--- title: "Representing void methods with generic delegates" url: "https://osherove.com/blog/2005/10/27/representing-void-methods-with-generic-delegates.md" canonical: "https://osherove.com/blog/2005/10/27/representing-void-methods-with-generic-delegates.html" published: "2005-10-27T14:20:00" updated: "2005-10-27T14:20:00" tags: [".Net 2.0"] author: "Roy Osherove" description: "Generics are cool. Learn about them . I want to talk about a specific query that I had which right now I can only guess the answer. To begin, here's the scenario. You can create a Generic Delegate to point to a method…" usage: "Licensed under CC BY 4.0 — reuse, quote and adapt with attribution (Roy Osherove, link to the original page)." license: "https://creativecommons.org/licenses/by/4.0/" --- # Representing void methods with generic delegates By Roy Osherove October 27, 2005 In [.Net 2.0](https://osherove.com/blog/category/net-2-0) **Historical article** · Originally published October 27, 2005; technical details may be outdated. Generics are cool. [Learn about them](http://msdn2.microsoft.com/en-us/library/0x6a29h6.aspx). I want to talk about a specific query that I had which right now I can only guess the answer. To begin, here's the scenario. You can create a Generic Delegate to point to a method you want to execute. For example this simple method : **void myMethod(int number)** you could create a generic delegate: **delegate void invokeDelegate(T input)** can invoke it like this: **invokeDelegate invoker = myMethod;** _(I'm using the new c# 2.0 syntax that allows me to create an "inferred delegate" instead of writing "**new invokeDelegate(myMethod)**" )_ it even cool if the method had a return type like this: **bool myMethod(int number)** you could create a generic delegate: **delegate RET invokeDelegate(T input)** and invoke it thusly: **invokeDelegate invoker = myMethod;** but how do you take the delegate I've just written and apply it to the \*first\* method which returns a void? Turns out you can't, at least from my poking around. The more I thought about it the more it makes sense. If you allow a "void" type to be used as generic type parameter, it is implied that this parameter can be used not only as a return value but as a parameter to the generic function/delegate itself. Here's what someone \*could\* write if this was possible: **delegate void invokeDelegate(T input,RET moreinput)** assuming someone does this (if the compiler allowed it): **invokeDelegate invoker = myMethod;** it would have to implicitly mean that there's a method somewhere looking like this: **void myMethod(int number,void IhaveNoIdeaWhatThisIs)** which means, in essence, that to represent all method signatures you'd always need at least two generic delegates, one void and one with a generic return value. That's just my line of thinking, but I'd love for someone from MS to comment on this. ## More in .Net 2.0 [All posts in .Net 2.0](https://osherove.com/blog/category/net-2-0) - Oct 30, 2005 ### [Amazoner 1.0.1 - Larger Images for Books and a dedicated website](https://osherove.com/blog/2005/10/30/amazoner-101-larger-images-for-books-and-a-dedicated-website.html) - Oct 30, 2005 ### [Strongly Typed Reflection Calls in .NET 2.0](https://osherove.com/blog/2005/10/30/strongly-typed-reflection-calls-in-net-20.html) - Oct 21, 2005 ### [Nice Guidance Automation kit hands on lab from TechEd (with a fix for a build problem it contains)](https://osherove.com/blog/2005/10/21/nice-guidance-automation-kit-hands-on-lab-from-teched-with-a.html) - Oct 19, 2005 ### [Early experiences from .NET 2.0 Winforms](https://osherove.com/blog/2005/10/19/early-experiences-from-net-20-winforms.html) --- ## About the author **Roy Osherove**: Senior Solutions Architect at AWS working on AI for production and AI-driven development; author of The Art of Unit Testing and Elastic Leadership, with about 20 years of consulting and training on unit testing, TDD, team leadership and continuous delivery. ### Sites - [RobotPaper](https://robotpaper.ai/): This blog: AI patterns and anti-patterns, AI and coding agents, and engineering leadership. - [osherove.com](https://osherove.com): Roy's personal site. Author of The Art of Unit Testing and Elastic Leadership; consulting and training on unit testing, TDD, team leadership and continuous delivery, plus about 20 years of blog posts. - [The Art of Unit Testing](https://www.artofunittesting.com): The Art of Unit Testing, 3rd Edition (Manning): readable, maintainable, trustworthy unit tests, plus TDD workshops in C#, JavaScript, Java and Kotlin. - [5whys.com](https://www.5whys.com): Roy's writing on software team leadership: self-organizing teams, surviving chaos, learning mode and the Elastic Leadership model. - [Pipeline Driven](https://pipelinedriven.org): Continuous delivery and DevOps practices: build patterns, pipeline-friendly testing, DevOps metrics and enterprise DevOps. - [Elastic Leadership](https://www.elasticleadership.com): Elastic Leadership, Roy's framework for software team leaders (survival, learning and self-organizing modes). ### Social - X: https://x.com/royosherove - LinkedIn: https://www.linkedin.com/in/osherove/ ### Contact - Contact form: https://forms.gle/jQSx5KoXvrVA1JCK7 ### License Licensed under CC BY 4.0 — reuse, quote and adapt with attribution (Roy Osherove, link to the original page). License: https://creativecommons.org/licenses/by/4.0/