CSharp-Coder

Learn how to build a recommendation system in C# using ML.NET collaborative filtering. Step-by-step tutorial with full code — start building today. Every time Netflix suggests your next binge or Amazon shows you "customers also bought," you're seeing a recommendation system at work. These systems drive an enormous share of engagement and revenue for the world's biggest platforms — and thanks to ML.NET, you can build a production-ready recommendation system in C# without leaving the .NET ecosystem or writing a single line of Python. In this tutorial, you'll build a movie recommendation engine using collaborative filtering with ML.NET's matrix factorization trainer. We'll cover the theory (just enough to make smart decisions), the full working code, how to evaluate your model, and the pitfalls that trip up most developers on their first attempt. What Is a Recommendation System and How Does Collaborative Filtering Work? A recommendation system pre...