Development with a Dot

These are the posts in the series: Less Known LINQ Methods C# Records Implementing the Strategy Pattern with .NET Dependency Injection .NET 10 Validation Nullable and Required Types Working with Strings in .NET C# Magical Syntax .NET Collections .NET Metrics .NET Cancellation Tokens Service Discovery in .NET Retrieving Services from Dependency Injection in .NET The Evolution of .NET Dependency Resolution Named HttpClient Registrations

Introduction Note: some people complained that what I actually called Dependency Injection is actually Inversion of Control. I won’t get into that fight, to me, Dependency Injection is a form of Inversion of Control. The  Strategy Pattern  (sometimes known as Policy) originated in the seminal book Design Patterns , by the Gang of Four. It is a behavioural design pattern  that allows picking a specific strategy at runtime. The concrete strategy to use can change dramatically how the application behaves. Quoting: instead of implementing a single algorithm directly, code receives runtime instructions as to which in a family of algorithms to use. Dependency Injection (DI), also known as Inversion of Control (IoC) - they’re not quite the same, but, for the purpose of this post, we can think of them as the same, even though this raises heated discussions - is built-in in .NET Core (now, .NET) since the start, and whilst we generally return the same implementation type ...

Note: this is an update of an old post that is no longer available from my old blog . Introduction Dependency Resolution (RS), Dependency Injection/Dependency Inversion (DI) and Inversion of Control (IoC) are hot topics for a long time. Basically all frameworks are aware of it, or offer some mechanisms to help implement it. It all started a long time ago, however, and things are slightly confusing at the moment – but will get better! In this post, I won’t go through all of the details of all dependency resolution libraries in existence, instead I will only focus on Microsoft libraries. Also, I will only talk about generic dependency resolution, leaving out more specialized usages, such as WCF , WF and SharePoint , which also use similar concepts. Origins It all started with the venerable IServiceProvider interface. It basically provided a single method, GetService , that gave answer to “get me an implementation for this type”. That was it, the single parameter was a Type , and the r...