C#

Build games, apps, and enterprise software with C# — 67 lessons from first program to advanced .NET architecture.

A complete C# course — syntax, OOP, LINQ, collections, async and .NET fundamentals — with interactive lessons for beginners and beyond.

Part of the free C# course at LearnCodingFast — hands-on lessons with examples you run in your browser, plus practice exercises and a quick quiz.

👋 New to C#? Start here — no experience needed.

C# powers Unity games, Windows apps, and enterprise backends. Start with Lesson 1 and build from scratch.

Lessons in this course

• Introduction to C# — What C# and .NET are, and how to write and run your first program
• Variables & Data Types — int, string, bool, double — declare and use the core C# types
• Data Types — Value vs reference types, ranges, and choosing the right type
• Type Casting & Boxing — Implicit/explicit casts, Convert, and boxing/unboxing
• User Input (Console.ReadLine) — Read and parse keyboard input from the console
• Strings, Interpolation & StringBuilder — String methods,
  quot;interpolation", and efficient StringBuilder
• Generic Lists (List<T>) — The go-to resizable collection — add, find, sort, loop
• Dictionary (Key-Value Pairs) — Fast key-value lookups with Dictionary
• Properties & Auto-Properties — get/set, auto-properties, init and computed properties
• Enums — Named constant sets, flags, and parsing
• Checkpoint: C# Basics — Combine input, collections and strings in a build challenge — then a quiz
• Nullable Types & Null Operators — Nullable<T>, ?? , ?. and ??= for safe null handling
• Pattern Matching & Switch Expressions — Modern switch expressions, type/property patterns
• Records — Concise immutable data types with value equality and with-expressions
• Structs (struct vs class) — Value types — when to use a struct over a class
• Tuples & Deconstruction — Return multiple values and deconstruct them
• Extension Methods — Add methods to existing types without inheritance
• DateTime — Work with dates, times, spans and formatting
• Regular Expressions — Match and extract text with Regex
• Checkpoint: Types & Data — Combine records, patterns and extensions in a build challenge — then a quiz
• Operators — Arithmetic, comparison, logical, and null-coalescing operators in C#
• Control Flow — Control your program's logic with if, else, switch, and ternary expressions
• Loops — Iterate with for, foreach, while, and do-while loops
• Methods — Write reusable methods, use optional parameters, and understand scope
• Object-Oriented Programming — Create classes with properties, constructors, and encapsulation
• Inheritance & Polymorphism — Extend base classes and override methods with virtual and override
• Collections — Work with List<T>, Dictionary<K,V>, Stack, Queue, and more
• Exception Handling — Handle errors gracefully with try-catch-finally and custom exceptions
• LINQ — Query collections and databases with clean, readable LINQ expressions
• Async & Await — Write responsive, non-blocking code with async/await and Task<T>
• Delegates & Events — Build event-driven programs with delegates, Action, Func, and events
• File I/O — Read and write files, streams, and structured data with System.IO
• Advanced LINQ Queries & Optimization — GroupBy, SelectMany, deferred execution, and LINQ performance tuning
• Deep Dive Into C# Delegates & Multicast Delegates — Delegate internals, multicast chaining, and Func/Action composition
• Events: Advanced Patterns & Custom EventArgs — Custom EventArgs, weak event patterns, and event-driven architecture
• Expression Trees: Building Dynamic Logic at Runtime — Build and compile expression trees for dynamic query and code generation
• Reflection & Dynamic Type Inspection — Inspect assemblies, types, and members dynamically with the Reflection API
• Generics: Constraints, Variance & Advanced Use Cases — Type constraints, covariance, contravariance, and generic patterns
• Asynchronous Programming Internals (Tasks, Schedulers, States) — State machine compilation, SynchronizationContext, and task schedulers
• Parallel Programming with PLINQ & Parallel.For — Parallelise CPU-bound workloads safely with PLINQ and Parallel class
• Memory Management & Garbage Collector Internals — Generational GC, Large Object Heap, GC modes, and finalizers
• Unsafe Code, Span<T>, and High-Performance C# — Use Span<T>, Memory<T>, and unsafe code for zero-allocation hot paths
• IDisposable, Finalizers & Resource Management — Implement IDisposable correctly, use using declarations, and avoid leaks
• Advanced OOP Patterns (Factory, Strategy, Observer, DI) — Apply GoF patterns and DI principles in real C# applications
• Dependency Injection Internals in .NET — How .NET DI works, service lifetimes, and custom DI containers
• Logging Architecture (ILogger, Providers, Serilog) — Structured logging with ILogger, Serilog sinks, and log enrichment
• Working with Files: Streams, Buffers, Pipelines — High-performance I/O with StreamReader, BufferedStream, and System.IO.Pipelines
• Advanced JSON Processing with System.Text.Json — Serialise, deserialise, and customise JSON processing without Newtonsoft
• Building REST APIs with ASP.NET Core (Advanced) — Minimal APIs, controller patterns, model binding, and versioning
• Middleware, Filters & Custom Attributes in ASP.NET — Write custom middleware, action filters, and attributes for cross-cutting concerns
• Entity Framework Core Internals & Performance — How EF Core tracks entities, batches queries, and generates SQL
• EF Core Relationships, Tracking & Migrations Mastery — One-to-many, many-to-many, owned entities, and migration strategies
• Repository Pattern & Unit of Work (Advanced) — Implement repository and unit of work patterns in clean .NET architecture
• Authentication & Authorization with JWT (Advanced) — Issue, validate, and refresh JWTs in ASP.NET Core APIs
• Role-Based, Policy-Based & Claims-Based Security — Implement RBAC, custom policies, and claims transformation in .NET
• Caching Strategies (MemoryCache, Distributed Cache, Redis) — Add in-memory and distributed caching with IMemoryCache and Redis
• Real-Time Communication with SignalR — Build live dashboards and chat with SignalR hubs and JavaScript clients
• WebSockets & Streaming Data in .NET — Handle raw WebSocket connections and stream large data in .NET
• Unit Testing Mastery (xUnit, NUnit, MSTest) — Write clean, maintainable tests with xUnit, NUnit, and assertions
• Mocking Frameworks (Moq, NSubstitute, FakeItEasy) — Mock dependencies with Moq, set up expectations, and verify calls
• Test-Driven Development in Real Projects — Apply Red-Green-Refactor TDD to real C# feature development
• Clean Architecture in .NET (Full Deep Dive) — Layer your .NET app into Domain, Application, Infrastructure, and Presentation
• Domain-Driven Design (Aggregates, Value Objects, Repositories) — Apply DDD tactical patterns to model complex business domains in C#
• Microservices in .NET (gRPC, Messaging, Resilience) — Build .NET microservices with gRPC, MassTransit, Polly, and Docker
• Background Jobs with Hangfire & Quartz.NET — Schedule and run background tasks reliably with Hangfire and Quartz.NET
• Performance Profiling & Benchmarking (BenchmarkDotNet) — Measure and optimise .NET performance with BenchmarkDotNet and dotTrace
• Final Project — Enterprise-Grade C# Application — Build a complete enterprise-style application applying everything you've learned
• Game Development with Unity & C# — Build games with GameObjects, MonoBehaviour, prefabs and physics in Unity
• Desktop Apps with WPF & XAML — Create Windows desktop apps with XAML, data binding and the MVVM pattern
• Web UIs with Blazor — Build interactive web UIs in C# with Razor components, binding and DI
• Nullable Reference Types — Compile-time null safety with #nullable, string? and flow analysis
• Iterators with yield return — Build lazy IEnumerable<T> sequences with yield return and yield break
• Configuration & the Options Pattern — IConfiguration, appsettings binding and IOptions<T> in ASP.NET Core
• Concurrency with Channels — Producer/consumer pipelines with System.Threading.Channels and backpressure

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