C#8 Nullable Reference in Practice

Tuesday, 10 March 2020

Talk Description

"The most significant new feature of C# 8.0 is its support for non-nullable references. In a bid to mitigate what is often described as the “billion dollar mistake” of allowing references to be null, C#’s language designers have attempted to retrofit the ability to write code that declares unambiguously that it doesn’t want nulls, and for the compiler to attempt to enforce that for you. Adding such a feature almost two decades into the life of the language and its supporting runtime was always going to be challenging, so this feature has quite a few quirks (such as its apparently inverted name). In this talk, Ian Griffiths will describes the ins and outs of the new feature, with particular reference to his employer, endjin’s experience with applying this new feature to existing code. In addition to an in-depth description of the technical details of nullable references, this talk will also describe strategies for migrating an existing codebase into the world of nullability-awareness.”

Speaker Bio

"Ian started using computers when he was six. He has worked in various aspects of computing, including computer networking, embedded real-time systems, broadcast television systems, medical imaging, and all forms of cloud computing. He is a Technical Fellow at endjin. He is the author of O’Reilly’s Programming C# 8.0. You can follow him on Twitter via @idg10."


  • Photos (thanks to John Parkin from Ocean Software for taking these!)


Thanks to Pusher for recording this for us!


Speaker's Links

Some public projects endjin have been converting to use nullable references types:

Some useful links from the docs:


  • Corriculo Recruitment - Kindly covering the venue, drinks, and helping us at each event
  • Everstack - Dan's company, helping organise and manage the user group
  • JetBrains - Prize draw sponsor (any JB product the winner likes)
  • Manning Books - Prize draw sponsor (ebook of winner's choice)
  • New Orbit - Prize draw sponsor (Raspberry Pi Starter Kit)
  • Pusher - Video recordings

News Items

Prize Draw Winners

  • Jetbrains: Hoi
  • Manning ebook: Daniel B
  • Raspberry Pi Starter Kit (New Orbit): Agamemnon