What is .NET?

1️⃣ What is .NET?

🔹 .NET (Dotnet) is a free, open-source, cross-platform framework developed by Microsoft for building various types of applications, including:

• Web Applications
• Desktop Applications
• Cloud Services
• Mobile Apps
• Game Development
• IoT Applications

🔹 Key Characteristics of .NET
✅ Cross-platform – Runs on Windows, macOS, and Linux
✅ Language Interoperability – Supports multiple languages, including C#, F#, and VB.NET
✅ High Performance – Optimized runtime for fast execution
✅ Managed Code – Uses the Common Language Runtime (CLR)
✅ Automatic Memory Management – Uses Garbage Collection (GC)

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2️⃣ Evolution of .NET

• .NET Framework (2002) – The original, Windows-only version
• .NET Core (2016) – A cross-platform, modular, open-source version
• .NET 5+ (2020-Present) – A unified platform (merging .NET Framework and .NET Core)

🔹 Current Version: .NET 8 (Latest as of 2024)
🔹 Major Components of .NET

• .NET Runtime – Executes C# applications
• .NET SDK – Tools for building, running, and publishing applications
• ASP.NET Core – Framework for web applications
• Entity Framework Core (EF Core) – ORM for database interactions
• ML.NET – Machine learning framework

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3️⃣ Understanding the Common Language Runtime (CLR)

The CLR (Common Language Runtime) is the heart of .NET that:

• Compiles C# code into Intermediate Language (IL)
• Uses Just-In-Time (JIT) Compilation to convert IL into machine code
• Provides Garbage Collection (GC) for automatic memory management
• Handles Exception Management & Security

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4️⃣ Understanding the .NET Libraries

🔹 Base Class Library (BCL) – A set of built-in classes for:

• Data Types & Collections (string, List<T>, Dictionary<K,V>)
• File & I/O Operations (File, StreamReader, StreamWriter)
• Networking (HttpClient, Socket)
• Threading & Parallel Execution (Task, Thread, Parallel)

🔹 NuGet Packages – Additional libraries you can install from NuGet Package Manager
Example:

dotnet add package Newtonsoft.Json

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5️⃣ Introduction to C#

🔹 C# (C-Sharp) is a modern, object-oriented programming language developed by Microsoft for building applications on the .NET platform.

🔹 Why Learn C#?
✅ Easy to Learn – Clean syntax, similar to Java and C++
✅ Strongly Typed – Helps catch errors at compile-time
✅ Object-Oriented – Supports encapsulation, inheritance, and polymorphism
✅ Versatile – Used in web, desktop, mobile, and game development
✅ Backed by Microsoft – Continuous improvements and community support

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6️⃣ C# Compilation Process

🔹 C# Code Execution Flow:
1️⃣ C# Code (.cs file) ➝ Compiled into Intermediate Language (IL)
2️⃣ IL Code ➝ Executed by the .NET CLR using Just-In-Time (JIT) Compiler
3️⃣ Machine Code ➝ Runs on the CPU

Example:

using System;

class Program
{
    static void Main()
    {
        Console.WriteLine("Hello, .NET and C#!");
    }
}

🔹 Compile and Run:

dotnet run

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7️⃣ C# Language Features

✔ Variables & Data Types (int, double, string, bool, object)
✔ Control Flow (if, switch, for, while)
✔ Functions & Methods (Method Overloading, Recursion)
✔ OOP Principles (Encapsulation, Inheritance, Polymorphism, Abstraction)
✔ Asynchronous Programming (async/await, Task<T>)
✔ Exception Handling (try, catch, finally)
✔ LINQ (Language Integrated Query) (from x in list where x > 10 select x)

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8️⃣ Frameworks & Technologies Built with C#

🔹 Web Development – ASP.NET Core
🔹 Desktop Applications – WPF, WinForms, MAUI
🔹 Mobile Development – .NET MAUI, Xamarin
🔹 Game Development – Unity (Uses C# as scripting language)
🔹 Cloud Computing – Azure Functions, Serverless Apps
🔹 Machine Learning – ML.NET
🔹 Database Development – Entity Framework Core, Dapper

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9️⃣ C# Development Tools

🔹 Integrated Development Environments (IDEs):

• Visual Studio (Recommended)
• Visual Studio Code
• JetBrains Rider

🔹 Package Managers:

• NuGet (for libraries)
• .NET CLI (dotnet add package <package-name>)

🔹 Debugging Tools:

• Visual Studio Debugger
• dotnet trace, dotnet dump

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🔚 Conclusion

Understanding .NET and C# is the foundation for becoming a skilled C# developer. Once you're comfortable with these concepts, you can move on to deeper topics like object-oriented programming, async programming, databases, and web development with ASP.NET Core.