sendmessage not working for jetaudio in vb6 - vb6

Question

i am trying to implement the Jetaudio API in vb6...
i have taken the values of the constants from the API SDK..
Private Declare Function FindWindow Lib "user32.dll" Alias "FindWindowA" ( _
ByVal lpClassName As String, _
ByVal lpWindowName As String) As Long
Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
Private Declare Function RegisterWindowMessage _
Lib "user32" Alias "RegisterWindowMessageA" _
(ByVal lpString As String) As Long
Public Const WM_APP As Long = &H8000
Public Const MyMSG As Long = WM_APP + 740
Public Function GetJetAudioSong()
Dim v As Long
Dim JAhwnd As Long
Dim lngMyMsg As Long
lngMyMsg = RegisterWindowMessage(MyMSG)
JAhwnd = FindWindow("COWON Jet-Audio Remocon Class", "Jet-Audio Remote Control")
v = SendMessage(JAhwnd, lngMyMsg, 0, 995)
MsgBox v
End Function
Now, FindWindow() is working cause JAhwnd is set with a value...
its just the sendmessage() that doesn't seem to be working...
the code is suppose to msgbox the version number for the running Jet Audio instance.
i've been at it for days now and i have no way of making sure weather this error is a VB thing or not... i am taking Jet Audio's SDK's word that the values of the const are correct...
the value of v is always 0 where it should be 6 on my system.
what am i doing wrong?

Answer 1

Don't call RegisterWindowMessage, MyMSG is message number that you should send to the Jet-Audio window.
Private Declare Function FindWindow Lib "user32.dll" Alias "FindWindowA" ( _
ByVal lpClassName As String, _
ByVal lpWindowName As String) As Long
Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
Public Const WM_APP As Long = &H8000
Public Const MyMSG As Long = WM_APP + 740
Public Function GetJetAudioSong()
Dim v As Long
Dim JAhwnd As Long
Dim lngMyMsg As Long
JAhwnd = FindWindow("COWON Jet-Audio Remocon Class", "Jet-Audio Remote Control")
v = SendMessage(JAhwnd, MyMSG, 0, 995)
MsgBox v
End Function

Answer 2

What Windows Version?
SendMessage and SendKeys no longer works with VB6 code starting at Windows Vista and above.
Do a Google search for it.

Answer 3

I know this is 2 years too late. Please use this as a future reference for anyone reading this in the future.
The fix for your issue is this:
'[ Use 'ByVal' for your lParam to make sure you are passing the actual value not the Reference
v = SendMessage(JAhwnd, lngMyMsg, 0, ByVal 995)
'[ Or you could perform PostMessage(..) and not use ByVal
v = PostMessage(JAhwnd, lngMyMsg, 0, 995)
Also, i HIGHLY recommend against anyone using SendKeys. API is the correct method to ensure you are sending message to the correct hWnd. I would suggest using SendKeys only if in desperation; it can happen.