private void Callback(IntPtr midiInHandle, MidiInterop.MidiInMessage message, IntPtr userData, IntPtr messageParameter1, IntPtr messageParameter2)
{
switch (message)
{
case MidiInterop.MidiInMessage.Open:
// message Parameter 1 & 2 are not used
break;
case MidiInterop.MidiInMessage.Data:
// parameter 1 is packed MIDI message
// parameter 2 is milliseconds since MidiInStart
if (MessageReceived != null)
{
MessageReceived(this, new MidiInMessageEventArgs(messageParameter1.ToInt32(), messageParameter2.ToInt32()));
}
break;
case MidiInterop.MidiInMessage.Error:
// parameter 1 is invalid MIDI message
if (ErrorReceived != null)
{
ErrorReceived(this, new MidiInMessageEventArgs(messageParameter1.ToInt32(), messageParameter2.ToInt32()));
}
break;
case MidiInterop.MidiInMessage.Close:
// message Parameter 1 & 2 are not used
break;
case MidiInterop.MidiInMessage.LongData:
// parameter 1 is pointer to MIDI header
// parameter 2 is milliseconds since MidiInStart
if (SysexMessageReceived != null)
{
MidiInterop.MIDIHDR hdr = (MidiInterop.MIDIHDR)Marshal.PtrToStructure(messageParameter1, typeof(MidiInterop.MIDIHDR));
// Copy the bytes received into an array so that the buffer is immediately available for re-use
var sysexBytes = new byte[hdr.dwBytesRecorded];
Marshal.Copy(hdr.lpData, sysexBytes, 0, hdr.dwBytesRecorded);
SysexMessageReceived(this, new MidiInSysexMessageEventArgs(sysexBytes, messageParameter2.ToInt32()));
// Re-use the buffer - but not if we have no event handler registered as we are closing
MidiInterop.midiInAddBuffer(hMidiIn, messageParameter1, Marshal.SizeOf(typeof(MidiInterop.MIDIHDR)));
}
break;
case MidiInterop.MidiInMessage.LongError:
// parameter 1 is pointer to MIDI header
// parameter 2 is milliseconds since MidiInStart
break;
case MidiInterop.MidiInMessage.MoreData:
// parameter 1 is packed MIDI message
// parameter 2 is milliseconds since MidiInStart
break;
}
}
/// <summary>
/// Create a number of buffers and make them available to receive incoming Sysex messages
/// </summary>
/// <param name="bufferSize">The size of each buffer, ideally large enough to hold a complete message from the device</param>
/// <param name="numberOfBuffers">The number of buffers needed to handle incoming Midi while busy</param>
public void CreateSysexBuffers(int bufferSize, int numberOfBuffers)
{
SysexBufferHeaders = new IntPtr[numberOfBuffers];
var hdrSize = Marshal.SizeOf(typeof(MidiInterop.MIDIHDR));
for (var i = 0; i < numberOfBuffers; i++)
{
var hdr = new MidiInterop.MIDIHDR();
hdr.dwBufferLength = bufferSize;
hdr.dwBytesRecorded = 0;
hdr.lpData = Marshal.AllocHGlobal(bufferSize);
hdr.dwFlags = 0;
var lpHeader = Marshal.AllocHGlobal(hdrSize);
Marshal.StructureToPtr(hdr, lpHeader, false);
MmException.Try(MidiInterop.midiInPrepareHeader(hMidiIn, lpHeader, Marshal.SizeOf(typeof(MidiInterop.MIDIHDR))), "midiInPrepareHeader");
MmException.Try(MidiInterop.midiInAddBuffer(hMidiIn, lpHeader, Marshal.SizeOf(typeof(MidiInterop.MIDIHDR))), "midiInAddBuffer");
SysexBufferHeaders[i] = lpHeader;
}
}