I have an Excel user form with a button that plays a wav file using
mciSendString. I am trying to make use of the notify parameter so I can take
some action when the file is done playing, but I can't get it to work. Here
is my relevant code:

Call mciSendString("play WavFile notify", 0, 0, AddressOf mciSendStringProc)

This is supposed to send the notify message to a procedure called
mciSendStringProc (located in a module). Here is the code for that:

Public Function mciSendStringProc(ByVal hWnd As Long, ByVal uMsg As Long,
ByVal wParam As Long, ByVal lParam As Long) As Long

MsgBox uMsg & wParam & lParam

mciSendStringProc = True

End Function

The wav file plays successfully, but I cannot get anything to happen when
it's finished.