Proxy vs Decorator Pattern in C#: Key Differences Explained

A detailed comparison of the Proxy and Decorator design patterns in C#, focusing on their intent rather than their near-identical structure. The proxy controls access to an object (gatekeeping, authorization, lazy init, caching that skips the inner call), while the decorator always delegates and adds behavior (logging, metrics, retry). The post covers lifecycle ownership differences, transparency, DI registration in ASP.NET Core, and how to compose both patterns together. A decision criteria table and FAQ section help developers choose the right pattern for their use case.