Thanks to your excellent tutorial I was able to migrate your Python implementation to C#. I am running mono on the Raspberry Pi and using RaspberryPi.Net library.
You can find his code here. From the software documentation:
The purpose of this library is to provide a Mono.NET interface to the GPIO pins on the Raspberry Pi. All of this code was written using Visual Studio 2010 Express but the goal is to be fully compatible with Mono. This library is written using .NET 4.0 therefore the latest version of Mono (2.10) is recommended. At the time of this update, the Raspbian wheezy 2012-07-15 image installs Mono 188.8.131.52.
The GPIO pins are best described here. They can be accessed in 2 ways, either using the file-based I/O (GPIOFile.cs) or direct memory (GPIOMem.cs) using Mike McCauley’s BCM2835 library which is available here. There is also a GPIODebug.cs class that can be used to test your application without a Raspberry Pi.
Here is a sample bit of code to blink an LED attached to pin 12
8-6-2021 (August 6, 2021) is the Snakiest day of the year and it’s also this year’s CircuitPython Day! The day highlights all things CircuitPython and Python on Hardware. See you there!
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.