1. CSCI 3327 Visual Basic Chapter 1: Introduction to Visual Basic
UTPA – Fall 2011
This set of slides is revised from lecture slides of Prof. John Abraham. -- Xiang Lian

2. Demo

3. Objectives In this chapter, you will
Recall basic components in a computer system
Learn the evolution of programming language
Learn the history of Visual Basic
Find the differences between structural programing and object-oriented programing
Become aware of the .NET Framework for Visual Basic

4. CSCI 1380: Elements of a Computer System
Hardware
CPU
Main memory
Secondary storage
Input / Output devices
Software
System programs
Application programs (e.g. Visual Basic)

5. Programming Languages
Machine language
Assembly language
High-level language

6. History of Visual Basic
BASIC (Beginner's All-purpose Symbolic Instruction Code)
1960, Profs Kemeny and Kurtz
1970s, Bill Gates implemented BASIC on several early PCs
Late 1980s ~ early 1990s, Microsoft developed Microsoft Windows graphical user interface (GUI)
Basic  Visual Basic
Visual Basic is created in Integrated Development Environment (IDE)

7. Milestones
Structured Programming  Disciplined approach to creating clear, correct and easy to modify programs. Pascal 1971
Procedural Programming
Object Technology  Packaging Scheme for creating meaningful software units

8. Object Technology
We humans are very good in recognizing and working with objects, such as a pen, a dog, or a human being.
We learned to categorize them in such a way that make sense to us. We may categorize them as animate object, inanimate objects, pets, friends, etc.

9. Object Technology (cont'd)
We some times classify objects based on their attributes, for example, green apples or red apples, fat or slim people, etc.
If you think about it each object has many attributes. If I ask you list the attributes of an orange, you probably could list many things such as color, shape, weight, smell, etc.

10. Object Technology (cont'd)
In addition to attributes, all objects exhibit behaviors.
A dog eats, barks, wags its tail, plays, and begs. A dog exhibits many more other behaviors than this short list.
Another thing we need to remember about objects is that objects interact between each other.

11. Object Technology in Visual Basic
Object-oriented
E.g. forms, labels, buttons, radios, checkboxes, etc.
Properties of objects
E.g. background color of forms
Event-driven
Behaviors  events of objects
E.g. clicks

12. XML (eXtensible Markup Language)
HTML has fixed tags which is a limitation
XML is definable
Separation of data from description of data (data independence)
XML can be used by any software or language

13. ARTICLE.XML file <?xml version = "1.0"?>
<!-- Article structured with XML -->
<article>
<title>Simple XML</title>
<date>December 6, 2001</date>
<author>
<firstName>John</firstName>
<lastName>Doe</lastName>
</author>
<summary>XML is pretty easy.</summary>
<content>In this chapter, we present a wide variety of examples that use XML.
</content>
</article>

14. What is .NET? .NET is an Internet and Web based infrastructure
.NET delivers software as Web Services – XML based.
.NET will run in any browser on any platform
.NET framework is the infrastructure for the new Microsoft .NET Platform.

15. What are Web Services?
Applications that run on a web server and communicate with other applications
The basic platform of Web services is XML + HTTP

16. What is .NET built on? Windows Servers: SQL Application Center
Commerce Server
Mobile Information Server
Exchange Server
BizTalk Server
Internet Security
Host Integration

17. .NET Framework A software platform Language-neutral
Designed for cross-language compatibility
Applications written in VB may reference a DLL file written in any other language
2 components:
Common Language Runtime (CLR)
Class Libraries

18. Common Language Runtime
Execution Engine of .NET
Manages the execution of programs and provides core services:
Code compilation
Memory allocation
Thread management
Garbage collection

19. Common Language Runtime (cont'd)
Output of .Net compilation contains a special type of code called Microsoft Intermediate Language (MSIL); it is not executable
MSIL is independent of any specific CPU.
CLR translates MSIL to executable code when the program is executed
Executable code is produced using JIT (just-in-time) compiler. The native code produced by JIT is specific for the CPU.

20. Class Libraries Designed to integrate with the common language runtime
This library gives the program access to runtime environment
The class library consists of lots of prewritten code that all the applications created in VB .NET and Visual Studio .NET will use
The code in Visual Basic for all the elements like forms, and controls actually comes from the class library

21. Reasons Why Developers Build Applications Using the .NET Framework
Improved Reliability
Increased Performance
Developer Productivity
Powerful Security
Integration with Existing Systems
Ease of Deployment
Mobility Support
XML Service Support
Support for over 20 Programming Languages
Flexible Data Access

22. Visual Basic (VB) Forms designer In-place menu editor
Automatic control anchoring and docking
Integrated Development Environment (IDE)
Create Web applications using the shared Web forms designer
Full object-oriented constructs - inheritance, encapsulation, and polymorphism

23. Concepts of Object-Oriented Programming
Objects
Classes
Data Abstraction and Encapsulation
Inheritance
Polymorphism

24. VB Object-Oriented Approach
Emphasis on data rather than procedure
Programs are divided into Objects
Data is hidden and cannot be accessed by external functions
Objects can communicate with each other through functions
E.g. click event of a button
New data and functions can be easily added whenever necessary
Follows bottom-up approach