I have a KKMoon ACR122U-A9 reader and have downloaded the latest required drivers for it. I'm using Sierra 10.12.2 and can connect to the reader using the pcsctest terminal command. However after hours of research, I still can't find a way of reading/writing data to cards using the .NET framework on Mac. Almost all examples I found were Windows based. I have tried the pcsc-sharp Nuget package, with some success, but it only fully supports Windows and Unix.
Am I going to have to run Windows in order to create a .NET program to communicate with the reader? Or is there a Mac library that can help me?
I don't think using .NET framework on OS X is a good idea. If .NET is not a requirement, you can use Java.
You can find grundig nfctools library to develop NFC applications with Java support.
You can find also grundig nfctools-examples that are developed using an ACR122U that should facilitate your work