C# (.NET 8 LTS) · 22 lessons

Set up the .NET SDK and tooling, then build and run your first C# console application.

Declare variables and work confidently with C# value types, reference types and type inference.

Use C# operators to calculate values, compare results and handle nulls safely.

Branch and repeat work with conditionals, switch expressions and the main loop forms.

Break programs into reusable methods and pass data with overloads, ref modifiers and optional arguments.

Model data and behaviour with classes, constructors and the right access modifiers.

Protect object state with properties, init-only setters, required members and validation.

Reuse and extend existing classes with inheritance, virtual methods and controlled overriding.

Call the right implementation through base references and use casts and abstract classes safely.

Define contracts with interfaces, implement several at once and program against abstractions.

Store fixed-size data in one- and two-dimensional arrays and use Span and Memory for slices.

Choose the right collection for ordered lists, key-value lookups, unique sets, queues and stacks.

Write reusable, type-safe generic code and understand how variance works.

Query collections declaratively with LINQ, from filtering and projection to grouping and aggregation.

Handle failures with try, catch and finally, filter exceptions and throw meaningful errors.

Read and write text files with File, StreamReader and Path while handling I/O failures.

Process text with string methods, interpolation, StringBuilder and regular expressions.

Pass behaviour with delegates and lambdas, and publish or subscribe to events.

Run I/O-bound work asynchronously with Task, await, cancellation and ConfigureAwait.

Turn on nullable reference types and handle nulls with ?., ?? and the null-forgiving operator.

Use modern pattern matching to make type checks and branching safer and clearer.

Create immutable data types with records, init-only setters, value equality and with expressions.