The document outlines the features and components of the .NET framework, including the Common Language Runtime (CLR), Common Type System (CTS), and Common Language Specification (CLS). It discusses various types of applications that can be developed using .NET, as well as the role of assemblies and namespaces in the framework. Additionally, it highlights the evolution of .NET, its architecture, and key functionalities such as memory management and type safety.

1. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.1
C# Programming
Unit -1

2. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.2
• The CLR and .NET Framework: Understand the
motivation behind the .NET platform,
• Common Language Infrastructure (CLI).
• Common Type System (CTS),
• Common Language Specification (CLS)
• Common Language Runtime (CLR),
• Assembly, metadata, namespace, type distinction,
Contrast single-file and multi-file assemblies,
• Common Intermediate Language (CIL),
• Platform independent .NET(Mono / Portable .NET
distributions).
Objectives

3. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.3
What is .NET :
• A robust development and
runtime environment.
• A platform for building fast web
and desktop applications.
• Programming language
agnostic. A set of specifications
submitted to ECMA to allow
ports to non-Windows
operating systems.
• A runtime that provides
memory management and
type verification.

4. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.4
What is the .NET Framework?
• The .NET Framework is a new and revolutionary
platform created by Microsoft for developing
applications.
• It is a platform for application developers.
• It is a Framework that supports Multiple Language
and Cross language integration.
• It has IDE (Integrated Development Environment).
• Framework is a set of utilities or can say building
blocks of your application system.

5. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.5
• .NET is a platform independent but with help of Mono
Compilation System (MCS). MCS is a middle level
interface.
• .NET Framework provides interoperability between
languages i.e. Common Type System (CTS) .
• .NET Framework also includes the .NET Common
Language Runtime (CLR), which is responsible for
maintaining the execution of all applications
developed using the .NET library.
• The .NET Framework consists primarily of a gigantic
library of code.
.NET Framework Contd…

6. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.6
.Net framework Architecture Diagram

7. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.7
.NET components
• Common Type System (CTS): A standard that
specifies how Type definitions and specific
values of Types are represented in computer
memory. It is intended to allow programs written in
different programming languages to easily share
information.
• Common Language Specification (CLS): A set of
base rules to which any language targeting the
CLI should conform in order to interoperate with
other CLS-compliant languages. The CLS rules
define a subset of the Common Type System.

8. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.8
.NET components Contd..
• Common Language Runtime (CLR): A library of
utility classes for building desktop, web, or any type
of application, as well as a runtime for
executing .NET code with garbage collection and
type verification.
• Common Intermediate Language (CIL): All .NET
languages compile to this platform-independent
language.
• Assemblies: A new name and structure for EXE
and DLL files.

9. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.9
Representation of CLS and CLR

10. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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Common Type System (CTS)

11. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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Common Type System -CTS
The common type system defines how types are
declared, used, and managed in the common
language runtime, and is also an important part of
the runtime's support for cross-language integration.
The common type system performs the following
functions:
1.Establishes a framework that helps to enable
cross-language integration, type safety, and high-
performance code execution.

12. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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Common Type System -CTS
2. Defines rules that languages must follow, which
helps ensure that objects written in different
languages can interact with each other.
3. Provides a library that contains the primitive data
types (such as Boolean, Byte, Char, Int32, and
UInt64) used in application development.
4. Provides an object-oriented model that supports
the complete implementation of many
programming languages.

13. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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What type of applications can I develop?
1. ASP.NET Web applications
2. Windows Form based applications
3. Console applications
4. Component Libraries
5. Windows Custom Controls
6. Windows Services
7. Web Custom Controls
8. Web services

14. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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Features of .NET
• Rich Functionality out of the box
• Easy development of web applications
• OOPs Support
• Multi-Language Support
• Multi-Device Support
• Automatic memory management
• Compatibility with COM and COM+
• Strong XML support
• Ease of deployment and configuration
• Security

15. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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Release History
Version Version Number Release Date Visual Studio Default in Windows
1.0 1.0.3705.0 2002-02-13 Visual Studio .NET
Windows XP Tablet and
Media Center Editions[4]
1.1 1.1.4322.573 2003-04-24 Visual Studio .NET 2003 Windows Server 2003
2.0 2.0.50727.42 2005-11-07 Visual Studio 2005
Windows Server 2003
R2
3.0 3.0.4506.30 2006-11-06
Windows Vista,
Windows Server 2008
3.5 3.5.21022.8 2007-11-19 Visual Studio 2008
Windows 7, Windows
Server 2008 R2
4.0 4.0.30319.1 2010-04-12 Visual Studio 2010

16. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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.NET Framework version history
• Windows Presentation
Foundation (or WPF)
• Windows
Communication
Foundation (or WCF)
• Language Integrated
Query (or LINQ)

17. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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Class Library
• The Base Class Library (BCL) includes a small
subset of the entire class library and is the core set of
classes that serve as the basic API of the Common
Language Runtime.
• The classes in mscorlib.dll and some of the classes
in System.dll and System.core.dll are considered to
be a part of the BCL.
• The BCL classes are available in both .NET
Framework as well as its alternative implementations
including .NET Compact Framework, Microsoft
Silverlight and Mono.

18. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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Base Class Libraries

19. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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Common Language Runtime
• The Common Language Runtime (CLR) is an Execution
Environment .
• The main function of Common Language Runtime (CLR)
is to convert the Managed Code into native code and
then execute the Program.
• It works as a layer between Operating Systems and the
applications written in .Net languages that conforms to the
Common Language Specification (CLS).
• The Common Language Runtime (CLR) 's Just In Time
(JIT) compilation converts Intermediate Language (MSIL)
to native code on demand at application run time.

20. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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CLR- Execution Model
Execution Model

21. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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Assembly
Assembly
Compilation And Execution
Source
Source
Code
Code
Language
Language
Compiler
Compiler
Compilation
Compilation
At installation or the
At installation or the
first time each method
first time each method
is called
is called
Execution
Execution
JIT
JIT
Compiler
Compiler
Native
Native
Code
Code
Code (IL)
Code (IL)
Metadata
Metadata

22. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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CLR

23. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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Components of CLR
• Class Loader: This loads classes into the runtime.
• MSIL to native code compiler: This converts MSIL code into native code.
• Code manager: This manage the code during execution i.e provides code
check, the resources it needs during execution.
• Garbage Collector: provide automatic memory management and avoid
memory leaks.
• Security Engine: This enforces security restrictions and CAS.
• Type Checker: This enforces strict type checking.
• Thread Support: This provides multithreading support to applications.
• Exception Manager : This provides a mechanism to handle the run-time
exceptions.
• Debug Engine : Allow you to debug different type of applications.
• COM marshaler : This allows .net application to exchange data with COM
applications.
• BASE Class library : This provides the types the applications needed at
runtime.

24. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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The CLR Architecture
Class Loader
MSIL to Native
Compilers (JIT)
Code
Manager
Garbage
Collector (GC)
Security Engine Debug Engine
Type Checker Exception Manager
Thread Support COM Marshaler
Base Class Library Support

25. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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What is an assembly?
An Assembly is a logical unit of code
• Assembly physically exist as DLLs or EXEs
• One assembly can contain one or more files
• The constituent files can include any file types like image files, text
files etc. along with DLLs or EXEs
• When you compile your source code by default the exe/dll
generated is actually an assembly
• Unless your code is bundled as assembly it can not be used in any
other application
• When you talk about version of a component you are actually
talking about version of the assembly to which the component
belongs.
• Every assembly file contains information about itself. This
information is called as Assembly Manifest.

26. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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Functions or Features:
• It contains the code that a CLR executes.
• MSIL code in a portable executable file will not be
executed if it doesn't contain the associated
assembly manifest.
• Each assembly can have only one entry point( that
is DllMain, WinMain, Main )
• It forms a security boundary. An assembly is a unit
at which permissions are requested and granted.
• Type Boundary: Every type identity includes the
name of the assembly in which its resides.

27. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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Features Contd..
• Reference Scope Boundary: The assembly manifest
contains assembly metadata that is used for resolving
types and satisfying resources requests.
• Version Boundary: The assembly is the smallest
versionable unit in the CLR, all types and resources in the
same assembly are versioned as a unit.
• It forms a deployment unit: When an application starts,
only the assemblies that the application initially calls must
be present. Other assemblies, such as localization
resources or assemblies containing utility classes can be
retrieved on demand.

28. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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There are three types of assembly.
1.Private Assembly
2.Shared Assembly
3.Satellite Assembly
Types of Assembly

29. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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Types of Assembly
1. Private Assembly:-
These are those assemblies, which are used by single
application and are stored in the application directory or a
sub-directory beneath.
• Here the scope of this assembly is limited to the application
itself and this assembly can't be shared by multiple
assemblies.
• If you want to use this private assembly, you have to either
copy this assembly or paste under the bin folder or you
can create the reference of this assembly using the Add
reference dialog box and use this assembly.
• The limitation with the private assembly is that it can't be
accessed by two application.

30. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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Types of Assembly Contd…
2. Shared Assembly:-
• A shared assembly can be used by multiple
assemblies.
• A shared assembly is normally stored in GAC
(Global Assembly Cache), which is a repository of
assemblies maintained by the .Net runtime.
• Shared assemblies are usually libraries of code
which many applications will find useful e.g. crystal
report classes which will be used by all application
for reports.

31. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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Types of Assembly Contd…
3. Satellite Assembly:-
• In multi lingual application in .Net to support
multilingual functionality you can have modules
which are customized for locations.
• These assemblies are called as satellite
assemblies. Here in these assemblies we can
distribute these assemblies separately than the
core modules.

32. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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Namespace
• A collection of related set of classes, structures, enumerators etc.
• It is similar to package in Java.
• All C# applications are developed using classes from the .NET
System namespace.
• The namespace with all the built-in C# functionality is the System
namespace.

33. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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Some Important Namespaces
• System: Includes essential classes and base classes for commonly
used data types, events, exceptions and so on
• System.Collections: Includes classes and interfaces that define
various collection of objects such as list, queues, hash tables, arrays,
etc
• System.Data: Includes classes which lets us handle data from data
sources
• System.Data.OleDb: Includes classes that support the OLEDB .NET
provider
• System.Data.SqlClient: Includes classes that support the SQL
Server .NET provider
• System.Diagnostics: Includes classes that allow to debug our
application and to step through our code
• System.Drawing: Provides access to drawing methods

34. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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Namespaces Contd…
System.Globalization: Includes classes that specify culture-related information
System.IO: Includes classes for data access with Files
System.Net: Provides interface to protocols used on the internet
System.Reflection: Includes classes and interfaces that return information about
types, methods and fields
System.Security: Includes classes to support the structure of common language
runtime security system
System.Threading: Includes classes and interfaces to support multithreaded
applications
System.Web: Includes classes and interfaces that support browser-server
communication
System.Web.Services: Includes classes that let us build and use Web Services
System.Windows.Forms: Includes classes for creating Windows based forms
System.XML: Includes classes for XML support

35. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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Role of the Common Language Infrastructure
(CLI)
• When C# and the .NET platform were released to the world
at large, Microsoft Corporation submitted two formal
specifications to ECMA (European Computer
Manufacturers Association).
• Once approved, these same specifications were submitted
to the International Standards Organization (ISO) and
ratified shortly thereafter.
The two specifications are:
• ECMA-334, which defines the syntax and semantics of the
C# programming language.
• ECMA-335, which defines numerous details of the .NET
platform, collectively termed the Common Language
Infrastructure (CLI).

36. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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Common Language Infrastructure
• CLI allows for cross-language development.
• Four components:
Common Type System (CTS)
Meta-data in a language agnostic fashion.
Common Language Specification – behaviors that all
languages need to follow.
A Virtual Execution System (VES).

37. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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Common Language Infrastructure
• The purpose of the Common Language Infrastructure is to
provide a language-neutral platform for application
development and execution, including functions for
Exception handling, Garbage Collection, security, and
interoperability.
• By implementing the core aspects of the .NET Framework
within the scope of the CLI, this functionality will not be tied
to a single language but will be available across the many
languages supported by the framework. Microsoft's
implementation of the CLI is called the Common Language
Runtime, or CLR.

38. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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Common Language Infrastructure
The CLI specification describes the following four
aspects
• The Common Type System (CTS) A set of data
types and operations that are shared by all CTS-
compliant programming languages.
• Metadata : Information about program structure is
language-agnostic, so that it can be referenced
between languages and tools, making it easy to
work with code written in a language you are not
using.

39. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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Common Language Infrastructure
• Common Language Specification (CLS) A set of
base rules to which any language targeting the CLI
should conform in order to interoperate with other
CLS-compliant languages. The CLS rules define a
subset of the Common Type System.
• Virtual Execution System (VES) The VES loads
and executes CLI-compatible programs, using the
metadata to combine separately generated pieces
of code at runtime.

40. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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CLR versus CLI.
• CLR is actually an
implementation by
Microsoft of the CLI
(Common Language
Infrastructure) .
• CLI is an open
specification.
• CLR is really a platform
specific implementation.

41. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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Role of CIL
• .NET language compilers do not emit native platform code. Rather, they
emit platform-independent instructions called the Common Intermediate
Language (CIL).
• Unlike Java bytecode, CIL is not interpreted. It is just-in-time compiled
(JITed) at runtime. You may see CIL referred to by a few other names:
IL or MSIL.

42. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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What is Mono/ Platform independent
• Mono is a software platform
designed to allow developers to
easily create cross platform
applications.
• It is an open source implementation
of Microsoft's .Net Framework
based on the ECMA standards for
C# and the Common Language
Runtime.

43. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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MONO
• Mono can be run on Android, BSD, iOS, Linux, Mac
OS X, Windows, Solaris, and Unix operating
systems as well as some game console operating
systems such as the ones for the PlayStation 3, Wii
, and Xbox 360.
• Mono is a free and open source project led by
Xamarin (formerly by Novell and originally by
Ximian) to create an Ecma standard
compliant .NET-compatible set of tools including,
among others, a C# compiler and a Common
Language Runtime.

44. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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The Components
There are several components that make up Mono:
• C# Compiler - Mono's C# compiler is feature complete for C# 1.0, 2.0,
3.0, and 4.0 (ECMA).
• Mono Runtime - The runtime implements the ECMA Common
Language Infrastructure (CLI). The runtime provides a Just-in-Time (JIT)
compiler, an Ahead-of-Time compiler (AOT), a library loader, the
garbage collector, a threading system and interoperability functionality.
• Base Class Library - The Mono platform provides a comprehensive set
of classes that provide a solid foundation to build applications on. These
classes are compatible with Microsoft's .Net Framework classes.
• Mono Class Library - Mono also provides many classes that go above
and beyond the Base Class Library provided by Microsoft. These
provide additional functionality that are useful, especially in building
Linux applications. Some examples are classes for Gtk+, Zip files,
LDAP, OpenGL, Cairo, POSIX, etc.

45. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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Mono Environment for Linux

46. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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Mono for MAC

47. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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Mono Open Source for all

48. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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Mono for Android

49. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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The Benefits
There are many benefits to choosing Mono for application
development:
• Popularity - Built on the success of .Net, there are millions of
developers that have experience building applications in C#. There
are also tens of thousands of books, websites, tutorials, and
example source code to help with any imaginable problem.
• Higher-Level Programming - All Mono languages benefit from
many features of the runtime, like automatic memory management,
reflection, generics, and threading. These features allow you to
concentrate on writing your application instead of writing system
infrastructure code.
• Base Class Library - Having a comprehensive class library
provides thousands of built in classes to increase productivity.
Need socket code or a hashtable? There's no need to write your
own as it's built into the platform.

50. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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The Benefits
• Cross Platform - Mono is built to be cross platform. Mono
runs on Linux, Microsoft Windows, Mac OS X, BSD, and Sun
Solaris, Nintendo Wii, Sony PlayStation 3, Apple iPhone. It
also runs on x86, x86-64, IA64, PowerPC, SPARC (32), ARM,
Alpha, s390, s390x (32 and 64 bits) and more. Developing your
application with Mono allows you to run on nearly any computer in
existence.
• Common Language Runtime (CLR) - The CLR allows you to
choose the programming language you like best to work with, and
it can interoperate with code written in any other CLR language.
For example, you can write a class in C#, inherit from it in VB.Net,
and use it in Eiffel. You can choose to write code in Mono in a
variety of programming languages.

51. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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Short Questions
• What is Common Language Infrastructure (CLI) .Explain
the role of it?
• What is Common Type System (CTS) explain with
points?
• What is Common Language Specification (CLS) give
some points?
• Write some difference point between class library and
console application projects?
• What is managed and unmanaged code with diagram?
• What is namespace ? Explain the use of any five
namespaces?
• What is JIT compiler and write the types of it ?

52. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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Short Questions
• What is the role of Common Type System (CTS) ?
• What is Common Language Specification (CLS)
Explain ?
• Write short notes on the following:
1.Assembly
2.metadata
3.namespace
4.type distinction
• What is managed and unmanaged code?
• What is JIT compiler and explain the types of it?

53. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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Long Questions
• What is .NET frame work. Explain the architecture
of it ?
• Explain the working of Common Language
Runtime?
• What are the features of .NET framework ?
• What is assembly, explain the type of assembly in
detail?
• What is Mono project explain the Portable .NET
distributions of it ?
• What is common language specification explain in
detail?

54. © Bharati Vidyapeeth’s Institute of Computer Applications and Management, New Delhi-63, by Uttam Singh, Asst. Professor U2.
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References
Books:
• The Complete Reference C# 4.0 ,Tata Mc Graw –Hill Edition,
Herbert Schildt [Herbert Schildt]
• C# 2010 for Programmers, Pearson Education, Paul J. Deitel,
Harvey M. Deitel [Paul]
Web:
• http://download.microsoft.com/download/8/e/7/8e725d96-7ec3-
498b-9fa7-86779aed101f/dotnet%20tutorial%20for%20beginners.pdf
• http://www.visualbuilder.com/dotnet/tutorial
• http://www.c-sharpcorner.com/