1. COPYRIGHT 2007: Dr. David Scanlan, CSUS 010-HELLO WORLD VB-Express.ppt Purpose: A "Hello World" program's purpose is to eliminate as much complexity as possible so that students successfully write and run their first program. What these slides cover: --How to write a simple program. --How to reduce the complexity of the IDE --How to place objects on a form --How to use the Toolbox --How to use a Textbox for output --How to use a Button --How to run a program --How to save a program 010-HELLO WORLD VB-Express.ppt Slide 1- 1

2. COPYRIGHT 2007: Dr. David Scanlan, CSUS OBJECTIVES: To get started immediately so that you get the "big" picture right away. This will make VB 2008.NET textbook easier to understand. To reduce the complexity of the IDE. IDE: Integrated Development Environment. To quickly show how easy it is to write a simple program in VB 2008.NET. The program will illustrate: the use of the Toolbox, the use of a Textbox for output. the use of a Button, and the output of the words "Hello World" in a Textbox when a button is pressed. To learn how to save a program. FIRST PROGRAM: HELLO WORLD VB Express Slide 1- 2

3. COPYRIGHT 2007: Dr. David Scanlan, CSUS NOTE: This program uses the default names for your button, label, textbox and form: button1, label1, textbox1 and form1. These names were not changed in order to make the following program as simple as possible. Later, we will make the names of buttons, labels, etc much more meaningful. FIRST PROGRAM: HELLO WORLD VB Express Slide 1- 3

4. COPYRIGHT 2007: Dr. David Scanlan, CSUS Dr. Scanlan: Program this with the class following. Use 18 point font for the code. HELLO WORLD PROGRAM LABEL TEXTBOX BUTTON: Press the button and "Hello World appears in the LABEL and in the TEXTBOX.

5. COPYRIGHT 2007: Dr. David Scanlan, CSUS FIRST PROGRAM: HELLO WORLD VB Express Requirements When you start VB Express, the Screen will look like this. Click here to create a Project (a program) Slide 1- 5

6. COPYRIGHT 2007: Dr. David Scanlan, CSUS FIRST PROGRAM: HELLO WORLD VB Express Select this This is not a very meaningful name for the Project. See next slide. Slide 1- 6

7. COPYRIGHT 2007: Dr. David Scanlan, CSUS FIRST PROGRAM: HELLO WORLD VB Express Hello World is a much more meaningful name for this Project. Enter Hello World here. Next, press OK Slide 1- 7

8. COPYRIGHT 2007: Dr. David Scanlan, CSUS FIRST PROGRAM: HELLO WORLD VB Express Your Screen should now look like this. Click on Data Sources. We are going to get if off the screen because we will not be using it in this course. Slide 1- 8

9. COPYRIGHT 2007: Dr. David Scanlan, CSUS FIRST PROGRAM: HELLO WORLD VB Express Your screen should now look like this. Click on the “x” to get the Data Source window off the screen. We did this to simplify the IDE (Integrated Development Environment. Slide 1- 9

10. COPYRIGHT 2007: Dr. David Scanlan, CSUS FIRST PROGRAM: HELLO WORLD VB Express Your screen should now look like this. We will use these two windows a lot during this semester. 1.Solution Explorer Window 2.Properties Window Slide 1- 10

11. COPYRIGHT 2007: Dr. David Scanlan, CSUS FIRST PROGRAM: HELLO WORLD VB Express Place the cursor on the Toolbox Tab to cause the tools to be displayed. Note: If you move the cursor away from the Tab, the tools will disappear. Only the Tab will remain. You can keep the Toolbox in view if you click on the horizontally oriented pin. See next slide. Slide 1- 11

12. COPYRIGHT 2007: Dr. David Scanlan, CSUS FIRST PROGRAM: HELLO WORLD VB Express Note the vertical orientation of the pin. The Toolbox is now “pinned down”. Slide 1- 12

13. COPYRIGHT 2007: Dr. David Scanlan, CSUS FIRST PROGRAM: HELLO WORLD VB Express Next, select a Button from the ToolBox and place it on the form. There are two ways to place a Button on the form: 1.Double Click on the Button. 2.Click on the Button and drag it onto the form. Slide 1- 13

14. COPYRIGHT 2007: Dr. David Scanlan, CSUS FIRST PROGRAM: HELLO WORLD VB Express Place the button about here Next, place a Textbox on the form using the same procedure you used for the Button. Slide 1- 14

15. COPYRIGHT 2007: Dr. David Scanlan, CSUS FIRST PROGRAM: HELLO WORLD VB Express The form should now look like this. Form Button Textbox Note: a Textbox can be used to display data or to input data into the program. Slide 1- 15

16. COPYRIGHT 2007: Dr. David Scanlan, CSUS FIRST PROGRAM: HELLO WORLD VB Express Double click on the button to produce a “Click Event” in the code view where we do our code programming. See next slide. Slide 1- 16

17. COPYRIGHT 2007: Dr. David Scanlan, CSUS FIRST PROGRAM: HELLO WORLD VB Express Your screen should now look like this. We will place our code here. See next slide. Slide 1- 17

18. COPYRIGHT 2007: Dr. David Scanlan, CSUS FIRST PROGRAM: HELLO WORLD VB Express Object Property Data Code View Tab Design View Tab Now run the program by pressing here. See next slide. Slide 1- 18

19. COPYRIGHT 2007: Dr. David Scanlan, CSUS FIRST PROGRAM: HELLO WORLD VB Express Your program should now look like this. Next, press the button and watch “Hello World” get displayed in the Textbox. Slide 1- 19

20. COPYRIGHT 2007: Dr. David Scanlan, CSUS FIRST PROGRAM: HELLO WORLD VB Express After pressing the button while the program is running, Hello World is displayed in the Textbox. Slide 1- 20

21. COPYRIGHT 2007: Dr. David Scanlan, CSUS FIRST PROGRAM: HELLO WORLD VB Express An easy way to stop the program is to press the “x” Slide 1- 21

22. COPYRIGHT 2007: Dr. David Scanlan, CSUS FIRST PROGRAM: HELLO WORLD VB Express An easy way to exit Visual Basic 2008 Express is to press this “x” Slide 1- 22

23. COPYRIGHT 2007: Dr. David Scanlan, CSUS FIRST PROGRAM: HELLO WORLD VB Express If you want to save your Project, then choose Save. Slide 1- 23

24. COPYRIGHT 2007: Dr. David Scanlan, CSUS FIRST PROGRAM: HELLO WORLD VB Express Project name Solution Name Solution files can contain several projects. In this course we will have only one project. I would change the location to something easy to remember. How about C:\MIS 15? See next slide. Slide 1- 24

25. COPYRIGHT 2007: Dr. David Scanlan, CSUS FIRST PROGRAM: HELLO WORLD VB Express Slide 1- 25

26. COPYRIGHT 2007: Dr. David Scanlan, CSUS FIRST PROGRAM: HELLO WORLD VB Express Your project has now been saved on your hard drive: C:\MIS 15\Hello World Take a look, it is there. Slide 1- 26

27. HELLO WORLD PROGRAM LABEL TEXTBOX Add a LABEL just for practice

28. COPYRIGHT 2007: Dr. David Scanlan, CSUS FIRST PROGRAM: HELLO WORLD VB Express Congratulations! You just wrote your first Visual Basic 2008 Program. Slide 1- 28

29. How to Reset the IDE back to the original settings. Slide 1- 29

30. If your IDE looks like this and you want to reset it. Follow the next slides… Slide 1- 30

31. Click here. Slide 1- 31

32. Click here. Slide 1- 32

33. Click here. Slide 1- 33

34. Click here. Slide 1- 34

35. Click here. Slide 1- 35

36. The IDE has been restored to its original settings. Note: The Data Sources Tab is now present. The End Slide 1- 36

37. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley STARTING OUT WITH Visual Basic 2008 Slide 1- 37 FOURTH EDITION Tony Gaddis Haywood Community College Kip Irvine Florida International University Slide 1- 37

38. COPYRIGHT 2007: Dr. David Scanlan, CSUS This OOP stuff is easy once you get some practice. A GENTLE INTRODUCTION TO OBJECT-ORIENTED PROGRAMMING (OOP)TERMS AND CONCEPTS. Slide 1- 38

39. COPYRIGHT 2007: Dr. David Scanlan, CSUS OBJECTIVES To gain a very basic understanding of Object Oriented Programming (OOP) terms and concepts using examples from everyday life. These are the main OOP terms that we will cover: CLASS (CODE that is COPIED in order to create an object) PROPERTIES ( also called ATTRIBUTES) BEHAVIORS (also called METHODS) OBJECT (The copied code from a class) INSTANTIATION (The process of CREATING an object) INSTANCE(An OBJECT created from a class) INHERITANCE (Covered later in the course) POLYMORPHISM ( Covered later in the course) ENCAPSULATION (Covered later in the course) These OOP terms and concepts will be learned using everyday items like washing machines, caster wheels, and nerds. Actual OO computer programming will delayed until you get a good understanding of its terms and concepts. Slide 1- 39

40. COPYRIGHT 2007: Dr. David Scanlan, CSUS The Nerd CLASS CLASS = TEMPLATE = BLUEPRINT = MODEL A CLASS is easy to understand if you think of it as a TEMPLATE, a BLUEPRINT, or a MODEL. In my opinion, the word CLASS, was a poor choice for this concept: Template or blueprint would have been a better choice. Slide 1- 40

41. COPYRIGHT 2007: Dr. David Scanlan, CSUS NERD CLASS CLASS This is a CLASS (or template) called NERD. This object has PROPERTIES and BEHAVIORS. Nerd CLASS name PROPERITES BEHAVIORS or METHODS Smart Thin Social clod Hair color etc... Read book Turn on computer Type on keyboard Chew pizza Put pencil in pocket protector etc... The Nerd CLASS CLASS = TEMPLATE = BLUEPRINT = MODEL Think of this as template for making more nerds. Slide 1- 41

42. COPYRIGHT 2007: Dr. David Scanlan, CSUS 1.6 Concepts In OOP: Object Using the template, we can create as many new OBJECTS as we want. OBJECT If we select one of these items in the CLASS as a template for creating another, we call the new one an OBJECT. Let’s choose this model as a template from which to create new nerds. NERD CLASS The Nerd CLASS CLASS = TEMPLATE = BLUEPRINT = MODEL Think of this as template for making more nerds. Slide 1- 42

43. COPYRIGHT 2007: Dr. David Scanlan, CSUS OOP for Nerds VB.NET “I was INSTANTIATED by accident. Yes, I admit it, I am an OBJECT from the nerd CLASS. You can even call me an INSTANCE from the nerd CLASS. Slide 1- 43

44. COPYRIGHT 2007: Dr. David Scanlan, CSUS The Nerd CLASS CLASS = TEMPLATE = BLUEPRINT = MODEL A CLASS is easy to understand if you think of it as a TEMPLATE, a BLUEPRINT, or a MODEL. In my opinion, the word CLASS, was a poor choice for this concept: Template or blueprint would have been a better choice. Slide 1- 44

45. COPYRIGHT 2007: Dr. David Scanlan, CSUS What is a class in Visual Basic? A Class is simply previously written code with 1.Properties 2.Methods (also called Behaviors) An Object is a copy of the Class code with the same 1.Properties 2.Methods NOTE: WE CAN MAKE AS MANY COPIES (OBJECTS) OF A CLASS AS WE WANT. Example: The items in the Toolbox such as Button, Labels, Textboxes, etc. are classes. When we click on a class, we put a copy of the class's code onto the Form. Instructor: Give demo. Use Toolbox and create OBJECTS from CLASSES. CLASSESOBJECTS Slide 1- 45

46. Chapter Introduction to Programming and Visual Basic 2008 Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 1 Slide 1- 46

47. Computer Systems: Hardware and Software Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 1.1 DR SCANLAN: SKIP PART 1.1AND JUMP DIRECTLY TO PART 1.2 IT IS ASSUMED THAT STUDENTS KNOW PART 1.1 FROM 1A, 1B, AND 1C Slide 1- 47

48. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Refers to the physical components Not one device but a system of many devices Major types of components include: Central Processing Unit Main memory Secondary storage devices Input devices Output devices Computer Hardware Slide 1- 48

49. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Organization of a Computer System Slide 1- 49

50. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Fetches instructions from main memory Carries out the operations commanded by the instructions Each instruction produces some outcome CPU gets instructions from a program A program is an entire sequence of instructions Instructions are stored as binary numbers Binary number - a sequence of 1’s and 0’s The CPU Slide 1- 50

51. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Commonly known as random access memory, or just RAM Holds instructions and data needed for programs that are currently running RAM is usually a volatile type of memory Contents are lost when power is turned off Used as temporary storage Main Memory Slide 1- 51

52. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley A nonvolatile storage medium Contents retained while power is off Hard disk drives are most common Records data magnetically on a circular disk Provides fast access to large amounts of data Optical devices store data on CD’s as pits USB flash memory devices High capacity device plugs into USB port Portable, reliable, and fits easily in a pocket Secondary Storage Slide 1- 52

53. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Any type of device that provides data to a computer from the outside world For example: Keyboard Mouse Scanner Input Devices Slide 1- 53

54. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Any type of device that provides data from a computer to the outside world Examples of output data: A printed report An image such as a picture A sound Common output devices include: Monitor (display screen) Printer Output Devices Slide 1- 54

55. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley The programs that run on a computer Two major categories Operating systems Controls the processes within the computer Manages the computer's hardware devices Application Software Solve problems or perform tasks needed by users Examples include word processing, spreadsheets, games, Internet browsers, playing music, etc) Each program is referred to as an application This book develops applications in Visual Basic Software Slide 1- 55

56. Programs and Programming Languages Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 1.2 A Program Is a Set of Instructions a Computer Follows in Order to Perform a Task A Programming Language Is a Special Language Used to Write Computer Programs

57. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Computers only follow instructions. A computer program is a set of instructions to the computer. For example, a program to compute gross pay. We must program the steps. Steps>> Next slide What Is a Program? Slide 1- 57

58. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 1. Display message: “Hours worked?" 2. User enters hours 3. Put hours in memory 4. Display message: “Pay Rate?" 5. User enters pay rate 6. Store pay rate in memory 7. GrossPay = Hours * Rage 8. Display Gross Pay Algorithm = steps for solving a problem. Example: a recipe for baking a cake Computing Gross Pay Slide 1- 58 STEPS:

59. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Wage Calculator Slide 1- 59 btnCalcGrossPaybtnClose txtHoursWorked txtPayRate lblGrossPay Label1 Label2 Label3  The label controls use the default names (Label1, Textbox1, Button1, Form1, etc.)  Text boxes, buttons, and the Gross Pay label play an active role in the program and have been changed Dr. Scanlan: Program this with the class following. 18 point text for the code.

60. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Memory snapshots show states of the program 3. Store hours worked in memory 6. Store hourly pay rate in memory 7. Multiply hours worked by pay rate and store amount earned in memory States and Transitions Slide 1- 60 Program Starting State hours worked hourly pay rate amount earned ?? Snapshot after Step 3 hours worked hourly pay rate amount earned 20 ?? Snapshot after Step 6 hours worked hourly pay rate amount earned 20 25 ?? Snapshot after Step 7 hours worked hourly pay rate amount earned 20 25 500

61. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley What the computer understands: Binary Numbers 1001 0111 0111 0110 The CPU processes instructions as a series of 1’s and 0’s called machine language Programming languages allow us to use words instead of a series of 1’s and 0’s Compilers (software) translate VB statements into machine language, so the computer can understand the VB statements (code). Programming Languages Slide 1- 61 ~0 volts ~5 volts

62. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Common Programming Languages Visual Basic Python Javascript Java C# C C++ PHP Slide 1- 62 Visual Basic is a: programming language programming environment with tools to: Create objects on forms, etc. Write programming language statements

63. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Visual Basic is event-driven An event is an action that takes place within a program. Clicking a button (a Click event). Visual Basic controls (buttons, textboxes, etc.) are capable of detecting many, many events. A program can respond to an event if the programmer writes an event procedure. See Next Slide>> Event Driven Programming: Events Slide 1- 63

64. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Event Driven Programming: Events Slide 1- 64 When announced, this program will be written in the lab with no notes. You must practice writing this program. Steps: 1.Create Form1 VERY similar to the one shown. 2.Set FORM1’s text property to: Wage Calculator 3.Set these three labels’ text properties to their indicated values. Set the name property of the fourth label with $150.00 to: lblDisplayGrossPay 4.Place the two buttons on Form1 -Set text property of one button to: Calculate Gross Pay -Set text property of the second button to: Close -Set the Name Property of button Calculate Gross Pay to: btnCalculateGrossPay 5.Double click on the CalculateGrossPay button. You should see the following: Public Class Form1 Private Sub btnCalculateGrossPay_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCalculateGrossPay.Click End Sub End Class

65. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Event Driven Programming: Events Slide 1- 65 When announced, this program will be written in the lab with no notes. You must practice writing this program. Steps: 6.Double click on the Close button. You should see the following: Public Class Form1 Private Sub btnCalculateGrossPay_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCalculateGrossPay.Click End Sub Private Sub btnClose_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnClose.Click End Sub End Class 7.You have just created two click events, but you now need to place code into these two events. Place code here

66. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Event Driven Programming: Events Slide 1- 66 When announced, this program will be written in the lab with no notes. You must practice writing this program. Steps: 8.Finish the program using the code below: 9.Run the program. 10.Check to be sure the results are correct. Public Class Form1 Private Sub btnCalculateGrossPay_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCalculateGrossPay.Click lblDisplayGrossPay.Text = FormatCurrency(CDec(txtHourlyRate.Text) * CDec(txtHoursWorked.Text)) End Sub Private Sub btnClose_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnClose.Click Me.Close() End Sub End Class

67. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Event Driven Programming: Events Slide 1- 67 Event Procedure triggered by a Click Event -- Pressing the Calculate Gross Pay button triggers a click event procedure which is code that must be written by the programmer. -- This click event procedure called btnCalculateGrossPay will cause the code below to be executed. When the button is CLICKED, this Event Procedure (code) is executed. Event Procedure

68. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Event Driven Programming: Events Slide 1- 68 Event Procedure triggered by a Click Event -- Pressing the Close button triggers a click event procedure which is code that must be written by the programmer. -- This click event procedure called btnClose will cause the code below to be executed. When the button is CLICKED, this Event Procedure (code) is executed. Event Procedure

69. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Procedural Programming Step by step instructions. Similar to a step-by-step recipe for baking a cake. Object-Oriented Programming The step-by-step instruction have already been written for us so that we can easily reuse the code. Examples: Buttons, Labels, Textboxes, etc… The code to produce these objects has already been written. Instructor: Create objects from the Toolbox Methods of Programming Slide 1- 69

70. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Procedural programming BUTTON – We would need to write hundreds of lines of code to create a Button on a Form. This is like writing a procedure for creating a chocolate cake. Object-Oriented programming BUTTON – In OOP the code is already written. All we need to do is use a copy of that code. Example: Double click on a Button in the Tool box and a Button is created on the Form. Methods of Programming Slide 1- 70

71. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Examples of Objects Slide 1- 71 Form Textboxes Labels Buttons Label The form is the larger rectangular object on which other objects are placed. Review on Objects

72. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Examples of Objects GUI: Graphical User Interface Objects consist of: Properties Properties on this form: Text Color Size Position Etc. Methods Calculate Gross Pay Close Min, Max Etc. Slide 1- 72 Review on Objects

73. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Examples of Objects Form elements are objects called controls This form has: Two TextBox controls Four Label controls Two Button controls The value displayed by a control is held in the text property of the control Left button text property is Calculate Gross Pay Buttons have methods attached to click events Slide 1- 73 Review on Objects

74. More About Controls and Programming Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 1.3 As a Visual Basic Programmer, You Must Design and Create the Two Major Components of an Application: the GUI Elements (Forms and Other Controls) and the Programming Statements That Respond to And/or Perform Actions (Event Procedures)

75. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley As a Windows user you’re already familiar with many Visual Basic controls: Label - displays text the user cannot change TextBox - allows the user to enter text - also allows the user to display text Button – performs an action when clicked RadioButton - A round button that is selected or deselected with a mouse click CheckBox – A box that is checked or unchecked with a mouse click Horizontal and Vertical Scroll Bars Form - A window that contains these controls Tutorial 1-3 demonstrates these controls Visual Basic Controls Slide 1- 75

76. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Tutorial 1-3, Visual Basic Controls Slide 1- 76 You must run this program and play with it. See Tutorial 1-3 in the book for directions.

77. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley All controls have properties Properties have a value (values) The Name Property allows the programmer to access a control from within a program. Name Property Slide 1- 77

78. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Examples of Names Slide 1- 78 btnCalcGrossPaybtnClose txtHoursWorked txtPayRate lblGrossPay Label1 Label2 Label3  The label controls use the default names (Label1, Textbox1, Button1, Form1, etc.)  Text boxes, buttons, and the Gross Pay label play an active role in the program and have been changed

79. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Control names must start with a letter Remaining characters may be letters, digits, or underscore 1st 3 lowercase letters indicate the type of control txt…for Text Boxes lbl…for Labels btn…for Buttons After that, capitalize the first letter of each word txtHoursWorked is clearer than txthoursworked NO spaces: txtHours Worked (Error) Naming Conventions Slide 1- 79

80. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Event Handler – Compute Gross Pay Slide 1- 80 Private Sub btnCalcGrossPay_Click(ByVal sender As System.Object, _ ByVal e As System.EventArgs) Handles btnCalcGrossPay.Click 'Define a variable to hold the gross pay. Dim decGrossPay As Decimal 'Convert the values in the text boxes to decimal numbers, 'and calculate the gross pay. decGrossPay = CDec(txtHoursWorked.Text) * CDec(txtPayRate.Text) 'Format the gross pay for currency display and 'assign it to the Text property of a label. lblGrossPay.Text = FormatCurrency(decGrossPay) End Sub

81. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Event Handler - Close Slide 1- 81 Private Sub btnClose_Click(ByVal sender As System.Object, _ ByVal e As System.EventArgs) Handles btnClose.Click 'End the program by closing its window. Me.Close() End Sub

82. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Keywords: Words with special meaning to Visual Basic (e.g., Private, Sub ) Programmer-defined-names: Names created by the programmer (e.g., decGrossPay, btnClose ) Operators: Special symbols to perform common operations (e.g., +, -, *, and /) Remarks: Comments inserted by the programmer – these are ignored when the program runs (e.g., any text preceded by a single quote) ‘This is a comment. Note the apostrophe (single quote). Language Elements Slide 1- 82

83. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Syntax defines the correct use of key words, operators, & programmer-defined names Similar to the syntax (rules) of English that defines correct use of nouns, verbs, etc. A program that violates the rules of syntax will not run until corrected Language Elements: Syntax Slide 1- 83

84. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley EXAMPLE OF AN "IN-CLASS LAB" Slide 1- 84 btnCalcGrossPay btnClose txtHoursWorked txtPayRate lblGrossPay Label1 Label2 Label3 Points 0 or 5 Be sure to fill out the AS15 Form as shown on the next slide and have it ready for instructor to collect. The form will not be collected if you have not completed the lab correctly. You will be given 30 minutes to complete the Lab. Steps: 1.This program must be done totally from memory. Immediate failure of the course will result if this rule is not followed. Remove all disks and flash drives from the system. 2.Create a GUI as seen below. 3.Use the object names as given below. 4.Code the program so that it produces the correct result. 5.Raise your hand as soon as you are finished so that instructor can grade you.

85. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley How to fill out the 15AS FORM ID FIELD - Use the RFID card ID number that is on your attendance card. Example: 12345 - TWO POINTS OFF IF NOT DONE CORRECTLY. Left justify your ID number as seen. Place the following answers on your Scantron: 1. a 2. a 3. a 4. a 5. a Last Name First Name Lab # Date Hour Slide 1- 85

86. The Programming Process Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 1.4 The Programming Process Consists of Several Steps, Which Include Design, Creation, Testing, and Debugging Activities Slide 1- 86

87. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Clearly define what the program is to do For example, the Wage Calculator program: Purpose: To calculate the user’s gross pay Input: Number of hours worked, hourly pay rate Process: Multiply number of hours worked by hourly pay rate (result is the user’s gross pay) Output: Display a message indicating the user’s gross pay Step 1 of Developing an Application Slide 1- 87

88. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Visualize the application running on the computer and design its user interface Step 2 of Developing an Application Slide 1- 88

89. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Make a list of the controls needed Step 3 of Developing an Application Slide 1- 89 TypeNameDescription TextBoxtxtHoursWorkedAllows the user to enter the number of hours worked. TextBoxtxtPayRateAllows the user to enter the hourly pay rate LabellblGrossPayDisplays the gross pay, after the btnCalcGrossPay button has been clicked ButtonbtnCalcGrossPayWhen clicked, multiplies the number of hours worked by the hourly pay rate ButtonbtnCloseWhen clicked, terminates the application Label(default)Description for Number of Hours Worked TextBox Label(default)Description for Hourly Pay Rate TextBox Label(default)Description for Gross Pay Earned Label Form(default)A form to hold these controls

90. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Define values for each control's relevant properties: Step 4 of Developing an Application Slide 1- 90 Control TypeControl NameText Form(Default)"Wage Calculator" Label(Default)"Number of Hours Worked" Label(Default)"Hourly Pay Rate" Label(Default)"Gross Pay Earned" LabellblGrossPay"$0.00" TextBoxtxtHoursWorked"" (Called a null string) TextBoxtxtPayRate"" (Called a null string) ButtonbtnCalcGrossPay"Calculate Gross Pay" ButtonbtnClose"Close"

91. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley List the methods needed for each control: Step 5 of Developing an Application Slide 1- 91 MethodDescription btnCalcGrossPay_ClickMultiplies hours worked by hourly pay rate These values are entered into the txtHoursWorked and txtPayRate TextBoxes Result is stored in lblGrossPay Text property btnClose_ClickTerminates the application

92. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Create pseudocode or a flowchart of each method: Pseudocode is an English-like description in programming language terms A flowchart is a diagram that uses boxes and other symbols to represent each step Step 6 of Developing an Application Slide 1- 92 TWO EXAMPLES OF PSEUDOCODE: Store Hours Worked x Hourly Pay Rate in decGrossPay. Store the value of decGrossPay in lblGrossPay.Text. Start End Multiply hours worked by hourly payrate. Store result in decGrossPay. Copy value in decGrossPay to lblGrossPay text property

93. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Check the code for errors: Closely examine flowchart and/or pseudocode Step through each operation as though you are the computer. Play being the computer. Use a piece of paper to jot down the values of variables and properties as they change. Verify that the expected results are achieved Step 7 of Developing an Application Slide 1- 93

94. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Use Visual Basic to create the forms and other controls identified in step 3 This is the first use of Visual Basic, all of the previous steps have just been on paper Develop what the user will see on the form. Step 8 of Developing an Application Slide 1- 94

95. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Use Visual Basic to write the code for the event procedures and other methods created in step 6 This is the second step on the computer In this step you develop the methods behind the click event for each button Unlike the form developed on step 8, this portion of the application is invisible to the user Step 9 of Developing an Application Slide 1- 95

96. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Attempt to run the application - find syntax errors Correct any syntax errors found Syntax errors are the incorrect use of an element of the programming language Repeat this step as many times as needed All syntax errors must be removed before Visual Basic will create a program that actually runs Step 10 of Developing an Application Slide 1- 96

97. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Run the application using test data as input Run the program with a variety of test data Check the results to be sure that they are correct Incorrect results are referred to as a runtime error Correct any runtime errors found Repeat this step as many times as necessary Step 11 of Developing an Application Slide 1- 97

98. Visual Studio and the Visual Basic Environment Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley 1.5 Visual Studio Consists of Tools That You Use to Build Visual Basic Applications Slide 1- 98

99. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Visual Studio is an integrated development environment, often abbreviated as IDE Provides everything needed to create, test, and debug software including: The VB language Form design tools to create the user interface Debugging tools to help find and correct programming errors Visual Studio supports other languages beside Visual Basic such as C++ and C# The Visual Studio IDE Slide 1- 99

100. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Tutorial 1-4 introduces elements of the IDE: Customizing the IDE Design window – a place to design and create a form Solution Explorer window – shows all the files in the solution Properties window – modify properties of an object Dynamic Help window – a handy reference tool Toolbar – contains icons for frequently used functions Toolbox window – Classes used in form design Tooltips – a short description of button’s purpose The Visual Basic Environment Slide 1- 100 THE END

101. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley THREE TYPE OF ERRORS IN PROGRAMMING Slide 1- 101 1. Syntax errors 2. Runtime errors 3. Logic errors Generally speaking, the errors become more difficult to find and fix as you move down the above list. Syntax errors --In effect, syntax errors represent grammar errors in the use of the programming language. Common examples are: --Misspelled variable and function names --Missing semicolons --Improperly matches parentheses, square brackets, and curly braces --Incorrect format in selection and loop statements

102. Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley THREE TYPE OF ERRORS IN PROGRAMMING Slide 1- 102 Runtime errors Runtime errors occur when a program with no syntax errors asks the computer to do something that the computer is unable to reliably do. Common examples are: --Trying to divide by a variable that contains a value of zero --Trying to open a file that doesn't exist --There is no way for the compiler to know about these kinds of errors when the program is compiled. Logic errors Logic errors occur when there is a design flaw in your program. Common examples are: --Multiplying when you should be dividing --Adding when you should be subtracting --Opening and using data from the wrong file --Displaying the wrong message