Hands-On: Structural Design Patterns in C#

Structural design patterns are often misunderstood as academic theory, but getting them right is crucial for building maintainable and scalable C# systems. This course moves beyond the textbook definitions to show you how to solve concrete software architecture problems, one pattern at a time. We’ll start with the Adapter pattern, tackling the common issue of mismatched interfaces by exploring both Object Adapter via Composition and Class Adapter via Inheritance. From there, you’ll see how the Bridge pattern decouples abstraction from implementation to prevent a class explosion, and how the Composite pattern simplifies operations on tree-like structures so you can stop writing manual traversal logic. You’ll learn to avoid a subclass explosion with the Decorator pattern, building a practical HTTP Middleware Pipeline as a capstone. We’ll then simplify complex subsystems with the Facade pattern, manage memory-intensive objects with shared state using the Flyweight pattern by separating intrinsic and extrinsic state, and control object access through different Proxy implementations, including Virtual, Protection, and Caching proxies.

The real power of these patterns emerges when they are combined, and this course culminates by showing you exactly how to do that. The final modules move from isolated examples to larger, practical applications where multiple patterns work together. You will build an API Gateway that combines the Facade and Adapter patterns, an Org Report system using Composite and Bridge, and an Audit Pipeline that leverages both Proxy and Decorator. The course concludes with a comprehensive Document Publishing system that integrates all seven structural patterns, giving you a complete picture of how these concepts apply to real-world C# development.