'NET

1
.NET

• Johan Muskens
• Technische Universiteit Eindhoven

2
Agenda

• Topics
• Introduction to .NET

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What is the .NET Framework?

• Selling speech
• The .NET Framework is the new library of classes
  that you use to build Windows applications.
• The .NET Framework is a computing platform that
  has been designed to simplify the development of
  applications, such as
• Applications that use sophisticated GUI front
  ends
• Applications that use Internet
• Applications that are distributed over more than
  one computer
• Applications that make sophisticated use of
  databases

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What does .NET give you?

• The .NET Framework provides the following to a
  developer
• Language independence
• Standard building blocks (for GUI, Database,
  etc)
• A way to create your own building blocks
  (assemblies)
• Distribution of components
• OS independence ???

5
Intermediate Language
C code
VB code

• All .Net languages compile down into an
  intermediate form called Intermediate Language
  (IL).
• IL is similar to Java byte code
• Can not directly executed on target system
• Portable
• Always converted into native code (unlike
• Java) by JIT compiler.
• More than just low-level machine independent
• object code.

C compiler
VB compiler
IL code
IL code
IL provides cross language interoperability when
you make some agreements
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Common Type System
AGREEMENT PART I

• The Common Type System provides a specification
  for how types are
• Defined
• Managed
• Used
• This is important for cross-language integration!
• The CTS provides rules that languages must obey,
  to ensure that types created in different
  languages can interoperate with one another.

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Common Language Specification
AGREEMENT PART II
The Common Language Specification is a set of
rules and constraints that compiler and library
writers need to follow to be sure that the
languages and code they produce will interoperate
with other .NET languages. The Common Language
Specification is a subset of the Common Type
System.
If language complies to CLS it can
interoperate with other .NET languages
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2 Main Components

• There are two main components to the .NET
  Framework
• Common Language Runtime Language independence
• The CLR is responsible for execution of IL-code
  within the .NET environment, providing services
  such as security, memory management and remoting.
  (managed and unmanaged code)
• .NET Framework Class Library Standard building
  blocks
• The .NET Framework Class Library is an library of
  classes that provides all the tools you need to
  write a wide variety of programs.

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Metadata

• .NET assemblies are self-describing, in that they
  carry descriptive information with them. This
  information, called metadata, includes the
  following information
• Name, version, and culture-specific information
  for the assembly
• The types that are exported by the assembly
• Dependencies on other assemblies
• Security permissions needed to run
• Information for each type in the assembly (name,
  visibility, etc)
• Additional attribute information
• Most of the metadata is created by the compiler
  when it produces IL.

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Assemblies

• Assemblies are the basic building blocks from
  which .NET applications are constructed, and are
  the fundamental unit of deployment and
  versioning. Assemblies are deployed as DLLs or
  Executables.
• An assembly contains
• IL code
• Metadata describing assembly and its contents
• Files needed for run-time operation

IL Code
DLL or Executable
Meta data
RT operation
RT operation
RT operation
Self contained
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.NET Framework Namespaces

• The classes in the .NET Framework Class Library
  are structured using namespaces.
• A name space groups classes that implement
  related functionality
• Namespaces make sure the Framework Class Library
  doesnt get an
• unorganized container of classes.

the next slides will present some example
namespaces
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IO Namespace

• The IO namespace provides the classes that
  implement the .NET I/O functionality.
• Example classes
• BinaryReader
• BinaryWriter
• Stream
• StreamReader
• StreamWriter
• IOException

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Forms Namespace

• The Forms namespace provides the classes used for
  programming with forms. This namespace is huge
  (over 300 classes)
• Example classes
• Application
• Button
• ComboBox
• Panel
• FileDialog
• Form

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NET Namespace

• The NET namespace provides the classes
  implementing network support
• Examples
• talking to HTTP servers
• talking to FTP servers
• DNS lookup
• manipulating IP addresses
• managing cookies
• authentication

ftp
http
dns
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XML Namespace

• The XML namespace provides the classes
  implementing creating, manipulation, etc of XML.
• Examples classes
• Xml (processing xml)
• Schema
• Serialization
• XPath
• XSL

lt?xml version"1.0" standalone"no"?gt ltMailgt
ltFromgtAuthorlt/Fromgt ltTogtReceiverlt/Togt ltDategt Thu,
7 Oct 1999 111516 -0600lt/Dategt ltSubjectgtXML
Introductionlt/Subjectgt ltbodygtltpgtThanks for
readingltBr/gt this articlelt/pgt ltbr/gt ltpgtHope you
enjoyed this articlelt/pgt lt/bodygt lt/Mailgt
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Web Namespaces

• The Web namespace provides the classes related to
  Web programming.
• Examples classes
• Web
• HttpResponse
• Mail
• UI (Server side controls)
• Services

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Web Services Distribution

• Web Services let client code access software
  components across networks using standard
  protocols such as SMTP and HTTP.
• Infrastructure needed to make Web Services work
• Data formats and protocols to enable Web
  Services to communicate
• A standard way for Web Services to describe
  themselves
• A way for clients to discover Web Services

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Data Formats and Protocols

• One of the advantages of Web Services over COM
  and CORBA is the use of standard data formats and
  protocols over proprietary offerings.
• Clients can communicate with Web Services in
  three ways
• Using HTTP GET commands
• Using HTTP POST commands
• Using SOAP (Simple Object Access Protocol)

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Web Service Description

• The .NET Framework provides a Web Service
  Description Language (WSDL). It describes
• Methods exposed
• Input parameters
• Output parameters

It provides this information using XML
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Web Service Discovery

• DISCO (Discovery of Web Services)
• SOAP based protocol
• Defines format for description of data
• Protocol for retrieving this data
• Advertisement of Web Services Posting DISCO
  files on your Server
• Clients use DISCO files to navigate to
• WSDL documents

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COM Enterprise Java Beans - .NET

• Deploy the class as a Dynamic Link Library or
  Executable
• Deploy bean as a JAR file
• Deploy assembly as a Dynamic Link Library or
  Executable
• Notion of interfaces and implementations
• Notion of interfaces (Remote Interface Home
  Interface) and implementation (bean)
• Notion of exposed methods (Described in Web
  Service Description Language)
• Use abstract base class to define binary
  interfaces
• Enterprise Java Bean Server / Container
  specification
• Use intermediate language, common type system,
  common language specification

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COM Enterprise Java Beans - .NET

• Techniques for dynamically selecting
  implementations
• Use Java Naming and Directory Interface for
  locating Beans (actually home object)
• DISCO (Discovery of Web Services) protocol
• Dynamic discovery of implemented interfaces
• ??? Not applicable because you never talk to
  bean directly.
• ??? Use Web Service Description Language

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References
Microsoft Visual C .NET Step by Step
(2002) Julian Templeman and Andy Olsen ISBN
0-7356-1567-5
Web Services Essentials (2002) Ethan
Cerami ISBN 0-596-00224-6