Transcript Visual Basic Application

Problem
 Create a Windows-based application that will calculate
the Gross Pay earned for a worker, given the number of
hours worked and hourly pay rate.
Problem Solving
 Input (controls):
 Hours Worked
 Hourly Pay Rate
 Process (event handling):
 Calculate Gross Pay

Gross Pay = hoursWorked * hourlyPayRate
 Output (controls):
 Gross Pay
Creating the Visual Basic Application
 Event Driven Programming
 Create the Interface / Window first


Input
Output
 Then Code the Application


Process
Event Handing Methods
Creating the Interface
 Input
 Hours Worked  Textbox, Label
 Hourly Pay Rate  Textbox, Label
 Output
 Gross Pay Earned  Label (title), Label (display info)
 Events
 Calculate Gross Pay  Button
 Exit Program  Button
Design the Interface – TOE Chart
Task (T)
Object (O)
Event (E)
Input Hours Worked
Textbox, Label
None
Input Pay Rate
Textbox, Label
None
Output Gross Pay
Label (display), Label
(title)
None
Calculate Gross Pay
Button
Click
Exit Program
Button
Click
Create Your Interface
Label
Label
Label
2 Buttons
Text Box
Text Box
Label
Properties
 Form1
 Name = frmWageCalculator
 Text = “Wage Calculator”
 Label1
 No Need to Rename (Display Only – will not use)
 Text = “Number of Hours Worked”
 Label2
 No Need to Rename (Display Only)
 Text = “Hourly Pay Rate”
 Label3
 No Need to Rename (Display Only)
 Text = “Gross Pay Earned”
Properties
 Textbox1
 Name: txtHoursWorked
 Text: <blank>
 Textbox2
 Name: txtPayRate
 Text: <blank>
 Label4




Name: lblGrossPay (needs name because will will use this label)
Text: <blank>
Autosize: Off
BorderStyle: FixedSingle
 Button1
 Name: btnCalculate
 Text: “&Calculate Gross Pay”
 Button2
 Name: btnExit
 Text: “E&xit”
Process – Event Handling
 btnCalculate
 Button Click Event
 Assignment statement
 Gets the data from the text field of the txtHoursWorked textbox and
the txtPayRate textbox.
 Assign the calculation data from the textboxes into the lblGrossPay
text field
 Val changes the text input from the text box into a number
Event Handling
 btnExit
 Button Click Event
 End
Run & Test Program
 Syntax Errors – Language Errors
 Caught by the Compiler & Interpreter
 Visual Basic – wavy line under problem code
 Run-Time Errors
 Causes Program to Crash
 Logic Errors
 Program Runs but gets “Wrong Answer”
Run & Test Program
 Must test for expected and unexpected input
Homework
 Create a “Multiplication Tables” application. The
program should allow the user to input 2 numbers and
then display the product of those 2 numbers.
(Remember to use the val function)