TechnicalcodewithAJ

Introduction to .NET

*.NET framework was introducted by microsoft in the year 2002.

*.NET framework is a software development framework for building and running applications on windows.

*Microsoft introduced .net framework for bridging gap between applications by providing interoperability(Interoperability means the ability of two or more languages to interact as a part of the same system).

*Various types of applications we can develop by using the .net framework such as console application,windows application,web application,mobile application and many more...

*By using .net we can also create services like web services,WCF services and web api's.

*We can create web applications such as asp.net,MVC,silverlight and many more...

*.NET is a foundation were we can build,design,develop and deploy the application.

*.NET is a framework consists of more than 300+ language characteristics has been formed as a single group, were we can use the features one language into another language.

*We can create our own customized libraries as well.

*.NET framework is a wonderful tool provided by the Microsoft.

*.NET Framework includes a library and run time environment.

*FCL:FCL stands for framework class library.

FCL provides user interface,database connectivity,cryptography(cryptography means it is a art of writing or solving codes),web development and many more...

*Major .net components:

I CLR

II CTS

III CLS

IV MSIL

V JIT

*CLR stands for common language runtime.

CLR performs the following operations:

a.Debbugging:CLR sends the respective compiler to compile the respective code.

b.Exception Handling:Responsible for handling run time errors.

c.Security:Security plays immense role in any kind of application development.

d.Version support:The application developed in lower version can be upgraded automatically to higher version.

*CTS:CTS Stands for common Type System.

CTS describes the datatypes that can be used by managed code.

CTS defines how these types are declared and managed in the runtime.

It provides cross-language integration,type safety and high performance code execution.

CTS deals with the datatype.

*CLS:CLS stands for common language specification and it is subset of CTS.

CLS enables cross-language integration or interoperability.

*MSIL:MSIL stands for Microsoft Intermediate Language.

When we compile any .net application at first instead of converting it into native code or machine code,first it will be converted into MSIL.Then it will become language neutral.

MSIL is also know as CIL(Common intermediate language)

MSIL is also know as Managed code or IL(Intermediate language)

*JIT:JIT stands for Just in Time

JIT compiler converts the MSIL into native code or Machine code which is understandable by the operating system.

Assemblies:

*Assemblies have an extension of .dll or .exe depending on the type of application.

*.Net Assemblies contain Managed code.

*.Non .net Assemblies contain unManaged code.

*Console,Windows applications will have .exe extension after compilation.

*Web application will have .dll extension after compilation.

*.exe or .dll are the intermediate language assembly generated by the respective compilers after program execution.

*When we compile non .net program it will generate the assembly which is it native format it is also known as unManaged code or Machine code which is understandable by the operating system.

*.Net assemblies contain IL or MSIL whereas non .Net assemblies contain Native code or Machine code.

*.Net application execution is performed in two steps:

1. Compilation

2. Execution

*Compilation:from source code to IL or MSIL

*Execution:IL to platform specific machine code or native code.

CLR:Common language runtime environment provides several benefits like:

i. Garbage collection.

ii. Performance improvement.

iii. Interoperability.

iv. Exception Handling.

v. Custom Attributes and many more..

*.Net support many programming language like C#,VB,J# and C++.

*C#,VB,J# can generate only Managed code.

*C++ can generate both Managed and unManaged code.

*The Native code is not stored anywhere in the System, After we close the program the native code is destroyed.

*When we execute the program again the native code gets genterated again.

Program:

using System;

namespace Introtocsharp

{

class Program

{

static void Main()

{

Console.WriteLine("welcome to .net tutorial");

}

INTRODUCTION TO C#

C# is a modern, general-purpose, object-oriented programming language developed

by Microsoft and approved by European Computer Manufacturers Association (ECMA)

and International Standards Organization (ISO).

C# was developed by Anders Hejlsberg and his team during the development of .Net

Framework.

C# is designed for Common Language Infrastructure (CLI), which consists of the

executable code and runtime environment that allows use of various high-level

languages on different computer platforms and architectures.

The following reasons make C# a widely used professional language:

*It is a modern, general-purpose programming language

*It is object oriented.

*It is component oriented.

*It is easy to learn.

*It produces efficient programs.

*It can be compiled on a variety of computer platforms.

*It is a part of .Net Framework.

C# vs .Net

*C# is a progragramming language.

*.Net is a framework for building application on windows.

*.Net framework is not limited to c# programming language,we can build application using different programming languages like J#,vb.net,F# in .Net Framework.

*What is namespace?

Namespace is a collection of classes,interfaces,structures,enums and delegates.

Namespace is used to organize the code.

Namespace can contain other Namespaces.

*Main() method is the entry point into your application.

*What is a class?

Class is a container contains Data & Methods.

Data is also known as Attributes

Method is also known as Functions.

*Functions or Methods have behavior they execute the code.

*Data represents the State of the Application

Creating Hello World Program:

* A C# program consists of the following parts:

* Namespace declaration

* A class

* Class methods

* Class attributes

* A Main method

* Statements and Expressions

* Comments

Let us check with a simple code that prints the words "Hello World":

using System;

namespace Firstcs

{

class Program

{

static void Main()

{

/* my first program in C# */

Console.WriteLine("Hello World");

Console.ReadLine();

}

* When this code is compiled and executed, it produces the following result:

Hello World

* Let us look at the various parts of the given program:

* The first line of the program using System;this using keyword is used to

include the System namespace in the program. A program generally has

multiple using statements.

* The next line has the namespace declaration. A namespace is a collection of

classes. The Firstcs namespace contains the class Program.

* The next line has a class declaration, the class Program contains the data

and method definitions that your program uses. Classes generally contain

multiple methods. Methods define the behavior of the class. However, the

Firstcs class has only one method Main.

* The next line defines the Main method, which is the entry point for all C#

programs. The Main method states what the class does when executed.

* The next line /*...*/ is ignored by the compiler and it is put to add

comments in the program.

* The Main method specifies its behavior with the statement

Console.WriteLine("Hello World");

* WriteLine is a method of the Console class defined in the System namespace.

This statement causes the message "Hello, World!" to be displayed on the

screen.

* The last line Console.ReadLine(); .This makes the program wait for a key press and it prevents the screen from running and closing quickly when the program is launched from Visual Studio .NET.

* Points to be Remembered:

* C# is case sensitive.

* All statements and expression must end with a semicolon (;).

* The program execution starts at the Main method.

C# Keywords:

* Keywords are reserved words predefined to the C# compiler. These keywords cannot

be used as identifiers(identifier can be a class name,method name or variable name). However, if you want to use these keywords as identifiers, you

may prefix them with the @ character.

* In C#, some identifiers have special meaning in context of code, such as get and set,

these are called contextual keywords.

* The following lists the reserved keywords and contextual keywords in C#:

* Reserved Keywords:

1.abstract 2.as 3.base 4.bool 5.break 6.byte 7.case 8.catch 9.char 10.checked

11.class 12.const 13.continue 14.decimal 15.default 16.delegate 17.do 18.double

19.else 20.enum 21.event 22.explicit 23.extern 24.false 25.finally 26.fixed 27.float 28.for 29.foreach 30.goto 31.if 32.implicit 33.in 34.in (generic modifier) 35.int 36.interface 37.internal 38.is 39.lock 40.long 41.namespace 42.new 43.null 44.object 45.operator 46.out 47.out(generic modifier) 48.override 49.params

50.private 51.protected 52.public 53.readonly 54.ref 55.return 56.sbyte 57.sealed 58.short 59.sizeof 60.stackalloc 61.static 62.string 63.struct 64.switch 65.this 66.throw 67.true 68.try 69.typeof 70.uint 71.ulong 72.unchecked 73.unsafe 74.ushort 75.using 76.virtual 77.void 78.volatile 79.while

* Contextual Keywords:

1.add 2.alias 3.ascending 4.descending 5.dynamic 6.from 7.get 8.global 9.group 10.into 11.join 12.let 13.orderby 14.partial(type) 15.partial(method) 16.remove 17.select 18.set

A Contextual Keywords is used to provide a specific meaning in the code, but they are not reserved keywords.