ChannelAddWindow always gives me a result of Zero
Dim bs As New System.IntPtr(Form1.pb1.Handle.ToInt32) --the handle for the main form with preview picturebox on first monitor
Dim bsFullScreen As New System.IntPtr(FullScreen.pb1.Handle.ToInt32) --the handle for the fullscreen form with full picturebox on second monitor
Dim a As Integer
StreamHandle = BassDShow.BASS_DSHOW_StreamCreateFile(filename, 0, bs, BASSFlag.BASS_DEFAULT) --stream creates perfect and works on first monitor
a = BassDShow.BASS_DSHOW_ChannelAddWindow(StreamHandle, bsFullScreen) --a gives zero, so no output on second screen
what's wrong?

I do it like this (In .NET):
'in the Form_Load event:
BassDShow.BASS_DSHOW_Init(FrmMain.preview.Handle, AddOn.DShow.BASSDSHOWInit.BASS_DSHOW_Default)
..And when I create a stream:
STREAM1 = BASS_StreamCreateFile(videofile, 0, 0, OUTPUT)
BassDShow.BASS_DSHOW_ChannelAddWindow(STREAM1, frmVideo.Stream1Video.Handle)
So in my case the preview window is set-up in the INIT, and the output video on the second monitor is added when creating the stream.