Learn C# Programming

C# is a simple & powerful object-oriented programming language developed by Microsoft. C# can be used to create various types of applications, such as web, windows, console applications, or other types of applications using Visual studio.

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C# Version History

C# was first introduced with .NET Framework 1.0 in the year 2002 and evolved much since then. The following table lists important features introduced in each version of C#:

Version	.NET Framework	Visual Studio	Important Features
C# 1.0	.NET Framework 1.0/1.1	Visual Studio .NET 2002	Basic features
C# 2.0	.NET Framework 2.0	Visual Studio 2005	Generics Partial types Anonymous methods Iterators Nullable types Private setters (properties) Method group conversions (delegates) Covariance and Contra-variance Static classes
C# 3.0	.NET Framework 3.0\3.5	Visual Studio 2008	Implicitly typed local variables Object and collection initializers Auto-Implemented properties Anonymous types Extension methods Query expressions Lambda expressions Expression trees Partial Methods
C# 4.0	.NET Framework 4.0	Visual Studio 2010	Dynamic binding (late binding) Named and optional arguments Generic co- and contravariance Embedded interop types
C# 5.0	.NET Framework 4.5	Visual Studio 2012/2013	Async features Caller information
C# 6.0	.NET Framework 4.6	Visual Studio 2013/2015	Expression Bodied Methods Auto-property initializer nameof Expression Primary constructor Await in catch block Exception Filter String Interpolation
C# 7.0	.NET Core 2.0	Visual Studio 2017	out variables Tuples Discards Pattern Matching Local functions Generalized async return types more..
C# 8.0	.NET Core 3.0	Visual Studio 2019	Readonly members Default interface methods Using declarations Static local functions Disposable ref structs Nullable reference types more..
C# 9.0	.NET 5.0	Visual Studio 2019	Records Init-only properties Top-level statements Init accessors and readonly fields With-expressions Value-based equality more..
C# 10.0	.NET 6.0	Visual Studio 2022	Record structs Global using directives File-scoped namespace declaration Extended Proptery Patterns Null Parameter Checking Constant interpolated strings more..

Learn how to setup a development environment for C# .

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First C# Program

Here, you will learn to create a simple console application in C# and understand the basic building blocks of a console application.

C# can be used in a window-based, web-based, or console application. To start with, we will create a console application to work with C#.

Open Visual Studio (2017 or later) installed on your local machine. Click on File -> New Project... from the top menu, as shown below.

From the New Project popup, shown below, select Visual C# in the left side panel and select the Console App in the right-side panel.

In the name section, give any appropriate project name, a location where you want to create all the project files, and the name of the project solution.

Click OK to create the console project. Program.cs will be created as default a C# file in Visual Studio where you can write your C# code in Program class, as shown below. (The .cs is a file extension for C# file.)

Every console application starts from the Main() method of the Program class. The following example displays "Hello World!!" on the console.

Example: C# Console Application

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace CSharpTutorials
{
    class Program
    {
        static void Main(string[] args)
        {
            string message = "Hello World!!";

            Console.WriteLine(message);
        }
    }
}

The following image illustrates the important parts of the above example.

Let's understand the above C# structure.

1. Every .NET application takes the reference of the necessary .NET framework namespaces that it is planning to use with the using keyword, e.g., using System.Text.
2. Declare the namespace for the current class using the namespace keyword, e.g., namespace CSharpTutorials.FirstProgram
3. We then declared a class using the class keyword: class Program
4. The Main() is a method of Program class is the entry point of the console application.
5. String is a data type.
6. A message is a variable that holds the value of a specified data type.
7. "Hello World!!" is the value of the message variable.
8. The Console.WriteLine() is a static method, which is used to display a text on the console.

Note:

Every line or statement in C# must end with a semicolon (;).

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Compile and Run C# Program

To see the output of the above C# program, we have to compile it and run it by pressing Ctrl + F5 or clicking the Run button or by clicking the "Debug" menu and clicking "Start Without Debugging". You will see the following output in the console:

Output:

Hello World!!

So this is the basic code items that you will probably use in every C# code.