Machine & High Level Languages Machine Assembly High See page 8 for a comparison BASIC 1960 Profs Kemeny and Kurtz
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.
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
SOAP Simple Object Access Protocol. SOAP is a communication protocol, for communication between applications (transmission of objects over the Internet). SOAP is a format for sending messages SOAP is designed to communicate via Internet SOAP is platform independent SOAP is language independent SOAP is based on XML SOAP is simple and extensible SOAP allows you to get around firewalls SOAP will be developed as a W3C standard
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.
What are Web Services? Applications that run on a web server and communicate with other applications. The basic Web services platform is XML + HTTP Web services platform elements –SOAP (Simple Object Access Protocol) –UDDI (Universal Description, Discovery and Integration) –WSDL (Web Services Description Language)
UDDI Like the yellow pages of Web services Universal Description, Discovery and Integration UDDI is a directory for storing information about web services UDDI is a directory of web service interfaces described by WSDL UDDI communicates via SOAP UDDI is built into the Microsoft.NET platform
WSDL Web Services Description Language WSDL is written in XML WSDL is an XML document WSDL is used to describe Web services WSDL is also used to locate Web services
What is.Net built on? Windows Servers such as: SQL Application Center Commerce Server Mobile Information Server Exchange Server BizTalk Server Internet Security Host Integration
.Net Framework A software platform Language-neutral Designed for cross-language compatibility. App written in VB.net may reference a DLL file written in any other language 2 components: Common Language Runtime (CLR) Class Libraries
Common Language Runtime Execution Engine of.NET Manages the execution of programs and provides core services: Code compilation Memory allocation Thread management Garbage collection Common Type System (CTS) enforces safety.
CLR contd. 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.
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 for all the elements like forms, and controls actually comes from the class library.
Some reasons why developers are building 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
Visual Basic.NET Visual Basic.NET 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
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 New data and functions can be easily added whenever necessary Follows bottom-up approach
OOP concepts Objects Classes Data Abstraction and Encapsulation Inheritance Polymorphism
Classes and Objects Classes are types and Objects are instances of the Class (like variable types and variables) The Syntax for a Class –Public Class Test ----- Variables -----Methods -----Properties -----Events End Class
Creating an object for class Test use the new keyword: – Dim obj as new Test(). –Open a Console Application and place the code shown in next slide
Module Module1 Imports System.Console Sub Main() Dim obj As New Test() 'creating a object obj for Test class obj.disp() 'calling the disp method using obj Read() End Sub End Module Public Class Test 'creating a class named Test Sub disp() 'a method named disp in the class Write("Welcome to OOP") End Sub End Class