Requirements

[mkoch44]

Under "Requirements" is written:
-- .NET Framework 3.5
-- Visual Studio C# 2008 or later

I tested with .NET 4.5 and Visual Studio 2013 and it's impossible to install this project. It seems at least .NET 4.7 is required. I gave up at this point.

[micdah]

That's a good point, haven't updated requirements based on updating to .Net 4.7 diverting from upstream.

You might also be interested in https://github.com/micdah/RtMidi.Core which is for netstandard2.0 and uses rtmidi as backend enabling usage on windows and macosx (and linux in theory, although I have not worked on supporting this)

[jstnryan]

@mkoch44, if this is a blocker for you, you can try to compile my upstream branch: https://github.com/jstnryan/midi-dot-net
It is where the .NET 3.5 requirement comes from, and should compile in later versions with minimal changes. However this will not include whatever changes @micdah has made to his fork.