From Problems to Patterns: Domain-Driven Design and Event Sourcing in .NET: Understanding the Patterns, One Problem at a Time

About This BookThis book teaches Domain-Driven Design (DDD) and Event Sourcing through a single, continuously evolving example: a Bank Account system built in C# with .NET. Rather than introducing patterns as abstract theory, every pattern arrives as the solution to a concrete problem the reader has already experienced in code. The book begins with a naive CRUD implementation that visibly breaks under real-world conditions, then systematically rebuilds it across 32 chapters using DDD strategic patterns, tactical patterns, Event Sourcing, CQRS, and production infrastructure.The reference implementation uses SourceFlow.Net v1.0.0 as the Event Sourcing framework, introduced at the midpoint of the book after the reader has built equivalent infrastructure by hand.Target Audience- .NET developers with experience in C# and ASP.NET Core who are new to DDD and Event Sourcing- Teams adopting DDD who need a practical, code-first learning path rather than abstract theory- University students and thesis writers using DDD/Event Sourcing as a foundation for academic work (dedicated sidebars throughout)
Not for: Absolute .NET beginners (C#, ASP.NET Core, and EF Core are assumed) or advanced DDD practitioners seeking treatment of exotic patterns.Book Structure32 chapters across 7 parts, each following a consistent five-beat structure: Core Concept, Design Decision, Hands-On Implementation, Test, and What We Built.Part Chapters Focus
I - Thinking in Domains: 1-6 Strategic DDD: Ubiquitous Language, Bounded Contexts, Value Objects, Aggregates, Domain Events
II - Modelling with Events: 7-11 Building Event Sourcing by hand: append-only logs, sequencing, persistence, replay, snapshots
III - Commanding Change: 12-16 Framework adoption (SourceFlow.Net), Commands, Command Pipeline, Sagas, Compensation
IV - Reading the World: 17-22 Event Pipeline, Read Models, Projections, Eventual Consistency, Validation, Projection Rebuild
V - Infrastructure & Persistence: 23-26 Three-store architecture, EF Core integration, Schema Evolution, End-to-End testing
VI - Production Readiness: 27-29 Polly resilience, OpenTelemetry tracing, Docker containerisation
VII - Inside the Framework: 30-32 Framework internals, Custom stores (MongoDB), Cloud dispatch (AWS SQS)Plus 7 appendices: API reference, glossary, feature progress matrix, dev setup guide, migration guide, further reading, and thesis support guide.