Global Usings and Implicit Usings

Every C# file used to start with a tall stack of using directives that looked nearly the same across the whole project. System, System.Collections.Generic, System.Linq, System.IO, repeated in file after file. C# 10 added two features that cut most of that boilerplate: the global using directive, and the project-level <ImplicitUsings> switch in the csproj. This lesson covers what each one does, how the compiler resolves a name when both are in play, when global usings make a codebase cleaner, and when they make it harder to read.