Introduction

Okay.. i have decided to make this a tutorial-like blog (for now..) so if you want to learn from the very basics this is just the place to start!

Do comment on mistake you see, i try to provide the best information according to my knowledge... Thanks.

Basic requirements you'll need

• A Integrated Development Environment (IDE)
  I would recommend using Visual Studio or Visual C# Express
  If you don't have one you can download the Visual C# Express IDE for free
• .NET Framework installed

Basic Information

So what exactly is C#?

C# is a simple, modern, object-oriented and type-safe programming language created by Microsoft for the .NET Framework platform.

So what is the .NET Framework?

According to Wikipedia, The Microsoft .NET Framework is a software technology that is available with several Microsoft Windows operating systems

If you do not care about the .NET Framework or find the next section confusing and just want to continue to the coding parts you can skip this post now (hopefully come back later on).
Do read on if you want to know more about the .NET framework or find references on the web. Remember that if you wish to be a better/successful .NET programmer it is important to know about the .NET Framework!

More about .NET Framework

.NET Framework is a set of tools and services. The main items of .NET Framework consists of the following: Common Language Specification (CLS), Common Type System (CTS), Framework Class Library (FCL) and Common Language Runtime (CLR)

Diagram: .NET Framework architecture (taken from codeguru.com)

As you can see from the diagram, C# is not the only language that supports the .NET Framework, but C# is the first language to be created specifically for the .NET Framework! and that is something to be proud of =).

Now i am going to explain briefly on the important components of the .NET Framework if you need a complete specification i suggest you to look up on MSDN.

Common Language Specification (CLS)

Common Language Specifications is a set of base rules that any language targeting the Common Language Infrastructure/.NET must follow. It works with the CTS to ensure language interoperability.

The Common Language Infrastructure is a set of standards defined so that applications written in multiple high-level languages that targets it can be executed in different system environment (different platform: Windows, Linux) without the need to rewrite the application.

Common Type System (CTS)

CTS is a standard that describe a set of type for basic primitive datatypes (eg. String, Integer, Floating Types) in which languages that target the .NET Framework should map (eg.int in C# and Integer in VB.NET both maps to Int32 in the CTS) to for interoperability (interact/share information/communicate) with other languages.

Thus, with aid of CTS, interoperability standards are way better than before, it means that you can actually see the transfer of execution when for example a C# application calls a VB.NET library function which makes debugging applications made in more than one language way simpler.

Framework Class Library (FCL)

The Framework Class Library is a set of libraries with common and useful methods you can use. As you will see later on is one of the biggest advantage you get being a .NET developer, it includes a very very wide range of libraries that you will most likely be using.

Common Language Runtime (CLR)

Finally! Common Language Runtime the last and most important core feature of the .NET Framework. The CLR is the .NET Framework's runtime execution environment. Application codes that run under the management of the CLR are termed as managed code.

Diagram: Managed vs Unmanaged code

Normal applications that compile directly to machine specific code are called unmanaged code whereas applications that compile through the .NET compiler are called managed code (IL code).

From the above diagram, the blackbox surrounding the JIT Compiler and x86 Machine Code is part where the CLR manages the execution of the application.

Therefore, there is two steps of compilation for .NET applications

1. Source code to IL code
2. IL code to platform specific code

By using this method there are several advantages.

1. You get platform independence, the IL code can be placed on another platform before they are compiled to machine specific code by the runtime. Although there is no Microsoft implementation at this time of writing. The Mono Project enables .NET programmers to have their codes portable to platforms such as Linux and Mac.
2. Under the management of CLR, you get a performance improvement as machine codes are generated in a method-by-method basis during which means that functionaility that you do not need to use during runtime will not be compiled to machine code, you save time and space on the compilation process
3. With the JIT compilation on the target machine (the machine that runs the application) the CLR knows exactly what platform it is running on, this way it can perform code optimization for that specific platform.

The CLR itself contains the following services

• Garbage collector(GC) - Automatically remove data in the memory that are no longer needed.
• Exception handling - Handles errors or conditions that changes the normal way of execution in a clean manner.
• Security - Provides many security features such as role management.
• Thread management - Manages thread execution

More about C#

The C# project is started during December 1998 (More than 10 years ago) with the goal of creating a programming language that is simple, modern, object-oriented and type-safe for the .NET platform (Not named at that time).

Currently, C# (Currently at version 3.0, 4.0 is releasing soon...) has grow so much with over a million programmers programming with it.

C# compiles to IL code (managed application) and runs under the control of CLR.
So some of you might be thinking "Will this affect the performance?". Unfortunately its a yes, managed applications runs slower than unmanaged applications because of all the type-checking and management but the amount of speed difference is very very little you should not worry about unless you need to program a mission critical application. If so, you should program with languages like C++ instead.

So why would you want to use .NET/C#?
I would say that you get far more benefits which will outweigh the performance loss. With features such as the Garbage Collection you would not have to worry about memory management yourself (unless you use resources that do not belong to you) and the type-checking feature of the CTS you get less prone to bugs/errors in your application. And most importantly you get to use a set of ready made libraries developed with the best design available!

I will end here for now, if there should be anything anyone wish to add or change do post a comment. I do not have the time and ability to cover everything.. Sorry!