1. Intro to Programming and Visual Basic .NET
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2. Program Set of instructions a computer follows to perform a task
Examples
Calculate gross pay, taxes, and net pay
Print past-due notices to credit card holders
Drop the lowest homework assignment score
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3. Computer Programs Used in most industries Accounting Human Resources
Education
Aviation
Marketing
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4. Program Acquisition Shrink-Wrap Software In-house Development
Very available
Lower cost
Standardized, not customizable
In-house Development
Higher cost
Customizable to specific needs
Outsourcing
Customizable
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5. Methods of Programming
Procedural
Statements executed by the computer, one after another, in sequential order from start to termination of a program
Typical of text-based terminal
User responds to program
Object-Oriented
GUI interface consisting of a set of objects
Program responds to user
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6. Procedural Program Example
Display onscreen message: "How many hours did you work?"
Allow the user to enter the number of hours worked
Once the user enters a number, store it in memory
Display onscreen message: “What is your hourly pay rate?"
Allow the user to enter an hourly pay rate
Multiply the two numbers stored in memory and store the result in memory
Display a message on the screen that shows the gross pay. The message must include the result of the calculation performed in step 7
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7. Procedural Program Example
How many hours did you work? 10
What is your hourly pay rate? 15
Your gross pay is $150.00
C>_
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8. Object-Oriented Programming (OOP)
Centered on object creation.
Object: element containing data & actions
Examples
Form (window) object
Label (descriptions) object
Text Box (data entry) object
Button (event driven) object
Attributes (Properties)
Text property (e.g., Hourly Pay Rate)
Size (Height & Width)
Location (Vertical & Horizontal Position)
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9. Event-Driven Programming
Responds to events
Action or occurrence that takes place in the program.
User Action Examples
Click or double-click a button
Press a key on the keyboard
System Occurrences Examples
Timer
Sits idle until an event occurs—again program responds to user (or system).
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10. Events Button Object (Control) responds to a Click event.
Text Box Object (Control) responds to data entry, which is a TextChanged event.
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11. Event Procedure Algorithm that executes when the event occurs.
Not triggered until event occurs.
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12. Algorithm* Formula or set of steps for solving a particular problem
Characteristics:
Unambiguous
Well-defined
Clear
Fewest steps possible
Terminal
*Adapted from webopedia.com’s definition.
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13. Algorithm Example *Example for algorithm definition on webopedia.com.
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14. Pseudocode* Outline of a program No real formatting or syntax rules
Cross between human language and programming language.
Human readable
Basis for algorithm development
No real programming language skills needed
*Adapted from webopedia.com’s definition and Gaddis’ definition.
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15. Pseudocode Example Store hours worked from user input into memory
Store hourly pay rate from user input into memory
Multiply value of hours worked (in memory) by the hourly pay rate (in memory)*
Store result into memory
Display result (in memory) as output
*Simple gross pay calculation ignoring overtime rates.
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16. Controls (Objects) Control Prefix Example Description Form frm frmMain
GUI interface
Button
btn
btnClose
Rectangular object that triggers event procedure when clicked
Label
lbl
lblGrossPay
Box displaying text that user can’t change (descriptions & output)
Text
txt
txtPayRate
Rectangular area for data input by user
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17. Control Prefixes (p. 9) chk Check Box cbo Combo Box btn Button
frm Form
grp Group Box
lbl Label
lst List Box
mnu Menu
rad Radio Button
pic Picture Box
txt Text Box
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18. Download Student Chapter 1 Files
Run Program2\bin\Program2.exe
See p. 10
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19. Measures of Quality Must fulfill users’ needs.
Include required functionality.
Perform functions correctly.
Should be easy to use with little training.
Design for clarity.
Should be understandable looking at coding.
Should have flexibility integrated for future versions of application.
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20. System Development Life Cycle
Involves joint effort of users & programmers.
Identify user requirements.
Design the application.
Construct the application.
Implement the system.
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21. Step 1: Identify User Requirements
Review request forms from users.
Communicate with users.
Identify current problems & concerns.
Determine users’ needs:
Features
Method of operation
Obtain contract if you are the outsource for another organization.
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22. Step 1, continued Clearly define what the program should do. Purpose
To calculate the user’s gross pay.
Input
# of hours worked
Hourly pay rate
Process
Multiply # of hours worked by the hourly pay rate to obtain gross pay.
Output
Display a message indicating the user’s gross pay.
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23. Step 2: Design (Plan) the Application
Create blueprint of application.
Sketch components for each user interface, similar to storyboarding.
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24. Step 2, continued
List needed controls (text boxes, labels, & buttons).
Specify properties/attributes (Text) for each control.
Specify methods/events (Click) for each control.
Write pseudocode &/or flowchart
Show design to users & obtain their feedback (very critical).
Revise design based on feedback and continue cycle of user input.
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25. Step 2 (List Controls Needed)
Type Name Description
TextBox txtHoursWorked Allows the user to enter the number of hours worked.
TextBox txtPayRate Allows the user to enter the hourly pay rate
Label lblGrossPay Displays the gross pay, after the btnCalcGrossPay
button has been clicked
Button btnCalcGrossPay When clicked, multiplies the number of hours worked
by the hourly pay rate
Button btnClose When clicked, terminates the application
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26. Step 2 (Define Control Property Values)
Property—characteristic, such as control name
Value—specific attribute, such as lblGrossPay
Control Type Control Name Text
Form (Default) "Wage Calculator"
Label (Default) "Number of Hours Worked"
Label (Default) "Hourly Pay Rate"
Label (Default) "Gross Pay Earned"
Label lblGrossPay "$0.00"
TextBox txtHoursWorked ""
TextBox txtPayRate ""
Button btnCalcGrossPay "Calculate Gross Pay"
Button btnClose "Close"
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27. Step 2 (List Methods for Controls)
Methods—specific actions to perform based on specific user action, such as mouse click
Method Description
btnCalcGrossPay_Click Multiplies the number of hours worked by the
hourly pay rate
These values are entered into the
txtHoursWorked and txt-PayRate TextBoxes
The result is stored in the lblGrossPay Text
property
btnClose_Click Terminates the application
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28. Step 2 (Write Pseudocode)
Create a pseudocode version of each method:
Pseudocode is a combination of English and a programming language
Critical to effect planning; saves valuable time when you start actual programming; minimizes errors as you program.
For this application: Store Number of Hours Worked times Hourly Pay Rate in grossPay. Store the value in grossPay in lblGrossPay.Text.
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29. Step 2 (Continued) Check the code for errors:
Go step by step through the code, running it in your head as though the computer is running it.
Keep track of where in the code is being executed.
Keep track of the values of all of the variables.
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30. Begin Program Input hourly rate Input # of hours worked
Are the # of hours > 40? No
Multiply the hours worked by the hourly rate.
Yes
Multiply 40 by the hourly rate to get the regularly weekly pay.
Subtract 40 from the total hours worked to find the OT hours.
Multiply the pay rate by 1.5 to get the OT rate.
Multiply the OT hours by the OT rate to get the amount of OT pay.
Add the regular weekly pay and the OT pay.
Display gross pay
End Program
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31. Begin Program Input hourly rate Input # of hours worked
Are the # of hours > 40? No
Multiply the hours worked by the hourly rate.
Yes
Multiply 40 by the hourly rate to get the regularly weekly pay.
Subtract 40 from the total hours worked to find the OT hours.
Multiply the pay rate by 1.5 to get the OT rate.
Multiply the OT hours by the OT rate to get the amount of OT pay.
Add the regular weekly pay and the OT pay.
Display gross pay
End Program
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32. Step 3: Construct the Application
Use VB to create the application.
Create one piece (form) at a time.
Create form (user interface window) and set its properties.
Insert controls based on design specs.
Set properties for all controls.
Write code for the event procedures.
Use pseudocode to create event procedures into correct syntax.
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33. Step 3 (continued) Run the program.
Test and debug the application throughout development.
Correct syntax errors, incorrect use of the language, such as keyword.
Correct logic errors, errors that don’t crash the program but produce inaccurate results, such as adding instead of multiplying.
Use various examples of test data (different numbers, names, etc.).
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34. Getting Started Create folder on H drive: ISYS1200
Create subfolders w/ in ISYS1200
Practice
Assignments
Slide Shows
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35. Visual Basic .NET Interface
Start program (see p. 22).
Specify folder and subfolder location (Location text box).
Type program name (Name text box).
Chapter1GrossPay
MulberyAssignment1 (for assignments)
Folder created within location
based on project name typed
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36. Project Numerous files to run program
Keep in same folder; do not copy/paste program files.
Can copy/paste image files (bmp) into project folder if need images
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37. Visual Basic .NET Environment
Project name
Mouse
over to
see Toolbox
Design window
(displays form)
Form(s) within
Solution Explorer
Form
(interface)
Property window
for selected object
(currently the form)
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38. Design Window Application’s forms Area where you design the interface
Grid visible for programmer (not user)
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39. Solution Explorer Window
Solution (container for storing project files)
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40. Properties Window Displays settings for currently selected object
Changes based on what is selected
Currently shows properties for form object
Second example when a Label control object is selected
Note:
Some properties set at Design Time in Properties window.
Other properties set with programming code.
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41. Form Properties Text StartPosition MaximizeBox and MinimizeBox Icon
Appears on title bar
StartPosition
Form location onscreen
WindowsDefault (default setting)
CenterScreen (typical)
MaximizeBox and MinimizeBox
True (Default)
False (Dims or hides)
Icon
Symbol in top left corner (left of Text property)
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42. ToolBox
Unpinned
Pinned (stays onscreen)
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43. Textbook Reference USE IT—YOU PAID FOR IT!!!!
Read information (pp ).
Complete tutorials (pp ).
Answer Check Points (p. 34).
Check answers in back of book (p. 819)
Note key terms (pp )
Answer Review Questions (pp ).
Sometimes these make good test questions!
Check answers from ftp site
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44. Reminder Send e-mail to mulberke@uvsc.edu by 5 p.m. today (January 8).
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