it, releasing it, pressing it, and releasing it again quickly so that
Windows doesn’t think you single-clicked twice). Whenever a sentence begins
“Double-click on ”, you need to
1. move the mouse pointer until it is at the object you are supposed to double-click
on and
2. press and release the left mouse button twice in quick succession.
For example, you might be instructed to “Double-click on the little box at the far left
side of your screen.”
Note: An important Windows convention is that clicking selects an object so you
can give Windows or the document further directions about it, but double-clicking tells
Windows to perform a default operation. For example, double-clicking on a folder will
open that folder.
Dragging usually moves a Windows object. If you see a sentence that begins “Drag
the ”, you need to

21. Files and Folders
File: holds programs or data. Its name usually consists of letters, digits, and spaces.
Folder: contains files and other folders (called subfolders).
Think of a disk as a large folder that contains several smaller folders each with its own name.
The naming of folders follow th same rule as naming files
Each folder is identified by listing its name preceded by a backslash
A filespec typically includes the drive, path and the filename.
File is identified by a small
directory or folder is identified by a folder icon
executable file: is identified by a rectangle with a thin bar across top
Go over: How to create a folder
to rename a folder
to delete a folder or file
to Copy a folder or file
To move a folder or file

22. Key Terms in using Folders and Files
Example
Disk
Hard disk, CD
File name
PAYROLL
Extension
.TXT
Filename
PAYROLL.TXT
Path
TextFiles\PAYROLL.TXT
Filespec
C:\TextFiles\PAYROLL.TXT
Think of a disk as a large folder that contains several smaller folders each with its own name.
The naming of folders follow th same rule as naming files
Each folder is identified by listing its name preceded by a backslash
A filespec typically includes the drive, path and the filename.
File is identified by a small
directory or folder is identified by a folder icon
executable file: is identified by a rectangle with a thin bar across top
Go over: How to create a folder
to rename a folder
to delete a folder or file
to Copy a folder or file
To move a folder or file

23. Windows Explorer Used to view, organize and manage folders and files.
Manage: copy, move, delete

24. Biographical History of Computing
Chapter 1

25. 1800s George Boole – devised Boolean algebra
Charles Babbage – created "analytical engine“
Augusta Ada Byron – first computer programmer
Herman Hollerith – founder of company that would become IBM

26. 1930s
Alan Turing – deciphered German code in WWII; father of artificial intelligence
John V. Atanasoff – inventor of first electronic digital special purpose computer

27. 1940s Howard Aiken – built large scale digital computer, Mark I
Grace M. Hopper – originated term "debugging"; pioneered development and use of COBOL
John Mauchley and J. Presper Eckert – built first large scale general purpose computer, ENIAC

28. 1940s continued John von Neumann – developed stored program concept
Maurice V. Wilkes – built EDSAC, first computer to use stored program concept
John Bardeen, Walter Brattain, and William Shockley – developed transistor that replaced vacuum tubes

29. 1950s
John Backus – created Fortran; early user of interpreters and compilers
Reynold B. Johnson – invented the disk drive
Donald L. Shell – developed efficient sorting algorithm

30. 1960s John G. Kemeny and Thomas E. Kurtz – invented BASIC
Corrado Bohm and Guiseppe Jacopini – proved that any program can be written with only 3 structures: sequence, decision, and loops
Edsger W. Dijkstra – stimulated move to structured programming by declaring "GOTO" harmful

31. 1960s continued
Harlan B. Mills – advocated use of structured programming
Donald E. Knuth – wrote definitive work on algorithms.
Ted Hoff, Stan Mazer, Robert Noyce, and Frederico Faggin – developed first microprocessor

32. 1960s continued
Douglas Engelbart – invented computer mouse

33. 1970s
Ted Codd - software architect; laid the groundwork for relational databases
Paul Allen and Bill Gates - cofounders of Microsoft Corporation
Stephen Wozniak and Stephen Jobs - cofounders of Apple Computer Inc.
Dan Bricklin and Dan Fylstra - wrote VisiCalc, the first electronic spreadsheet program

34. 1970s continued
Dennis Ritchie - creator of the C programming language.
Ken Thompson - created the Unix operating system
Alan Kay – developer of Smalltalk, a pure object- oriented language
Don Chamberlain - created a database programming language, later known as SQL,

35. 1980s
Phillip “Don” Estridge - at IBM directly responsible for the success of the personal computer.
Mitchell D. Kapor - cofounder of Lotus Corporation
Tom Button - group product manager for applications programmability at Microsoft;
headed the team that developed QuickBasic, QBasic, and Visual Basic.

36. 1980s continued Alan Cooper - considered the father of Visual Basic.
Tim Berners–Lee - father of the World Wide Web.
Charles Simonyi - father of Word.
Bjarne Stroustrup - creator of the C++ programming language.
Richard M. Stallman - founded Free Software Foundation

37. 1990s Marc Andreessen - inventor of the Web browser.
James Gosling – creator of Java.
Linus Torvalds - developed the popular Linux operating system.

38. 2000s Sergey M. Brin and Lawrence E. Page – founders of Google
Mark Zuckerberg – founder of Facebook.
Steve Chen, Chad Hurley, and Jawed Karim – founders of YouTube.

39. 1.3 Program Development Cycle
Performing a Task on the Computer
Program Planning

40. Terminology tip A computer program may also be called: Project
Application
Solution

41. Program Development Cycle
Software refers to a collection of instructions for the computer
The computer only knows how to do what the programmer tells it to do
Therefore, the programmer has to know how to solve problems
Take big problem, break it down
Break it down further
Repeat until you get to very fundamental steps

42. Performing a Task on the Computer
Determine Output
Identify Input
Determine process necessary to turn given Input into desired Output

43. Pictorial representation of the problem solving process

44. Problem-solving: approach like algebra class
How fast is a car traveling if it goes 50 miles in 2 hours?
Output:
Input:
Process:

45. Program Planning A recipe is a good example of a plan
Ingredients and amounts are determined by what you want to bake
Ingredients are input
The way you combine them is the processing
What is baked is the output

46. Program Planning Tips
Always have a plan before trying to write a program
The more complicated the problem, the more complex the plan must be
Planning and testing before coding saves time coding

47. Program development cycle
1. Analyze: Define the problem. 2. Design: Plan the solution to the problem. 3. Choose the interface: Select the objects (text boxes, buttons, etc.). 4. Code: Translate the algorithm into a programming language. 5. Test and debug: Locate and remove any errors in the program. 6. Complete the documentation: Organize all the materials that describe the program.

48. Documentation
Why is documentation important? 48

49. 1.4 Programming Tools Flowcharts Pseudocode Hierarchy Chart
Direction of Numbered NYC Streets Algorithm
Class Average Algorithm

50. Programming Tools
Three tools are used to convert algorithms into computer programs:
Flowchart - Graphically depicts the logical steps to carry out a task and shows how the steps relate to each other.
Pseudocode - Uses English-like phrases with some Visual Basic terms to outline the program.
Hierarchy chart - Shows how the different parts of a program relate to each other.

51. Problem solving example
How many stamps do you use when mailing a letter?
One rule of thumb is to use one stamp for every five sheets of paper or fraction thereof.

52. Algorithm
INPUT:
2. PROCESSING:
3. PROCESSING:
4. OUTPUT:

53. Flowcharts
Graphically depict the logical steps to carry out a task and show how the steps relate to each other.

54. Flowchart symbols

55. Flowchart symbols continued

56. Flowchart example

57. Pseudocode
Uses English-like phrases with some Visual Basic terms to outline the task.

58. Pseudocode example Determine the proper number of stamps for a letter
Read Sheets (input)
Set the number of stamps to Sheets / 5 (processing)
Round the number of stamps up to the next whole number (processing)
Display the number of stamps (output)

59. Hierarchy charts
Show how the different parts of a program relate to each other
Hierarchy charts may also be called
structure charts
HIPO (Hierarchy plus Input-Process-Output) charts
top-down charts
VTOC (Visual Table of Contents) charts
All are similar to a company’s organization chart.

60. Hierarchy charts example

61. Divide-and-conquer method
Used in problem solving – take a large problem and break it into smaller problems solving the small ones first
Breaks a problem down into modules

62. Statement structures
Sequence – follow instructions from one line to the next without skipping over any lines
Decision - if the answer to a question is “Yes” then one group of instructions is executed. If the answer is “No,” then another is executed
Looping – a series of instructions are executed over and over

63. Sequence flow chart

64. Decision flow chart

65. Looping flow chart

66. Direction of Numbered NYC Streets Algorithm
Problem: Given a street number of a one-way street in New York City, decide the direction of the street, either eastbound or westbound
Discussion: in New York City even numbered streets are Eastbound, odd numbered streets are Westbound

67. Flowchart

68. Pseudocode
Determine the direction of a numbered NYC street Get street If street is even Then Display Eastbound Else Display Westbound End If

69. Hierarchy Chart

70. Movie Rating Example Kids want to watch the movie, “Avatar”.
Decide whether he or she can watch the movie based on his or her age.
Solution?

71. Class Average Algorithm
Problem: Calculate and report the grade- point average for a class
Discussion: The average grade equals the sum of all grades divided by the number of students
Output:
Input:
Processing:

72. Flowchart
We need a loop to read and then add the grades for each student in the class
Inside the loop, we also need to count the number of students in the class
grade = sum of grades / number of students

73. Pseudocode
Program: Determine the average grade of a class Initialize Counter and Sum to 0 Do While there are more data Get the next Grade Add the Grade to the Sum Increment the Counter Loop Compute Average = Sum / Counter Display Average

74. Hierarchy Chart

75. Comments
When tracing a flowchart, start at the start symbol and follow the flow lines to the end symbol
Testing an algorithm at the flowchart stage is known as desk checking
Flowcharts, pseudocode, and hierarchy charts are program planning tools that are not dependent on the programming language being used

76. Comments continued
There are four primary logical programming constructs
sequence
decision
loop
unconditional branch
Appear in some languages as GOTO statements
Involves jumping from one place in a program to another
Structured programming uses the sequence, decision, and loop constructs but forbids the unconditional branch
There are four primary logical programming constructs: sequence, decision, loop,
and unconditional branch. Unconditional branch, which appears in some lan-guages
as Goto statements, involves jumping from one place in a program to anoth-er.
Structured programming uses the first three constructs but forbids the fourth.

77. Tips and tricks of flowcharts
Flowcharts are time-consuming to write and difficult to update
For this reason, professional programmers are more likely to favor pseudocode and hierarchy charts
Because flowcharts so clearly illustrate the logical flow of programming techniques, they are a valuable tool in the education of programmers

78. Tips and tricks of pseudocode
There are many styles of pseudocode
Some programmers use an outline form
Some use a form that looks almost like a programming language
The pseudocode in the case studies of this text focus on the primary tasks to be performed by the program and leaves many of the routine details to be completed during the coding process

79. Tips and tricks of hierarchy charts
Many people draw rectangles around each item in a hierarchy chart
In the text, rectangles are omitted to encourage the use of hierarchy charts by making them easier to draw

80. For next week
Read Chapter 2 & Appendix D
Install Visual Studio 2010

81. Programming is useful!

82. Review of Chapter 1

83. Trouble installing/accessing Visual Studio?

84. Review Computer Computer programs
a device that can perform calculations and make logical decisions much faster than humans can
Computer programs
a sequence of instructions
Input—Process—Output (data—manipulate—results)
Hardware: physical components (keyboard, screen, mouse, hard drive, memory, DVDs, CPU—Central Processing Unit)
Software: programs that run on a computer

85. Review Programmers vs. Users Computer languages:
Machine language: computers understand.
High-level language: resembles everyday English. Compilers convert it into machine language. (Visual Basic, C, C++, Java, C#, Fortran, COBOL, …)

86. Review
Algorithm: a step by step series of instructions to solve a problem
Visual Basic.NET is:
Event-driven
Object-oriented
User-friendly (GUI-based)

87. Visual Basic, Controls, and Events
Chapter 2
Visual Basic, Controls, and Events

88. Visual Basic, Controls, and Events
2.1 An Introduction to Visual Basic
2.2 Visual Basic Controls
2.3 Visual Basic Events

89. Visual Basic 2010
Before VB, a window required hundreds of lines of code
Now
Fewer instructions
Consistent
Less time
User-friendly

90. Visual Basic 2010 Language used to create Windows applications.
Provides a Graphical User Interface or GUI.
The sequence of instructions executed in the program is controlled by events.

91. Before VB

92. Before VB Program complicated, unfriendly Required parameters
Once input was entered, hard to go back

93. How to Develop a VB Application
Design the Interface for the user
Literally draw the GUI
Drag buttons/text boxes/etc onto form
Determine which events the controls on the window should recognize
Write the code for those events.
Test

94. What happens when program is running
VB monitors the controls for events
If event occurs, it runs procedures assigned to that event
If no event exists, it goes back to #1

95. Different Versions of Visual Basic
Version 1.0 – Version 2.0 – 1992
Version 3.0 – Version 4.0 – 1995
Version 5.0 – Version 6.0 – 1998
Visual Basic.NET – (NOT BACKWARD COMPATIBLE WITH EARLIER VERSIONS)
Visual Basic 2005 – November 2005
Visual Basic 2008 – November 2007
Visual Basic 2010 – April 2010
Visual Basic 2012 – Sept 2012

96. 2.2 Visual Basic Controls Invoking Visual Basic Text Box Control
Button Control
Label Control
List Box Control
Name Property
Help / Fonts / Auto Hide
Positioning and Aligning Controls

97. Visual Basic Start Page
Point out menu bar; especially file item.

98. Start a New Project

99. New Project Dialog Box

100. Initial Visual Basic Screen

101. Toolbox

102. Toolbox Initiates an Action
Get information (input) Display information (output)
Shows what type of information is displayed in the textbox.
Displays output/make selections

103. Placing Control Forms
3 Ways to Place a Control from the Toolbox onto the Form Window
Double-click
Drag and Drop
Click, Point, and Drag

104. Text Box Control Used for input and output
When used for output, ReadOnly property is set to True
Tasks button
Sizing handles

105. Properties Window
Press F4 to display the Properties window for the selected control.
105
Categorized view Alphabetical view

106. Properties Window
Selected control
Properties
Settings

107. Some Often Used Properties
Text
Autosize
Font.Name
Font.Size
ForeColor
BackColor
ReadOnly

108. Setting Properties Click on property name in left column.
Enter its setting into right column by typing or selecting from options displayed via a button or ellipses.

109. ForeColor Property Click on ForeColor.
Click on button at right of settings box.
Click on Custom tab to obtain display shown.
Click on a color.
The 16 white boxes at the bottom of the grid are used to create custom colors. (Explained in Appendix B.)

110. Font Property Click on Font in left column.
Click on ellipsis at right of settings box to obtain display shown,
Make selections.

111. Button Control
The caption on the button should indicate the effect of clicking on the button.
Text property determines caption.
To add the button, double-click on the button icon in the ToolBox, or single click and click and drag

112. Add an "access key"

113. Label Control Used to identify the contents of a text box/button/etc
Text property specifies caption
By default, label automatically resizes to accommodate caption on one line
When the AutoSize property is set to False, label can be resized manually. Used primarily to obtain a multi- rowed label

114. List Box Control Initially used to display several pieces of output.
In Chapter 9 used to select from a list.

115. The Name Property Used by the programmer to refer to a control in code
Setting for Name property near top of Properties window.
Name must begin with a letter, be less than 215 characters long, and may include numbers and letters.
Use appropriate 3- or 4- character naming prefix

116. Control Name Prefixes Control Prefix Example button btn btnCompute
label
lbl
lblAddress
text box
txt
txtAddress
list box
lst
lstOutput

117. Renaming the Form Initial name is Form1
The Solution Explorer window lists a file named Form1.vb
To rename the form, change the name of this file to newName.vb
newName should begin with prefix frm

118. Fonts
Proportional width fonts take up less space for "I" than for "W" – like Microsoft Sans Serif
Fixed-width fonts take up the same amount of space for each character – like Courier New
Fixed-width fonts are used for tables

119. Excellent walkthroughs in book
Demo the previous
Label
Button
Colours
Font
Renaming
Excellent walkthroughs in book

120. Auto Hide Hides Toolbox when not in use
Vertical push pin icon indicates auto hide is disabled.
Click the push pin to make it horizontal and enable auto hide.
Push pin

121. Positioning Controls
Proximity line

122. Aligning Controls
Snap line

123. Aligning Controls
Snap line

124. Tab Order
Tab index
Tab index determines the order in which the control receives the focus while tabbing.
Setting of tab order invoked from Edit window.
The tab indices determine the order in which controls receive the focus during tabbing.

125. 2.3 Visual Basic Events An Event Procedure Walkthrough
Properties and Event Procedures of the Form
The Header of an Event Procedure

126. Event An event is an action, such as the user clicking on a button
Usually, nothing happens in a Visual Basic program until the user does something and generates an event
What happens is determined by statements

127. controlName.property = setting
Sample Statements
General Form:
controlName.property = setting
txtBox.ForeColor = Color.Red
txtBox.Visible = True
txtBox.Text = "Hello World"
What do the above mean?

128. What events could there be?
Sample Form
txtFirst
txtSecond
btnRed
What events could there be?

129. Focus
When you click on a text box, a cursor appears in the text box, and you can type into the text box
Such a text box is said to have the focus
If you click on another text box, the first text box loses the focus and the second text box receives the focus

130. Examples of Events General Form: controlName.event btnShow.Click
txtBox.TextChanged
txtBox.Leave

131. Events
Take form, double click on textbox

132. Events
Enter area to write code for control

133. Examples of Events
Select Event

134. 3 steps in creating a VB program
Create the interface; that is, generate, position, and size the objects
Set properties; that is, configure the appearance of the objects
Write the code that executes when events occur

135. Code Editor Code Editor tab Form Designer tab Class Name box
Method Name box

136. Structure of an Event Procedure
Private Sub objectName_event(...) Handles objectName.event statements End Sub (...) is filled automatically with (ByVal sender As System.Object, ByVal e As System.EventArgs)
Header

137. Create an Outline for an Event Procedure; i.e. header and End Sub
Double-click on a control or
Use the Class Name and Method
Name boxes.
(We nearly always use the first
method.)

138. Double Click on txtFirst
Sample Form
txtFirst
txtSecond
btnRed
Double Click on txtFirst

139. Code for Walkthrough
Public Class frmDemo Private Sub txtFirst_TextChanged(...) Handles txtFirst.TextChanged End Sub End Class

140. Code for Walkthrough
Public Class frmDemo Private Sub txtFirst_TextChanged(...) Handles txtFirst.TextChanged txtFirst.ForeColor = Color.Blue End Sub End Class

141. Automatically pops up to give the programmer help.
IntelliSense
Automatically pops up to give the programmer help.
txtFirst.

142. Click tab to return to Form Designer
Code Editor
Click tab to return to Form Designer

143. Double-click on btnRed
Sample Form
txtFirst
txtSecond
btnRed
Double-click on btnRed

144. Code for Walkthrough
Public Class frmDemo Private Sub txtFirst_TextChanged(...) Handles txtFirst.TextChanged txtFirst.ForeColor = Color.Blue End Sub Private Sub btnRed_Click(...) Handles btnRed.Click End Class

145. Code for Walkthrough
Public Class frmDemo Private Sub txtFirst_TextChanged(...) Handles txtFirst.TextChanged txtFirst.ForeColor = Color.Blue End Sub Private Sub btnRed_Click(...) Handles btnRed.Click txtFirst.ForeColor = Color.Red End Class

147. Event Procedure Select txtFirst from Class Name box drop-down list
Select Leave from Method Name box drop-down list

148. Code for Walkthrough
Private Sub txtFirst_Leave(...) Handles txtFirst.Leave End Sub

149. Code for Walkthrough
Private Sub txtFirst_Leave(...) Handles txtFirst.Leave txtFirst.ForeColor = Color.Black End Sub

150. Header of Event Procedure
Private Sub btnRed_Click(…) Handles btnRed.Click
Identifies event
Name, can be changed.
Private Sub Button_Press(…) Handles btnRed.Click

151. Handling Multiple Events
Event procedure can be invoked by two events.
Private Sub Happening(...)
Handles btnRed.Click,txtSecond.Leave
txtFirst.ForeColor = Color.Red
End Sub

152. Altering Properties
The following won't work: frmDemo.Text = "Demonstration"
The form is referred to by the keyword Me.
Me.Text = "Demonstration"

153. Text File Holds data to be processed by programs
Can be created, viewed, and managed by the Visual Basic IDE
Create: Use “Add New Item” input dialog box
View: Click on filename in Solution Explorer
Manage: Use Solution Explorer like Windows Explorer

154. Sample Text File
Mike Jones John Smith
PAYROLL.TXT

155. Sample Text File Mike Jones 9.35 35 John Smith 10.75 33 name
hourly wage
hours worked
PAYROLL.TXT

156. Our Text File Convention
PAYROLL.TXT uses one item of data per line. That will be our convention in this book.

157. Use Property Window to View all Possible Events for a Control
button

158. Run an Existing Program
Click on Open Project in the File menu
Navigate to the program’s folder
Click on the program’s folder
Double-click on the file with extension .sln
In the Solution Explorer double-click on the file with extension .vb. (The Form Designer will appear.)
Press F5 to run the program

159. Run Program

161. Review of Chapter 2

162. How to Develop a VB Application
Design the Interface for the user
Literally draw the GUI
Drag buttons/text boxes/etc onto form
Determine which events the controls on the window should recognize
Write the code for those events

163. What happens when program is running
VB monitors the controls for events
If event occurs, it runs procedures assigned to that event
If no event exists, it goes back to #1.

164. Initial Visual Basic Screen

165. Properties Window
Selected control
Properties
Settings

166. Control Name Prefixes Control Prefix Example button btn btnCompute
label
lbl
lblAddress
text box
txt
txtAddress
list box
lst
lstOutput

167. Positioning Controls
Proximity line

168. Aligning Controls
Snap line

169. Code Editor Code Editor tab Form Designer tab Class Name box
Method Name box

170. Sample Code
Public Class frmDemo Private Sub txtFirst_TextChanged(...) Handles txtFirst.TextChanged txtFirst.ForeColor = Color.Blue End Sub End Class

171. Chapter 3

172. Variables, Input, and Output
3.1 Numbers
3.2 Strings
3.3 Input and Output

173. Arithmetic Operations
Numbers are called numeric literals
Five arithmetic operations in Visual Basic
+ addition
- subtraction
* multiplication
/ division
^ exponentiation

174. Numeric Expressions
2 + 3
3 * (4 + 5)
2 ^ 3

175. Displaying Numbers Let n be a number or a numeric expression.
What does the statement
lstBox.Items.Add(n)
do?

176. Example 1: Form

177. Example 1: Code and Output
Private Sub btnCompute_Click (...) Handles btnCompute.Click lstResults.Items.Add(5) lstResults.Items.Add(2 * 3) lstResults.Items.Add((2 ^ 3) – 1) End Sub What is the result?

178. A numeric variable is a name to which a number can be assigned.
Examples:
speed
distance
interestRate
balance

179. Variables Assignment: speed = 50 Declaration: Dim speed As Double
Data type
Variable name
Assignment:
speed = 50

180. Variables Visual Basic type structure Storage size Value range Boolean
4 bytes
True or False
Byte
1 byte
0 to 255 (unsigned)
Char
2 bytes
0 to (unsigned)
Date
8 bytes
January 1, 1 CE to December 31, 9999
Decimal
12 bytes
+/-79,228,162,514,264,337,593,543,950,335
with no decimal point;
Double
E308 to E-324 for negative values; E-324 to E308 for positive values

181. Variables Visual Basic type structure Storage size Value range Integer
4 bytes
-2,147,483,648 to 2,147,483,647
Long
8 bytes
-9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
Object
Any type can be stored in a variable of type Object
Short
2 bytes
-32,768 to 32,767
Single
E38 to E-45 for negative values; E-45 to E38 for positive values
String
10 bytes + (2 * string length)
0 to approximately two billion Unicode characters

182. Initialization Dim varName As Double Dim varName As Double = 50
Numeric variables are automatically initialized to 0:
Dim varName As Double
To specify a nonzero initial value
Dim varName As Double = 50

183. Numeric Expressions
Numeric variables can be used in numeric expressions Dim balance As Double = 1000 lstBox.Items.Add(1.05 * balance)
declares a variable named varName to be of type Double. Actually, the Dim statement
causes the computer to set aside a location in memory with the name varName. Since
varName is a numeric variable, the Dim statement also places the number zero in that
memory location. (We say that zero is the initial value or default value of the variable.)

184. Assignment Statement
Dim numVar1 As Double = 5 Dim numVar2 As Double = 4 numVar1 = 3 * numVar2 lstBox.Items.Add(numVar1)
declares a variable named varName to be of type Double. Actually, the Dim statement
causes the computer to set aside a location in memory with the name varName. Since
varName is a numeric variable, the Dim statement also places the number zero in that
memory location. (We say that zero is the initial value or default value of the variable.)

185. Incrementing To add 1 to the numeric variable var Or as a shortcut
var = var + 1
Or as a shortcut
var += 1
Or as a generalization
var += numeric expression

186. Built-in Functions Functions return a value Math.Sqrt(9) returns 3
Int(9.7) returns 9
Math.Round(2.7) is 3

187. Integer Data Type
Variables of type Double can be assigned both whole numbers and numbers with decimals
The statement
Dim varName As Integer
declares a numeric variable that can only be assigned whole number values between about -2 billion and 2 billion

188. Multiple Declarations
Dim a, b As Double Two other types of multiple-declaration statements are Dim a As Double, b As Integer Dim c As Double = 2, b As Integer = 5

189. Parentheses
Parentheses should be used liberally in numeric expressions
In the absence of parentheses, the operations are carried out in the following order:
^, * and /, + and -

190. Three Types of Errors
Syntax error
Run-time error
Logic error

191. Some Types of Syntax Errors
Misspellings
lstBox.Itms.Add(3)
Omissions
lstBox.Items.Add(2 + )
Incorrect punctuation
Dim m; n As Integer
Displayed as blue underline in VS

192. A Type of Run-time Error
Dim numVar As Integer = numVar = numVar * numVar What’s wrong with the above?

193. A Logical Error
Dim average As Double Dim m As Double = 5 Dim n As Double = 10 average = m + n / 2 What’s wrong with the above?

194. Error List Window Dim m; n As Double lstResults.Items.Add(5
lstResults.Items.Add(a)

195. – Variables, Input, and Output
3.1 Numbers
3.2 Strings
3.3 Input and Output

196. String Literal "hello" "123-45-6789" "#ab cde?"
A string literal is a sequence of
characters surrounded by quotation marks.
Examples:
"hello"
" "
"#ab cde?"

197. “She said: “I’m tired.””
String Literal
A string literal is a sequence of
characters surrounded by quotation marks.
Examples:
Does this work?
“She said: “I’m tired.””

198. String Variable
A string variable is a name to which a string value can be assigned. Examples: country ssn word firstName

199. String Variable Assignment: firstName = "Fred" Declaration:
Dim firstName As String
Data type
Variable name
Assignment:
firstName = "Fred"

200. Dim firstName As String = "Fred"
String Variable
You can declare a string variable and
assign it a value at the same time.
Dim firstName As String = "Fred"

201. Add Method lstBox.Items.Add(str)
Let str be a string literal or variable. Then,
lstBox.Items.Add(str)
displays the value of str in the list box.

202. String Variable Dim strVar1 As String = "Hello"
You can assign the value of one string variable to another
Dim strVar1 As String = "Hello"
Dim strVar2 As String = "Goodbye"
strVar2 = strVar1
lstOutput.Items.Add(strVar2)

203. Variables and Strings
Private Sub btnDisplay_Click(...) Handles btnDisplay.Click Dim president As String president = "George Washington" lstOutput.Items.Add("president") lstOutput.Items.Add(president) End Sub

204. Option Strict
Visual Basic allows numeric variables to be assigned strings and vice versa, a poor programming practice.
To prevent such assignments, set Option Strict to On in the Options dialog box.

205. Option Strict -continued
Select Options from the Tools menu
In left pane, expand Projects and Solution
Select VB Defaults
Set Option Strict to On

206. Text Boxes for Input & Output
The contents of a text box is always a string
Input example
strVar = txtBox.Text
Output example
txtBox.Text = strVar

207. Data Conversion
Because the contents of a text box is always a string, sometimes you must convert the input or output
dblVar = CDbl(txtBox.Text)
txtBox.Text = CStr(numVar)
Converts a String to a Double
Converts a number to a string

208. Widening and Narrowing
Widening: assigning an Integer value to a Double variable
Widening always works. (Every Integer is a Double.)
No conversion function needed.
Narrowing: assigning a Double value to an Integer variable
Narrowing might not work. (Not every Double is an Integer.)
Narrowing requires Cint.
Will loose information (everything after the decimal place)
Strings can be given a different initial value as follows

209. Auto Correction

210. With Option Strict On Dim dblVar As Double, intVar As Integer
Dim strVar As String
Not Valid: Replace with:
intVar = dblVar intVar = CInt(dblVar)
dblVar = strVar dblVar = CDbl(strVar)
strVar = intVar strVar = CStr(intVar)

211. Combining two strings to make a new string
Concatenation
Combining two strings to make a new string
quote1 = "We'll always "
quote2 = "have Paris."
quote = quote1 & quote2
txtOutput.Text = quote & " - Humphrey Bogart"
Displays
We'll always have Paris. - Humphrey Bogart

212. Appending To append str to the string variable var Or as a shortcut
var = var & str
Or as a shortcut
var &= str

213. Appending Example
Dim var As String = "Good" var &= "bye" txtBox.Text = var

214. String Properties and Methods
"Visual".Length is 6. .length calculates the length of the string. Varname = “blah” Varname.length

215. String Properties and Methods
"Visual".ToUpper is VISUAL .ToUpper makes everything upper case. Varname = “blah”

216. String Properties and Methods
"123 Hike".ToLower is “123 hike” .ToLower makes everything lower case Varname = “Blah”

217. String Properties and Methods
"a" & " bcd ".Trim & "efg" is “abcdefg” .trim removes leading/trailing spaces Varname = “ blah “ Varname.trim

218. String properties Dim varname As String = "Tim Hortons"
Can apply a method onto a method
What does this do?
Dim varname As String = "Tim Hortons"
varname.ToUpper.Replace("I", "O").ToLower()

219. Positions in a String
Positions of characters in a string are numbered 0, 1, 2, …. Consider the string “Visual Basic”. Position 0: V Position 1: i Position 7: B Substring “al” begins at position 4

220. Substring Method
Let str be a string str.Substring(m, n) is the substring of length n, beginning at position m in str “Visual Basic”.Substring(2, 3) ? “Visual Basic”.Substring(0, 1) ?

221. IndexOf Method
Let str1 and str2 be strings. str1.IndexOf(str2) is the position of the first occurrence of str2 in str1 (Note: Has value -1 if str2 is not a substring of str1.) "Visual Basic".IndexOf("is") is 1. "Visual Basic".IndexOf("si") is 9. "Visual Basic".IndexOf("ab") is -1.

222. The Empty String
The string "" (NOT " "), which contains no characters, is called the empty string or the zero-length string
The statement lstBox.Items.Add("") skips a line in the list box
The contents of a text box can be cleared with either the statement
txtBox.Clear()
or the statement
txtBox.Text = ""

223. Initial Value of a String
By default the initial value is Nothing
Strings can be given a different initial value as follows:
Dim name As String = "Fred"

224. Comments
Private Sub btnCompute_Click (...) Handles btnCompute.Click 'Calculate the balance in an account Dim rate As Double 'Annual rate of interest Dim curBalance As Double 'Current balance

225. Internal Documentation
Other people can easily understand the program
You can understand the program when you read it later
Long programs are easier to read because the purposes of individual pieces can be determined at a glance

226. Line-Continuation Character
A long line of code can be continued on another line by using an underscore (_) preceded by a space
msg = "I'm going to make " & _
"him an offer he can't refuse."

227. Scope
The scope of a variable is the portion of the program that can refer to it
Variables declared inside an event procedure are said to have local scope and are only available in the event procedure in which they are declared

228. Scope
Variables declared outside an event procedure are said to have class-level scope and are available to every event procedure.
Usually declared after
Public Class formName
(Declarations section of Code Editor.)

229. Automatic Colorization
Comments – green String literals – maroon Keywords – blue Note: Keywords are words such as Sub, Handles, Private, With, and End that have special meaning in Visual Basic. They cannot be used as variable names.

230. Commenting Commenting is critical For yourself and others
Have to do it right

231. Commenting

232. Commenting

233. Commenting

234. Commenting

235. – Variables, Input, and Output
3.1 Numbers
3.2 Strings
3.3 Input and Output

236. Formatting Output with Functions
String Value
FormatNumber( , 1)
12,345.6
FormatCurrency( , 2)
$12,345.63
FormatPercent(0.183, 0)
18%

237. Formatting Output with Zones
Use a fixed-width font such as Courier New
Divide the characters into zones with a format string.
Dim fmtStr As String = "{0, 15}{1, 10}{2, 8}"
lstOutput.Items.Add(String.Format(fmtStr, _
data0, data1, data2))

238. Formatting Output with Zones
Use a fixed-width font such as Courier New
Divide the characters into zones with a format string.
Dim fmtStr As String = "{0, 15}{1, 10}{2, 8}"
Debug.Print(String.Format(fmtStr, "abc", "def", "ghi"))
 “ abc def ghi”

239. Formatting Output with Zones
Dim fmtStr As String = "{0, -15}{1, 10}{2, 8}" lstOutput.Items.Add(String.Format(fmtStr, _ data0, data1, data2)) Here, 15 was preceded by a minus sign. This produces left justification in 0th zone. There will be right justification in the other two zones.

240. Formatting Output with Zones
Use a fixed-width font such as Courier New
Divide the characters into zones with a format string.
Dim fmtStr As String = "{0,-15}{1, 10}{2, 8}"
Debug.Print(String.Format(fmtStr, "abc", "def", "ghi"))
 “abc def ghi”

241. Reading Data from Files
Data can be stored in text files and accessed with a StreamReader object.
We assume that the text files have one piece of data per line.

242. Sample File: PAYROLL.TXT
Mike Jones John Smith
Name
Hourly wage
Number of hours worked

243. Steps to Use StreamReader
Execute a statement of the form
Dim readerVar As IO.StreamReader = _
IO.File.OpenText(filespec)
or the pair of statements
Dim readerVar As IO.StreamReader
readerVar = IO.File.OpenText(filespec)
1. Execute a statement of the form
Dim readerVar As IO.StreamReader
A StreamReader is an object from the Input/Output class that can read a stream of
characters coming from a disk or coming over the Internet. The Dim statement
declares the variable readerVar to be of type StreamReader.
2. Execute a statement of the form
readerVar = IO.File.OpenText(filespec)
where filespec identifies the file to be read. This statement establishes a communi-cations
link between the computer and the disk drive for reading data from the disk.
Data then can be input from the specified file and assigned to variables in the pro-gram.
This assignment statement is said to “open the file for input.”
Just as with other variables, the declaration and assignment statements in Steps
2 and 3 can be combined into the single statement
Dim readerVar As IO.StreamReader = IO.File.OpenText(filespec)
3. Read items of data in order, one at a time, from the file with the ReadLine method.
Each datum is retrieved as a string. A statement of the form
strVar = readerVar.ReadLine
causes the program to look in the file for the next unread line of data and assign it
to the variable strVar. The data can be assigned to a numeric variable if it is first
converted to a numeric type with a statement such as
numVar = CDbl(readerVar.ReadLine)
Note: If all the data in a file have been read by ReadLine statements and another item
is requested by a ReadLine statement, the item retrieved will have the value Nothing.
4. After the desired items have been read from the file, terminate the communications
link set in Step 3 with the statement
readerVar.Close()

244. Steps to Use StreamReader
Read items of data in order, one at a time,
from the file with the ReadLine method.
strVar = readerVar.ReadLine
After the desired items have been read from
the file, terminate the communications link
readerVar.Close()
1. Execute a statement of the form
Dim readerVar As IO.StreamReader
A StreamReader is an object from the Input/Output class that can read a stream of
characters coming from a disk or coming over the Internet. The Dim statement
declares the variable readerVar to be of type StreamReader.
2. Execute a statement of the form
readerVar = IO.File.OpenText(filespec)
where filespec identifies the file to be read. This statement establishes a communi-cations
link between the computer and the disk drive for reading data from the disk.
Data then can be input from the specified file and assigned to variables in the pro-gram.
This assignment statement is said to “open the file for input.”
Just as with other variables, the declaration and assignment statements in Steps
2 and 3 can be combined into the single statement
Dim readerVar As IO.StreamReader = IO.File.OpenText(filespec)
3. Read items of data in order, one at a time, from the file with the ReadLine method.
Each datum is retrieved as a string. A statement of the form
strVar = readerVar.ReadLine
causes the program to look in the file for the next unread line of data and assign it
to the variable strVar. The data can be assigned to a numeric variable if it is first
converted to a numeric type with a statement such as
numVar = CDbl(readerVar.ReadLine)
Note: If all the data in a file have been read by ReadLine statements and another item
is requested by a ReadLine statement, the item retrieved will have the value Nothing.
4. After the desired items have been read from the file, terminate the communications
link set in Step 3 with the statement
readerVar.Close()

245. Example using StreamReader
Mike Jones
9.35 35
John Smith
10.75 33
Dim name As String
Dim wage, hours As Double
Dim sr As IO.StreamReader = _
IO.File.OpenText("PAYROLL.TXT")
name = sr.ReadLine
wage = CDbl(sr.ReadLine)
hours = CDbl(sr.ReadLine)
lstBox.Items.Add(name & ": " & wage * hours)
OUTPUT: Mike Jones:
1. Execute a statement of the form
Dim readerVar As IO.StreamReader
A StreamReader is an object from the Input/Output class that can read a stream of
characters coming from a disk or coming over the Internet. The Dim statement
declares the variable readerVar to be of type StreamReader.
2. Execute a statement of the form
readerVar = IO.File.OpenText(filespec)
where filespec identifies the file to be read. This statement establishes a communi-cations
link between the computer and the disk drive for reading data from the disk.
Data then can be input from the specified file and assigned to variables in the pro-gram.
This assignment statement is said to “open the file for input.”
Just as with other variables, the declaration and assignment statements in Steps
2 and 3 can be combined into the single statement
Dim readerVar As IO.StreamReader = IO.File.OpenText(filespec)
3. Read items of data in order, one at a time, from the file with the ReadLine method.
Each datum is retrieved as a string. A statement of the form
strVar = readerVar.ReadLine
causes the program to look in the file for the next unread line of data and assign it
to the variable strVar. The data can be assigned to a numeric variable if it is first
converted to a numeric type with a statement such as
numVar = CDbl(readerVar.ReadLine)
Note: If all the data in a file have been read by ReadLine statements and another item
is requested by a ReadLine statement, the item retrieved will have the value Nothing.
4. After the desired items have been read from the file, terminate the communications
link set in Step 3 with the statement
readerVar.Close()

246. Comment on Example Consider The ampersand automatically converted
lstBox.Items.Add(name & ": " & wage * hours)
The ampersand automatically converted
wage * hours into a string before concatenating.
We didn’t have to convert wage * hours with CStr.
1. Execute a statement of the form
Dim readerVar As IO.StreamReader
A StreamReader is an object from the Input/Output class that can read a stream of
characters coming from a disk or coming over the Internet. The Dim statement
declares the variable readerVar to be of type StreamReader.
2. Execute a statement of the form
readerVar = IO.File.OpenText(filespec)
where filespec identifies the file to be read. This statement establishes a communi-cations
link between the computer and the disk drive for reading data from the disk.
Data then can be input from the specified file and assigned to variables in the pro-gram.
This assignment statement is said to “open the file for input.”
Just as with other variables, the declaration and assignment statements in Steps
2 and 3 can be combined into the single statement
Dim readerVar As IO.StreamReader = IO.File.OpenText(filespec)
3. Read items of data in order, one at a time, from the file with the ReadLine method.
Each datum is retrieved as a string. A statement of the form
strVar = readerVar.ReadLine
causes the program to look in the file for the next unread line of data and assign it
to the variable strVar. The data can be assigned to a numeric variable if it is first
converted to a numeric type with a statement such as
numVar = CDbl(readerVar.ReadLine)
Note: If all the data in a file have been read by ReadLine statements and another item
is requested by a ReadLine statement, the item retrieved will have the value Nothing.
4. After the desired items have been read from the file, terminate the communications
link set in Step 3 with the statement
readerVar.Close()

247. Getting Input from an Input Dialog
stringVar = InputBox(prompt, title)
fileName = InputBox("Enter the name " _
& "of the file containing the " & _
"information.", "Name of File")
Title
Prompt

248. Using a Message Box for Output
MessageBox.Show(prompt, title) MessageBox.Show("Nice try, but no cigar.", _ "Consolation")
Title
MsgBox(prompt, , title)
is executed, where prompt and title are strings, a message dialog box appears with prompt
displayed and the title bar caption title and stays on the screen until the user presses
Enter, clicks on the box in the upper-right corner, or clicks OK. For instance, the state-ment
MsgBox("Nice try, but no cigar.", , "Consolation")
Prompt

249. Masked Text Box Control
Similar to an ordinary text box, but has a Mask property that restricts what can be typed into the masked text box.
Tasks button

250. Masked Text Box Control
Click the Tasks button to reveal Set Mask property.
Click Set Mask to invoke Input Mask dialog box.

251. Input Mask Dialog Box

252. 0 Placeholder for a digit. L Placeholder for a letter.
Mask
A Mask setting is a sequence of characters, with 0, L, and & having special meanings.
0 Placeholder for a digit.
L Placeholder for a letter.
& Placeholder for a character

253. State abbreviation: LL Phone number: 000-0000
Sample Masks
State abbreviation: LL
Phone number:
Social Security Number:
License plate: &&&&&&