Unit -1
Chapter -1
REVIEW OF .NET FRAME WORK
Topics to be covered
1.
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2.
3.
4.
5.
6.
Introduction to .NET framework
the Microsoft .NET strategy.
Why is .NET?
.NET product.
.NET services.
The origin of .NET technology.
Brief history of .NET.
The .NET framework application.
The core feature of .NET framework.
Benefits of the .NET approach:
.NET framework 4.0 architecture(introduction and feature).
Feature of .NET framework and asp.net 4.0
6. Execution environment of .NET framework application.
(1). Common language runtime(CLR).
 Source code
 Compiler.
 Metadata.
 Microsoft Intermediate language(MSIL).
 Managed code.
 Class loader.
 Base class library or.net framework class library.
 Just in time compiler(JIT).
 Native machine code.
 Runtime manager.
 NET Assembly
a. Kinds of assemblies-private and shared.
b. Component of assemblies- manifest, module, type
c. Function of assemblies.
(2). Common language specification(CLS).
(3). Common type system(CTS).
(4). Garbage collector(GC).
(5). How the garbage collector works.
(6). Namespace
The Microsoft .NET strategy.
• Microsoft wanted to make the www more vibrant
by enabling individual devices, computers and
web services to work together intelligently to
provide richer solution to the users.
• By the intelligent ,integration of website on the
internet, user can create a wide variety of value
based applications such as unified banking
services, electronic bill payment etc.
• Microsoft calls this “web services” and the
software strategy for implementing and
delivering those services as “.NET”
Contd….
• .NET is a software framework that includes
everything required for developing software
for web services. It integrates presentation
technologies,componet technologies and data
technologies on a single platform so as to
enable users to develop internet application
as easily as they do desktop system.
Why .NET?
• The world of computing till date has been
chaotic. We have had various languages
struggling to interoperate with each other,
developers undergoing huge learning curves to
shift from one language to another or from one
application type to another, non-standard ways of
modeling applications and designing solutions
and huge syntactic differences between
languages. The list goes on....
• Basically,microsoft introduce the .NET framework
with the intention of bridging the gap in
interoperability between application.
Contd….
• This framework aim at integrating various
programming languages and services.
• It is designed to make significant improvement
in code reuse, code specification, resource
management,multilanguage development,
security deployment and administration.
• It consist of all the technologies that help in
creating and running robust scalable and
distributed applications.
• The .NET offers a complete suite for
developing and deploying applications.
Contd….
The Microsoft .NET software solution strategy(suit)
includes three key approaches:
MS.NET STRATEGY
MS .NET PLATFORM
MS.NET PRODUCT
AND SERVICES
THIRD PARTY .NET
SERVICES
•
Contd….
• MS .NET platform includes the following
component that would help developing a new
generation of smart internet services, and they
are:.NET infrastructure and tools .NET framework.
 .NET user experience console application, windows
application, libraries etc.
 .NET building blocks CLR,CTS,base class etc.
 .NET device software embedded system.
•
contd..
• Microsoft .NET product and services consist
of the following:Windows .NET.
MSN .NET.
Office .NET.
Visual studio .NET.
Personal subscription services.
bCentral for .NET.
Contd…
• Third-party .NET services:
Third-party .NET services will provide opportunities to
vast range of developers and users to produce
corporate and vertical services using .NET platform.
• The third-party languages are: COBAL
 Smalltalk
 Mercury
 Perl
 Python
• Native languages are: VB
 C++
 C#
Brief history of .NET
• The Microsoft .Net is a new internet technology
or rather strategy introduced by Microsoft. .Net
was originally known as the NGWS (Next
Generation Windows Services) which was said to
be an Internet based platform of Next Generation
Windows Services. Before the official
announcement of .Net, NGWS was the term used
to describe the above phrase.
• The .NET Framework was first released in in
November 2000 and development continues
today. Each version of the framework has betas,
final versions, service packs, and patches
associated with it.
Version
Version Number
Release Date
1.0
1.0.3705.0
02/13/2002
1.1
1.1.4322.573
04/24/2003
2.0
2.0.50727.42
11/07/2005
Visual Studio
Default in
Windows
VisualStudio.NET
Visual Studio
.NET 2003
Visual Studio
2005
3.0
3.0.4506.30
11/06/2006
3.5
3.5.21022.8
11/19/2007
Visual Studio
2008
4.0
4.0.30319.1
04/12/2010
Visual Studio
2010
Windows Server
2003
Windows Vista,
Windows Server
2008
Windows 7,
Windows Server
2008 R2
The origin of .NET technology
Note: Before going into the detail of .NET feature further, we shall see how
the concept of .NET was evolved over the past 10 years by Microsoft corp.
• The current technology of .NET has gone through three
significant phases of development. and they are:Interprocess
communication
Intermodule
communication
Intersite
communication
OLE TECHNOLOGY
COM TECHNOLOGY
.NET TECHNOLOGY
Object linking and
embedding
(early phase-I 1990s)
Component object
module or model
(phase-II 1995)
Phase-III 1990’s
later years
• Contd…
• Interprocess communication more than one
independent process communicate with each
other. Ex: crystal report with VB or VB.NET.
• Intermodule communication integration of
independent component or module developed in
a particular language with each one is offering a
particular service: VB 6.0 module ,java classes or
packages etc.
• Intersite communication cross language
compatibility i.e. module developed in any
language included in .NET package can be merged
together to create an application.
.NET Technology
• .NET technology is a third generation component
model.
• This provides a new level of interoperability
compare to COM technology.
• COM provides a standard binary mechanism for
intermodal communication. This mechanism is
replaced by an intermediate language called
Microsoft Language (MSIL) or simple IL in the
.NET technology.
• Various .NET language compiler enforce interoperability by compiling code into ILs which is
automatically compatible with other IL modules.
• An inherent characteristics of IL code is
metadata.
Monolithic approach vs .NET platform
compile
Source code
Object code
linking
execution
.NET TECHNOLOGY
csc
Source code
Manage
code
IL
CLR
(loading,
running and
checking
Exe/dll
code
JIT
Native
code
The .NET framework
• The .NET framework is one of the tools provided by the
.NET infrastructure and tool component of .NET
platform.
• .NET platform provides a new environment for
creating and running robust, scalable and distributed
applications over the web.
• C# derives much of the power from the .NET
framework on which it runs.
• The .NET framework provides an environment for
building, deploying and running web services(ASP.NET)
and other application (windows application).
• It is an important component that supports building
and running the advanced application and XML
services.
.NET PLATFORM
• .NET
.NE
BUILDING
.NET DEVICE
BLOCK SERVICES
SOFTWARE
.NET USER
EXPERENCE
.NET
INFRASTRUCTURE
AND TOOLS
It consist of three distinct
technologies: CLR, framework base
class and the top layer consist
contains a set of classes for
developing web services and to deal
with the user interface.
.NET FRAMEWORK
ARCHITECTURE.
NET INFRASTRUCTURE AND TOOLS
VISUAL STUDIO
.NET
WINDOWS .NET
.NET EXPERINCE
SERVICES
.NET
FRAMEWORK
.NET FRAMEWORK
WEB SERVICES
WINDOWS FORM
WEB FORMS
DATA & XML CLASSES (ADO.NET,SQL)
WINDOWA
FRAMEWORK BASE CLASS
(I/O, STRONG SECURITY, COLLECTION
ETC)
COMMON LANGUAGE RUNTIME
(DEBUG,EXCEPTION HANDLING,TYPE
CHECKING,JIT,COMPILEER)
WINDOWS PLATFORM
.NET Framework
C#
VB.NET
C++.NET
Other
Common Language Specification
Framework Class Library
ASP.NET
Web Services
Windows Forms
Web Forms
ASP.NET Application Services
Controls
Drawing
Windows Application Services
ADO.NET
XML
Threading
IO
Network
Security
Diagnostics
Etc.
Common Language Runtime
Memory Management
Common Type System
Operating System
Lifecycle Monitoring
Visual
Studio
.NET
.
The core feature/objectives of .NET framework
 Provide a better execution environment for reducing
versioning conflicts and saving the deploying time.
 Provide a safe execution environment.
 Provide an object- oriented programming environment.
 Provide a consistent API as well as consistent experience to
developer across widely varying types of applications such
as windows-based applications and web based applications.
 Provide integrity with different type of code.
 Elimination of the performance problems of scripted or
interpreted environment.
 it is a complete set of tools for building ASP web
application,xml web services, desktop application and
mobile application.
 VB .NET,VB C++ .NET, VB C#.NET and VB J# .NET all uses the
same integrated development environment (IDE),which
allows them to share tools and facilities in the creation of
mixed-language or cross language solution.
.NET framework 4.0 architecture
(feature).
Enhanced globalization.
Garbage collector.
Code contracts.
Design-time-only interop(interoperability)
assemblies.
Memory –mapped files.
Feature of .NET framework and asp.net 4.0
• The main feature are:Enhanced syntax for Html encode.
Enhanced on Microsoft Ajax library.
Session state compression.
Output cache extensibility.
View sate mode for individual controls.
Auto start asp.net application.
Jquery integration.
Execution environment of .NET framework application.
1. ). Common language runtime(CLR).
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Source code
Compiler.
Metadata.
Microsoft Intermediate language(MSIL).
Managed code.
Class loader.
Base class library or.net framework class library.
Just in time compiler(JIT).
Native machine code.
Runtime manager.
 NET Assembly
a. Kinds of assemblies-private and shared.
b. Component of assemblies- manifest, module, type
c. Function of assemblies.
Common language runtime(CLR).
• The common language
runtime(CLR) is one of
the most essential
component of the .NET
framework.
• CLR is a runtime
environment in which all
the programs using .NET
technologies are
executed.
• It also support cross
language compatibility.
COMPONENTS OF COMMON
LANGUAGE RUNTIME(CLR)
COMMON TYPE SYSTEM(CTS)
INTEMIDIATE LANGUAGE(IL)
EXECUTION SUPPORT FUNCTION
SECURITY
GARBAGE COLLECTION
CLASS LOADER
MEMORY LAYOUT
• Contd..
• The CLR provides services such as: Loading and execution of programs.
 Memory allocation and memory isolation for application.
 Verification of type safety.
 Compilation of IL into native executable code.
 Providing metadata.
 Memory management(automatic garbage collection)
 Enforcement of security.
 Interoperability with other systems.
 Managing exceptions and errors
 Support for tasks such as debugging and profiling.
Source code
Assembly
Managed code
compiler
IL and Metadata
Metadata Engine
linkers
Other native code
Exe code
Class loader
Verifier test
Basic class library
For type safety
JIT compiler
Native machine
code
Runtime manager
output
Contd…
Flowchart of CLR activities
for executing a program
Contd…
• While executing the program CLR plays an important
role:
 The source code is compiled to IL while the metadata
engine creates metadata information.
 IL and Metadata are linked with other native code if
required and the resultant IL code is saved.
 During execution, the IL code and any requirement
from the base class library are brought together in the
class loader.
 The combined code is tested for type-safety and then
compiled by the JIT compiler to produce native
machine code, which is sent to runtime manager for
execution.
• Contd…
• Source code:• Initially, a programmer writes a program in a
particular programming language. This form of the
program is called the source code or source program.
• Compiler: A compiler is a special program that processes
statements written in a particular programming
language and turns them into machine language or
"code" that a computer's processor uses.
 When we compile a program developed in a language
that targeted the CLR instead of compiling the source
code into machine-level code, at that time the
compiler translates the source code into Microsoft
intermediate language(MSIL)
 This ensure language interoperability.
Microsoft intermediate language(MSIL)
• MSIL or simple IL, is an instruction set into which
all the .NET programs are compiled.
• It contains instructions for
loading,storing,initializing and calling methods.
• It is low level language that the CLR understands.
• When we compile any program written in a CLScompliant language, the source code is complied
into MSIL.
• In addition to IL,.NET includes a host of other
technologies and tools that will enable us to
develop and implement web-based application
easily.
Metadata
• Metadata is data about data and it contains the
description of code such as data types, classes and
interface dependencies, location and the versions of
the components used in the application.
• It also defines the properites,methods and events
associated with each member type.
• It allows for true cross language integration.
• It is always the job of the compiler not the
programmer to produce the latest type metadata.
• Metadata is used by the CLR complaint compilers to
read many aspects of the application in .NET runtime
environment.
IL and metadata constitute as assembly.
IL
SOURCE CODE
+
METADATA
COMPILER
ASSEMBLY
 Assemblies contain metadata ,which describe the
assembly’s internal version number and details of all
the data and object type they contain.
 When we compile a an V.S complaint application, visual
studio .NET create an assembly that is a single file with
the extension .exe or .dll.
•
•
•
•
•
•
.NET Assembly
The net assembly is the standard for components developed
with the Microsoft .NET .
The .NET assemblies may or may not be excutable,i.e they
might exist as the executable (.exe) file or dynamic link library
(dll) file.
All the .NET assemblies contain the definition of types,
versioning information for the type,meta-deta and manifest.
The assemblies can be used by single or multiple applications.
An assembly can be a single file or it may consist of the
multiple files. in case of multi file, there is one master module
containing the manifest while other assemblies exist as non
manifest modules.
A module in .NET is a sub part of a multi file .NET assembly.
Assembly is one of the most interesting and extremely useful
areas of .NET architecture along with reflections and
attributes.
Component of assemblies- manifest, module, type
Manifest
module
Metadata
IL code
type
Properties , field,
method
•
Manifest: describe the assembly ,it
contains information like name and
version number of the assembly,
security permission required by the
assembly.
• Module: is either a dll or exe file. It
contains IL and metadata.
• Type : is a class that contains data
and logic affecting the data. These
class contains information like
propreties,fields and methods.
Kinds of assemblies-private and shared.
• There are two kinds of assemblies in .NET described below;
• 1. private assemblies: private assemblies are simple and normally used
by a single application, and are stored in the application’s directory.
These assemblies are often used to deploy language-specific
assemblies work in side-by-side execution because the application has a
separate product id for each language and installs satellite assemblies in
a language specific subdirectory for each language.
• 2. shared assemblies: a shared assembly is normally stored in the
global assembly cache, which is a repository of assemblies maintained
by the .NET runtime. for all calling assemblies within the application,
the same copy of the shared assembly is used from its original location.
Hence shared assemblies are not copied in the private folders of each
calling assembly. Each shared assembly has a four part name including
its face name, version ,public key token and culture information. the
public key token and version information makes it almost impossible for
two different assemblies with the same name or for two similar
assemblies with different version to mix with each other.
Function of assemblies.
Supports execution.
Provides security
Support deployment.
Provide unique identification.
Tracks version.
Managed code
• As we know that CLR is responsible for managing the
execution of code compiled for .NET platform.
• The code that satisfies the CLR ,the foundation of the
.NET Framework at runtime in order to execute is
referred to as managed code.
• Managed code supplies the metadata necessary for the
CLR to provide services such as memory management,
cross-language integration, code access security, and
automatic lifetime control of objects. All code based on
IL executes as managed code.
• Compiler that are compatible to .NET platform generates
managed code
• The managed code generated by compiler is called IL
code.
Class loader
• When we execute the .exe or .dll file, the code
which is converted into IL and all the other
relevant information from the base class
library is sent to class loader.
• The class loader loads the code into the
memory.
Base class library or.net framework class library.
• The .NET framework class library is a collection of
reusable types that tightly integrated with the CLR.
• These are inbuilt classes which makes development
very easy.
• The .NET class library is unique for framework that
means we have to study it once and we use it for any
.NET language based application development.
• These are object oriented class from which our own
manage code can derived functionality.
• It enable us to accomplished range of common
programming task such as data collection,database
connectivity, string management etc.
• We can use class library for development of console
application,windows application,ASP.NET
application,XML web services etc.
JIT-manage code execution
• Before the code can be executed, the .NET framework
needs to convert the IL into native or CPU-specific
code.
• The just-in-time complier translates the code from IL
into managed native code.
• During the process of compliation,the JIT compiler
compiles the code that is required during execution
instead of compiling the complete IL code.
• When an uncompiled method is invoked during
execution, the JIT compiler converts the IL for that
method into native code.
• During JIT compilation, the code is also checked for
type safe.
Type-safe
• This feature ensures that the objects are
always accessed in compatible way. Therefore,
the CLR will prohibit a code from assigning a
10-byte value to an object that occupies 8byte.
• Type safety also ensures that objects are
safely isolated from each other and therefore
safe from any malicious corruption.
Native machine code
• Native code is computer programming (code)
that is compiled to run with a particular
processor and its set of instructions.
Runtime manager
• After translating the IL into native code,the
converted code is sent to the .NET runtime
manager.
• The .NET runtime manager executes the code.
• While executing the code, a security check is
performed to ensure that the code has the
appropriate permission for accessing the
available resources.
.NET platform-Security management
• In case of .NET platform, security is achieved
through the code access security(CAS) model.
• In this model, the CLR enforces restriction on
managed code through the use of object
called permission.
• The CLR allow the code to perform only those
tasks for which it has permission.
• In other words, the CAS model specifies what
the code can access instead of specifying who
can access resources.
6. Execution environment of .NET framework
application…CONTD…
(2). Common language specification(CLS).
(3). Common type system(CTS).
(4). Garbage collector(GC).
(5). How the garbage collector works.
(6). Namespace
Common type system(CTS)
• The .NET framework provides multiple language
support using the features known as common
type system(CTS) that is built into CLR.
• CTS support a variety of type and operation
found in most programming languages and
therefore does not required type conversion.
• CTS defines how data types are declared, used
and managed in the code at runtime.
• The CTS also defines the rules that ensure that
the data types of objects written in various
languages are able to interact with each other.
Common language specification(CLS)
• CLR consists of a set of common rules followed
by all the languages of the .NET framework. This
set of rules is known as common language
specification(CLS).
• CLs defines a set of rules that enables
interoperability on the .NET platform.
• These rules serves as a guide to the third-party
compiler, designers and library builders.
• CLS enable an object or application to interact
with the object or application of other language.
• The class that follow the rules specified by CLS
are termed as CLS compliant class.
• The classes defined in the .NET framework class
library are CLS compliant.
Garbage collector(GC).
• The garbage collector is a tool for memory
management provided by .NET framework.
• The garbage collector(GC) runs in a low-priority
thread and checks for un-reference dynamically
allocated memory space.
• If it finds some data that is no more referenced
by any variable/reference, it re-claims it and
returns the occupied memory back to the
operating system so that it can be used by other
programs as necessary.
• The presence of standard garbage collector free
the programmer from keeping track of slack data.
How the garbage collector works.
• The garbage collector examines how objects are arranged in memory and
identify all those objects that can be used by the running programme by
using some references. When a garbage collection starts ,it looks at a set
of references called the ‘gc roots’. These are memory locations that are
designated to be always reachable for some reason, and which contain
references to objects created by the program. It marks these objects as
‘live’ and then looks at any objects that they refrence;it marks these as
being ‘live’ too. It continues in this manner, iterating through all of the
object it knows are ‘live'. it marks anything that they reference are also
being used until it can find no other objects.
•
An object is identified, by the garbage collector, as referencing another
object if it, or one of its super classes that contains the other object. once
all of these live objects are known, any remaining objects can be discarded
and the space can be re-used for new objects. the net reduces memory so
that there will be no gap which means that free memory is always located
at the end of a heap and makes allocating new objects very fast. If an
object has a finalizer,it is not immediately removed when the garbage
collector decides it is no longer ‘live'. these objects usually require more
than one garbage collection to be removed from memory, as they will
survive the first time they are found to be unused.
Benefits of the .NET approach:
• Microsoft has advanced the .NET strategy in order to
provide a number of benefits to developer and user.
• Some of the benefits are: Simple and faster system development.
 Rice object model.
 Enhanced builting-in functionality.
 Many different ways to communicate with the outside
world.
 Integration of different languages into one platform.
 Easy deployment and execution.
 Wide range of scalability.
 Interoperability with existing applications.
 Simple and easy-to-build sophisticated development tools.
 Fewer bugs.
 Potentially better performance.
Application that are supported by the .NET platform
•
•
•
•
•
•
•
Console application.
Windows application.
Developing windows control.
Developing ASP.NET project.
Creating web controls.
Providing web services.
Developing .NET component library.