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C#: Types, Asynchrony, and Runtime Contracts

Build precise C# programs and reason about nullability, collections, async lifetimes, memory, and concurrency.

18 lessonsEnglish + ArabicContent reviewed
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In this course

This complete language and runtime course develops C# from console programs and typed expressions to generics, LINQ, asynchronous operations, Span, garbage collection, concurrency, and secure API boundaries. Each level contains six substantial lessons, with explained examples, diagnosis records, and worked exercises.

The course focuses on C# and .NET rather than a web framework. Demonstrations use synthetic data and platform libraries, with no real database, cloud account, or external service. Operational examples explain contracts without deploying anything.

What you will learn

  • Explain C# types, null-state analysis, value copying, and object references.
  • Design generic and LINQ operations with explicit enumeration contracts.
  • Build cancellable asynchronous operations and bounded I/O.
  • Review memory lifetimes, synchronization, API compatibility, and measured performance.

Your learning path

Three levels

Basic: Typed Programs and Object Contracts

Read and construct C# console programs with clear values, control, collections, and failure behavior.

  1. The C# Toolchain and Program Model
  2. Types, Conversions, and Nullability
  3. Control Flow and Method Contracts
  4. Collections, Strings, and Bounds
  5. Classes, Interfaces, and Invariants
  6. Exceptions and Deterministic Resource Cleanup
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Intermediate: Composition and Asynchronous Work

Compose generics, LINQ, asynchronous operations, cancellation, I/O, and meaningful tests.

  1. Generics and Collection Contracts
  2. LINQ and Deferred Enumeration
  3. Async, Await, and Task Lifetimes
  4. Cancellation and Operation Lifetimes
  5. Bounded I/O and Serialization
  6. Testing and Debugging Contracts
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Advanced: Lifetimes, Concurrency, and Runtime Design

Justify memory and synchronization rules and carry them into maintainable, measurable APIs.

  1. Value Semantics, References, and Garbage Collection
  2. Span, Memory, and Borrowed Lifetimes
  3. Concurrency and Synchronization
  4. API Design, Immutability, and Compatibility
  5. Profiling and Measured Performance
  6. Security and Runtime Release Boundaries
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Who this is for

  • New C# learners who can edit text and run local development commands.
  • Developers reviewing null safety, asynchronous control flow, collection semantics, and runtime behavior.

Before you start

  • Basic programming familiarity helps, but the basic level explains its core concepts.
  • Complete preceding levels or bring equivalent knowledge before advanced lessons.

Related technical solutions

Resolve NullReferenceException and Nullable WarningsRestore the object construction and absence contract rather than suppressing a warning at the eventual dereference.Resolve Async Blocking and Cancellation GapsIdentify the continuation or operation that cannot progress, then repair asynchronous composition and completion ownership.Resolve Collection, Concurrency, and Lifetime ErrorsDistinguish invalid enumeration, shared-state races, and expired resource leases before choosing a contextual repair.