Gradually Introducing Nullability in Legacy Code: A Practical Guide for .NET and C#
As developers, we’re often tasked with maintaining and modernizing legacy codebases that were written long before some of the best practices of today—such as nullability annotations—were available. While modern C# now supports nullable reference types, enabling us to avoid the dreaded NullReferenceException, introducing this feature to existing, large codebases can be a challenge.
In this article, I’ll share my step-by-step approach for introducing nullability into a legacy .NET and C# project. You’ll learn how to apply nullability in a controlled, incremental manner using project-level settings, scoped annotations, and file/method-level directives, all while maintaining the integrity of your legacy codebase. After all, modernizing your code doesn’t have to be an all-or-nothing endeavor—gradual change is key to a successful transition. Let’s get started!
