Learn C# 💡

Learn C# in a structured, docs-first way.

This repository is built for learners who want more than scattered syntax notes or disconnected code snippets. It follows the official Microsoft C# and .NET documentation as the source of truth, but explains the ideas in a slower, more connected order with examples, practical notes, and companion notebooks.

What This Repository Includes 📚

• guided lessons under docs 📖
• interactive notebook companions under notebooks 📓
• a practical learning path from C# foundations through syntax, control flow, methods, object-oriented programming, advanced language features, LINQ, asynchronous programming, Roslyn, and .NET runtime topics 🧭
• concept-first explanations that help beginners, developers coming from other languages, and working engineers build a stronger mental model before jumping into framework-specific code 🧠

Table of Contents 🗂️

• 00 Introduction
• 01 Getting Started
  • 01 What Is C#?
  • 02 Why Learn C#?
  • 03 C# and .NET
  • 04 Language Versions
  • 05 Installation and Setup
  • 06 SDK and CLI Basics
  • 07 IDEs: VS Code and Visual Studio
  • 08 Your First Program
  • 09 How C# Runs Code
  • 10 How To Run C# Programs
• 02 Core Syntax and Types
  • 01 Variables and Naming
  • 02 Built-in Value Types
  • 03 Reference Types and Nullability
  • 04 Type Conversion and Casting
  • 05 Operators and Expressions
  • 06 Strings and Characters
  • 07 Arrays
  • 08 Lists
  • 09 Dictionaries
  • 10 Sets
  • 11 Tuples
  • 12 Enums
  • 13 Input and Output
• 03 Statements and Flow Control
  • 01 Statements and Blocks
  • 02 Selection Statements
  • 03 Pattern Matching
  • 04 Iteration Statements
  • 05 Jump Statements
  • 06 Exception-handling Statements
  • 07 checked and unchecked
  • 08 using and Dispose Patterns
  • 09 lock Statement
  • 10 yield Statement
• 04 Members, Methods, and Functions
  • 01 Methods
  • 02 Method Parameters
  • 03 Optional and Named Arguments
  • 04 Return Values
  • 05 Expression-bodied Members
  • 06 Local Functions
  • 07 Lambda Expressions
  • 08 Delegates
  • 09 Events
  • 10 Extension Methods
• 05 Namespaces, Projects, and Organization
  • 01 Namespaces
  • 02 using Directives
  • 03 Access Modifiers
  • 04 Classes
  • 05 Structs
  • 06 Records
  • 07 Interfaces
  • 08 Generics
  • 09 Projects and Assemblies
  • 10 NuGet Packages and References
• 06 Object-Oriented C#
  • 01 Objects and Instances
  • 02 Fields and Properties
  • 03 Constructors
  • 04 Inheritance
  • 05 Polymorphism
  • 06 Abstract Classes
  • 07 Interfaces in Practice
  • 08 Operator Overloading
  • 09 Indexers
  • 10 Object and Collection Initializers
• 07 Advanced Language Features
  • 01 Pattern Combinators
  • 02 Nullable Reference Types
  • 03 Attributes
  • 04 Preprocessor Directives
  • 05 Unsafe Code and Pointers
  • 06 Span and Memory Overview
  • 07 User-defined Conversions
  • 08 Overload Resolution Overview
  • 09 Anonymous Types
  • 10 dynamic and Reflection Overview
  • 11 Nullable Value Types
  • 12 Caller Information Attributes
  • 11 Nullable Value Types
  • 12 Caller Information Attributes
• 08 Practical C#
  • 01 LINQ Basics
  • 02 async and await
  • 03 Exception Design
  • 04 File and Directory Basics
  • 05 Serialization with System.Text.Json
  • 06 Testing Basics
  • 07 Documentation Comments
  • 08 Configure Language Version
  • 09 Whats New in Recent C# Versions
  • 10 Next Steps and References
• 09 LINQ and Data Queries
  • 01 LINQ Overview
  • 02 Query Expressions and Method Syntax
  • 03 LINQ to Objects and Deferred Execution
  • 04 IQueryable, Expression Trees, and Providers
  • 05 LINQ Operators Overview
  • 06 LINQ to XML
  • 05 LINQ Operators Overview
  • 06 LINQ to XML
• 10 Asynchronous Programming
  • 01 async and await Fundamentals
  • 02 Starting and Coordinating Tasks
  • 03 Composing Async Workflows
  • 04 Async Exceptions and Task Composition
• 11 C# How-To Guides
  • 01 Strings and Text Processing
  • 02 Type Conversion and Parsing
  • 03 Equality and Ordering
  • 04 Collections and Initializers
  • 05 Delegates, Events, and Command-Line Input
  • 06 Dates, Times, and Formatting
  • 06 Dates, Times, and Formatting
• 12 Roslyn and Code Analysis
  • 01 Roslyn SDK Overview
  • 02 Syntax and Semantic Analysis
  • 03 Analyzers and Code Fixes
  • 04 Source Generators and Workspaces
• 13 What's New in C#
  • 01 Language Versioning and Compatibility
  • 02 What's New in C# 12
  • 03 What's New in C# 13
  • 04 What's New in C# 14 and C# 15
• 14 .NET Platform and Runtime
  • 01 .NET Platform Overview
  • 02 Runtime, CLR, and Managed Execution
  • 03 Common Type System and Base Class Library
  • 04 Target Frameworks, TFMs, and .NET Standard
  • 05 .NET SDK, Project System, and MSBuild
  • 06 NuGet Packages and Dependency Management
  • 07 Configuration, Dependency Injection, and Generic Host
  • 08 Logging, Diagnostics, and Observability
  • 09 Memory Management, Garbage Collection, and Resources
  • 10 Threading, Tasks, and Parallel Programming
  • 11 Publishing, Deployment, and Versioning
  • 12 Security, Cryptography, and Safe Code
  • 13 Streams and IO
  • 14 Collection Interfaces and Specialized Collections
  • 15 Synchronization and Shared State
  • 16 Parallel Processing and Data Parallelism
  • 17 Networking, URIs, and HttpClient
  • 18 Assemblies, Reflection, and Metadata
  • 19 Regular Expressions

Notebooks 📓

The notebooks folder contains hands-on companions to the main lessons.

• Notebook Companions README
• Notebook Introduction

Use docs/ for the full explanations and notebooks/ for runnable examples and small experiments.

References 🔗

• C# Language Reference
• .NET Fundamentals
• .NET Documentation
• .NET CLI Overview
• .NET Runtime Libraries
• .NET Diagnostics
• C# Language Versioning
• System.Text.Json
• NuGet Documentation

License 📄

This repository is licensed under the MIT License.

See the LICENSE.md file for the full information.