List of Free code MIDI

BYOND - Build Your OwN Device (audio synths, effects, DSP, sequencer, VST)
Byond is an environment for audio and midi programming in C#. It's available as VST plugin or standalone application.
MIDI File Mapper
MIDI File Mapper is a utility that is designed to batch convert MIDI files from one note mapping to another. This is particularly useful when using libraries of drum patterns mapped for a particular drum sampler with a different sampler.
MIDI File Splitter
MIDI File Splitter is a simple utility designed to split a MIDI file up into multiple sections based on its markers. It was originally designed to be used for splitting up the Session Drummer and Pattern Brush MIDI files included with Cakewalk's SONAR into individual patterns ...
MIDI.NET
MIDI.NET allows any .NET developer to access the power of MIDI without (the developer) having to do P/Invokes.
NAudio
A .NET library for writing audio related Windows applications. In particular, it provides access to playback and record audio, as well as support for various audio file types such as Standard MIDI files and Soundfonts.
Pure Midi
Pure Midi - Handling midi communication in .NET with full sequencing support and arranger like musical styles playing.
WinRTP-MIDI
A portable implementation of the RTP-MIDI network protocol.