Design Patterns in C# 15

Write C# software that is easier to extend, test, and maintain-without adding patterns your application does not need.

Knowing a pattern's name is not the same as knowing when to use it. Mastering Design Patterns: Practical architecture with C# 14 and .NET 10 connects the classic patterns to the decisions developers face as requirements change: how to create objects, separate responsibilities, manage behavior, and preserve clear contracts.

Across 29 chapters, you will explore all 23 Gang of Four design patterns, plus Object Pool. C# implementations, application examples, diagrams with Mermaid source, practical exercises, and tradeoff discussions help you understand both the structure of a pattern and the problem it is meant to solve.

Inside, you will learn to:

• Apply object-oriented and SOLID principles to define clearer responsibilities and more useful abstractions.
• Choose among creational, structural, and behavioral patterns instead of treating every design problem alike.
• Follow a recurring fictional commerce application through checkout, pricing, export, and fulfillment scenarios.
• Evaluate lifetimes, mutable state, ownership, and failure cases before adapting an example.
• Connect patterns with generics, LINQ, concurrency, thread safety, and reflection.
• Bring several patterns together in an integrated checkout workshop.
• Recognize when a constructor, a delegate, or a small switch is simpler than another abstraction.

Who this book is for
Developers who already understand basic C# methods, collections, and control flow and want to strengthen their software-design skills. The opening chapters refresh the object-oriented foundations needed for the examples; this is not a first introduction to programming.

The examples distinguish teaching implementations from production infrastructure, making their limits part of the lesson rather than hiding them.

Go beyond memorizing a catalog. Learn to choose, implement, and question design patterns with confidence.