The Strategy pattern helps manage algorithm selection at runtime by encapsulating different implementations behind a common interface. This tutorial demonstrates implementing the pattern in ASP.NET Core using dependency injection, starting with a problematic if-else approach for discount calculations, then refactoring to separate strategy classes (RegularDiscount, VipDiscount, StudentDiscount). The solution uses a factory delegate (Func<string, IDiscountStrategy>) registered in the DI container to resolve strategies dynamically based on customer type, adhering to the open/closed principle and improving maintainability.