Basic information about C sharp -Dot Net

Some of the questions that always need to know a c# learner before going for the programming in C#. So from today I will write only about c# basics and ahead I will try to bring good articles for the beginners so keep visiting...

let’s start now ......

1. What is .NET?

   It is a platform or technology from Microsoft based on .NET Framework

2. How languages differ from technology?

   In a language things get created from scratch while in a technology things are already available but need to assembled.

What is a framework?

-          A software that provides a set of libraries, a set of tools and some rules

-          Examples

o   MVC (Model-View-Controller) framework

o   Struts

o   Hibernate

o   spring

o   .NET Framework

o   Mono Framework

What are different frameworks for .NET Technology?

-          There are two frameworks available for .NET technology

o   .NET Framework from Microsoft

§  Proprietary

§  Works with Windows Only

§  Supports all possible language under .NET

o   Mono Framework from Novell

§  Open Source

§  Works with all operating systems

§  Supports few languages like C# and Ruby

Is C# Platform Independent?

-          No

-          Since Mono which runs C# on all platform is not from Microsoft

Why .NET?

-         Actually .Net provide cross-Language interoperability among many languages of choice

o   C#

o   VB

o   J#

o   C++

o   F#

o   Pythen.NET

o   Ruby.NET

o   Pascal.NET

o   COBOL.Net

o   Etc.

-          All languages get compiled into a common format called as MSIL (Microsoft Intermediate Language)

-          Only on software is enough to run application written in any .NET based language called as CLR (Common Language Runtime)

-          To make the interoperable programs they must follow CLS (Common Language Specifications) compliancy rules

-          All language share the common libraries and tools provided by special software called .NET Framework

o   .NET Framework software provides different versions of libraries

§  1.0

§  1.1

§  2.0

§  3.0

§  3.5

§  4.0

-          All languages share the Common Type System (CTS). It is set of classes and structures that get mapped by different language based on their size

o   System.Byte

o   System.Int16

o   System.Int32 à C# (int), VB (Integer)

o   System.Int64

o   System.Single à C# (float), VB(Single)

o   System.Double

o   System.Boolean

o   System.String

o   System.Object

-          Single IDE called Visual Studio for any kind of development using any language of choice

o   Versions of Visual Studio

§  2001

§  2003

§  2005

§  2008

§  2010

-          Any kind of development using language of choice

o   Console Application

o   Window Based

o   Web Base

o   Mobile Applications

o   Window Service

o   Web Service

-          Integration other third party technologies

o   AJAX

o   Web Service

o   Web 2.0

-          No more “DLL Hell”

-          All .NET language is Object Oriented

What is the location of frameworks?

C:\Windows\Microsoft.NET\Framework

C# as Programming Language

-          A programming language based on .NET Framework based on C and C++, with the power of Java and simplicity of Visual Basic

-          It is an object Oriented Language

-          Every program should have a class

-          Every executable program  (.exe) must have an entry point

o   public static void Main()

o   public static int Main()

o   public static void Main(string []args)

o   public static int Main(string []args)

-          File must be saved as .cs

Syntactical Rules of C#

-          All keywords must be lower case

-          All other items should start with capital letter

o   It is called as Pascal case

Hierarchy in .NET

Assembly or Dynamic Link Library (DLL) à Namespaces à Classes/Structures àField/Method etc.

Example

MSCorlib.dll à System namespace à Console class à Write(),WriteLine()

Test Case

System.Console.WriteLine("Hello to C#");

Writing First C# (C-Sharp) Program

Class First

{

                public static void Main()

                {

                                System.Console.WriteLine("Hello to C#");

                }

}

Compile the program

-          Use compiler as CSC.EXE

o   CSC <programname>

CSC First.cs à First.exe

Running an executable file

First

Note: If CSC is not working then set the PATH

Look for your framework folder, copy the path, now the set path using DOS

SET PATH=%PATH%; C:\WINDOWS\Microsoft.NET\Framework\v3.5

Setting Path using My Computer à Properties à Advanced à Environmental Variables à System Variables à Path à Edit à Add your path after a semicolon

View contents of an MSIL file

      Use ILDASM (Intermediate Language De-Assembler) tool to view contents of an MSIL file

ILDASM <filename>

Example

ILDASM First.exe

How C# programs execute

.cs à CSC à .exeà CLR à Code Verifier à Just-in-time (JIT) compiler à Native code à Execution

Importing the Namespaces

-          Use using keyword

using <namespacename>;

Example

using System;

class First

{

        public static void Main()

        {

                        Console.WriteLine("Hello to Using");

        }

Creating Aliases to namespace and classes

-          Use the using keyword again

using <aliasname>=<namespace or class>;

Example

//Creating an alias

using c=System.Console;

class First

{

                public static void Main()

                {

                                c.WriteLine("Hello to Alias");

                }

}

Using Visual Studio.NET IDE as RAD (Rapid Application Development) tool

-          Start the Visual Studio.NET 2008

-          Create a new project using Visual C# as language and Console Application as Template

-          Select the location and Type the Project Name as Sample

-          Use Ctrl+F5 to run the programs