1. IS 118 Introduction to Development Tools
VB Chapter 01-02
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2. Things to Cover What is Visual Basic – (VB) Chapter 2
How it operates vs. Others
Sound Program Criteria
Chapter 2
The IDE
Forms, and Controls
Events, properties and methods
Coding and Naming conventions
Running Executables
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3. Note
For These chapters we will follow the book and you should follow along on your computer as we do it
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4. Evolution of Visual Basic
Evolved from BASIC (Beginner’s All-Purpose Symbolic Instruction Code)
Designed to provide interactive computing on mainframe computers
Widely available on early microcomputers
Introduction of personal computers (early 1980’s)
Microsoft introduced GW-Basic with the DOS operating system
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5. Language Processors
Required to process programs into a program the computer can understand
Interpreters
Read, interpret, and carry out one line of code at a time
Compilers
Translate a source program (i.e. one written in VB)
Create an object program (one a machine can read)
Object programs also called “executables”
Compiled programs run much faster
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6. Characteristics of Visual Basic
Provides visual objects (controls) that can be drawn onto a window (form)
Makes building the interface much easier
Object-oriented code structure
Code structured around objects
Easy to understand syntax
“IntelliSense” technology helps write code
Objects can be reused and extended through inheritance
Event-driven language
Things happen in response to events
Examples of events: mouse click, opening or closing a window
The user, not the program determines the sequence of operations
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7. Creating a VB Program
Takes place in the Visual Studio Integrated Development Environment (IDE)
Provides an environment for creating the interfaces, writing and testing code, and making changes
Provides the .NET framework for Web services, Visual C#.NET, Visual Basic.NET, etc.
Statement: an instruction that can stand alone
Code: a group of statements
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8. Overview of VB Program Development
Criteria of a sound application
Internal criteria geared to the programmer
External criteria geared to the user
Program development cycle
Understand distinct steps in the process of developing an application
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9. External Criteria Functionality Efficiency User-Friendliness
Does the program do what it is supposed to do?
Efficiency
Program should minimize the use of computer resources
Includes memory, processing time, and storage space
User-Friendliness
Make the application easy to use
Includes helpful error messages, guarding against user errors, consistent appearance and behavior of windows
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10. Internal Criteria Consistency in coding style
Following conventions most programmers follow
Indenting blocks of code
Naming objects with predefined prefixes
Code clarity and readability
Use meaningful variable names
Adding comments to code can aid understanding
Modularity in code design
Each block of code is isolated from the rest of the program
Easier to debug, review, and revise
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11. Internal Criteria Elegant algorithms Code maintainability
Algorithm: a systematic approach to solving the programming problem
Logic easy to trace and implement
Efficient in terms of speed and storage requirements
Code maintainability
General applicability: code will not require revision even if the program requirements change
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12. Steps in Developing a Program
Developing an application requires several distinct steps
Skipping or not giving careful attention to steps can create a lot of rework, headaches, and expense
Mistakes made in the earlier stages of program development require much more time, money, and hassle to rework
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13. Steps in Program Development
Analyze and define the problem
Program must meet application needs
Design the visual interface
Decide what data fields appear and the appropriate controls
Define User-Program Interaction
Define events, both user actions and system activities
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14. Steps in Program Development
Design the code structure
Structure dictated by responses program should carry out
Well-designed code enhances maintainability
Write Code
Develop code based on your analysis of the problem and design of the structure
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15. Steps in Program Development
Test and edit the program
Various error types:
Syntax errors: failure to follow programming rules
Semantic errors: failure to say what you mean
Logic errors: difference between what programmer thinks code will do and what it actually does
Place the program into production
Production program works with live data and produces “real” results
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16. Learning the Language
Comparing learning a spoken language and learning a programming language
Vocabulary
Types of objects, methods, and events
Grammar
Syntax rules
Semantics
Meaning of how programming constructs fit together
Effectiveness
Finding better ways to express the same idea
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17. Hands-on Practice
Programming is a skill, like playing a sport or a musical instrument
Practice enables you to gain familiarity with:
The IDE
The vocabulary and syntax rules of VB
How different parts of the code fit together
Identify opportunities for code improvement
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18. The IDE –lets do it
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19. Summary Visual Basic evolved from BASIC
Visual elements allow easy changes in user interface
Object-oriented syntax makes it easier to learn vocabulary and syntax
Object-oriented language enhances code reusability
Inheritance allows programmer to reuse code
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20. Summary
Sound programs must meet internal criteria and external criteria
There are distinct steps in developing code. Don’t try to shortcut the early stages
Learning a programming language is like learning a spoken language
PRACTICE, PRACTICE, PRACTICE
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21. Chapter 2 Introduction to Visual Basic Programming
Visual Basic.NET
Copyright (c) 2003 by Prentice Hall

22. Objectives Navigate the IDE
Create controls on a form and adjust their sizes
Understand the events, properties, and methods of controls
Understand how the code and events work in a VB program
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23. Objectives Open and save a VB project
Understand the coding mechanics and the naming convention
Get help from the MSDN help system
Enumerate the types of statements in a program
Run an executable without the IDE
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24. The IDE Profile
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25. Starting the IDE
The Visual Studio Start Page
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26. Starting a New Project
Default: Windows Application
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27. The Integrated Development Environment (IDE)
Menu bar provides many menu items
Examples include File and Edit menus
Toolbar lies below menu bar
Provides shortcuts to the menu bar
Toolbox
Contains various icons representing VB controls
Solution Explorer
Shows all forms, references, classes, and modules the current project contains
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28. The IDE
Menu bar
Toolbar
Toolbox
Blank form in IDE
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29. Solution Explorer and Properties Window
Solutions Explorer shows all the forms, references, classes, and modules in the project
Properties window shows all the properties of the selected object
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30. Your First Visual Basic Program
Form contains a label and a button
Double-click the button on the form to open the code window
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31. The Code Window
Tabs at top let you toggle between the form and the code window
Procedure box lists events the object in the object box recognizes
Object box lists all objects in the form
Comments appear green in the IDE
Object-oriented syntax: object and property separated by dot (period)
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32. When You Run the Program
Label changes when you click the Say Welcome button
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33. Understanding the IDE Design time Runtime
When you are placing controls on the form
When you are writing code in the code window
Runtime
When the code in your project comes to life, responding to events
Press Start on the Debug menu in the IDE
Press the F5 key in the IDE
Press the start button in the IDE
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34. Coding Mechanics Comments Showing Blocks of Code Line Continuation
Used to provide clues to the purpose of the code
Begin with tick mark (apostrophe) or Rem
Appear green in the IDE
Showing Blocks of Code
The IDE will help indent the code lines
Line Continuation
If you have to write a long statement, break into lines by using the underscore (_) character
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35. Interfaces of VB Objects
Forms and controls are objects
Objects have interfaces:
Properties: typically relate to appearance of objects
Events: user or system actions recognized by the object
Procedures written to handle events
Methods: actions that objects are capable of performing
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36. Properties Special types of data associated with object
Most relate to appearance of objects
i.e. Label1.BackColor = Color.Red
Some relate to behavior of objects
i.e. btnNext.Enabled – True
Object and property separated by dot (period)
Property must be given a value
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37. Events User or system actions the object recognizes Event procedure
i.e. a button has a Click event
Event procedure
Procedure written to handle a specific event
Also called event handler
Syntax: Private Sub ObjectName_Event
Code surrounded by Sub … End Sub
Private refers to the scope of the procedure
Object and event separated by underscore
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38. Methods Actions objects are capable of performing
i.e. Me.Close()
Syntax: Object.Method(Parameter List)
Parameter list: arguments passed in to the method
Parameter list must be enclosed in parentheses, even if no parameters are required
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39. Getting Help from the Help Menu
Enter search term in the Look for box
Double-click an item in the list box
Double-click an item in the lower center pane; upper center pane shows results
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40. Naming objects When naming objects, be descriptive
Use standard prefixes, i.e. lbl for label
Give the object a meaningful name
i.e. a label with text “Name” could be lblName
Change the object name in the Properties window
Name objects before placing code in the code window
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41. Assignment Statements
Generate some sort of result
i.e. moving data from one location in memory to another
Syntax: lblWelcome.Text = “Welcome”
Expression on right hand side of equation moved to memory location on left hand side
Most common statements in VB programs
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42. Statements That Direct Execution Flow
Conditional Execution
One block of code executed if a statement is true; a different block executed if false
If block is most common example
Repetition
When you need to execute a block of code repetitively
For…Next loop is most common
Code that “Jumps”
Exit Sub exits a procedure
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43. Completing the Development Cycle
Program must be compiled into executable
When you test run your program, the IDE compiles and saves the executable
To run the program:
Double-click the executable
Use the Run option off the Start menu
Add the executable to your Start menu
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44. Finding the Executable
Executable is found in the /bin folder underneath the folder containing your project.
In this case: C:\My Documents\ Visual Studio Projects\Welcome
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45. Summary Start the IDE from the Start Menu
Choose Visual Studio.NET from Programs menu
Edit your profile to customize environment
Menu bar gives you all menu items. Toolbar offers shortcuts to menu items
Toolbox contains controls and components
The form allows you to design visual elements
Code window behind form is where you place code
Solution Explorer shows all files in your solution
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46. Summary Properties window shows properties of selected object
To develop a program
Draw and adjust the controls on the form
Set properties of the objects
Place code in events, then test and revise
The IDE allows you to write and compile the program
Use comments in your code to show the purpose of the code
Break long code lines with an underscore character
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47. Summary
Objects have three types of interfaces: properties, methods, and events
VS.Net help file provides a wealth of information
Follow object naming conventions
Use predefined prefixes for objects
Give objects meaningful names
Two types of programming statements:
Those that produce results
Those that control program flow
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48. Summary Four types of objects introduced:
Form used for visual interface
Label used to display text to give clues
Button used to trigger actions
Timer used to keep track of time
IDE automatically produces the executable when you develop the program
Run the executable like other Windows programs
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