Download ISYS 573 Special Topic – VB.Net

ISYS 573
Special Topic – VB.Net
David Chao
The History of VB
• Early 1960s:BASIC-Beginner’s All-Purpose
Symbolic Instruction Code
– Teaching
– Simple syntax, easy-to-use
– Interpreted language – slow
• Microsoft’s long history of commitment to BASIC
– In the 1980s: QuickBasic, QBasic (shipped with DOS)
– In the early 1990s, VB 1.0
• Visual interface design and creation
• Even-driven programming
• Easy database access
– 2002: VB .Net
• Challenges: Java, Internet application development
Portability
Java: Write Once Run Anywhere
Java Byte Code
Java Source Code
Java Virtual Machine
(JVM)
Java Byte Code
(Intermediate Code)
Executable Code
Microsoft’s .Net
• Language must compliance with Common
Language Specification, CLS.
• Compile the language into Microsoft Intermediate
Language (MSIL) code.
• The MSIL code is then executed in the
Common Language Runtime (CLR), which
conceptually is same as the JVM, where it is
translated into machine code by a compiler.
.Net Architecture
VB.Net
C#
C++
Common Language Specification
ASP.Net
Windows Forms
Data and XML
Base Class Library
Common Language Runtime
• Common Language Runtime:
– Manages execution of compiled .NET program.
– Provides .Net basic services, such as memory
management, garbage collection, etc.
• Base Class library: define all the basic data types
such as system.object, numeric, date, etc.
• Data and XML: Classes work with database
(ADO.NET) and XML document.
• ASP.Net and Forms: Classes that generate user
interface.
• CLS: CLS dictates the minimum group of features
that a .Net language must have.
.Net Advantages
• It is independence from a specific language.
Developers can create a .Net application in any
.Net compatible language.
– .Net moves most of the functionality from the language
to the .Net Framework. All .Net language can use these
classes.
• It can exist on multiple platforms, further
extending the portability of .Net programs.
• Facilitate internet application development:
– ASP.Net: Web Forms and XML Web services.
• Universal data access: Data can be accessed by
any Internet-connected device.
Programming in the .Net
Framework
• Programming in the .Net Framework means
making use of the classes, objects, and
members exposed by the Framework,
building your own classes on top of these
and manipulating the resulting objects using
a .Net language.
• Ex. VB form is derived from
System.Windows.Forms.Form class.
Partitioned Application and
Component
• An application designed to run on a distributed system is
referred to as a partitioned application.
• A partition application consists of several parts, and each
part perform a specific and well-defined task.
• Each part of the partitioned application is referred to as a
component
• A component interacts with others via interface: properties,
methods, and events supported by the component
Interoperability Between Components
• To provide object integration and allow
functional components that provide
specific services to be created and
plugged from one application to
another.
Benefits of Building Applications from
Components
• Reusability
– Many applications can share the services provided by the
same component.
• Manageability
– By dividing a program into components, a project can be
divided into smaller, more manageable tasks, and each
individual programmers can build components for which
their skills are best suited.
• Maintenance
– Each component can be maintained as an individual unit.
• Flexibility
– Components are not bound to a physical location, and can
be redistributed to other physical location.
XML and .NET
• .NET Framework uses XML for:
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–
–
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Configuration
Cache dataset
Web services
Web form layouts
Etc.
• XML data combined with schema are
becoming increasingly important.
XML Example
<?xml version="1.0" ?>
<Books>
<Book>
<ISBN>1-34567-04-01</ISBN>
<Authors>
<AuthorName>John Smith</AuthorName>
<AuthorName>Peter Chen</AuthorName>
<AuthorName>David Chao</AuthorName>
</Authors>
<Price> $45.00</Price>
<Description>This is a great book</Description>
</Book>
<Book>
<ISBN>1-34567-04-02</ISBN>
<Authors>Adam Smith</Authors>
<Price> $25.00</Price>
<Description>This is a second great book</Description>
</Book>
</Books>
Major Topics in ISYS 573
• VB.Net language
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Event-driven programming
Component programming
Object-oriented programming
Database access
• .Net Framework classes
• Internet applications
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Web forms
Web services
Web controls
XML