A callback was made on a garbage collected delegate Error

I'm writing an application that uses USB interface....



I'm getting this error sometimes when i migrated from vb6 to vb2005 (migration required to reference process not by his address but by Delegate function)

A callback was made on a garbage collected delegate of type 'Project1!Project1.HIDDLLInterface+SubClassProcDelegate::Invoke'. This may cause application crashes, corruption and data loss. When passing delegates to unmanaged code, they must be kept alive by the managed application until it is guaranteed that they will never be called.

My code is below...I appreciate any help with this! thanks in advance!

Option Strict Off
Option Explicit On
Module HIDDLLInterface
' this is the interface to the HID controller DLL - you should not
' normally need to change anything in this file.
'
' WinProc() calls your main form 'event' procedures - these are currently
' set to..
'
' MainForm.OnPlugged(ByVal pHandle as long)
' MainForm.OnUnplugged(ByVal pHandle as long)
' MainForm.OnChanged()
' MainForm.OnRead(ByVal pHandle as long)
Delegate Function SubClassProcDelegate(ByVal hwnd As Integer, ByVal msg As Integer, ByVal wParam As Integer, ByVal lParam As Integer) As Integer
Declare Function SetWindowLong Lib "USER32.DLL" Alias "SetWindowLongA" (ByVal hwnd As Integer, ByVal attr As Integer, ByVal lVal As SubClassProcDelegate) As Integer

' HID interface API declarations...
Declare Function hidConnect Lib "mcHID.dll" Alias "Connect"(ByVal pHostWin As Integer) As Boolean
Declare Function hidDisconnect Lib "mcHID.dll" Alias "Disconnect"() As Boolean
Declare Function hidGetItem Lib "mcHID.dll" Alias "GetItem"(ByVal pIndex As Integer) As Integer
Declare Function hidGetItemCount Lib "mcHID.dll" Alias "GetItemCount"() As Integer
Declare Function hidRead Lib "mcHID.dll" Alias "Read"(ByVal pHandle As Integer, ByRef pData As Byte) As Boolean
Declare Function hidWrite Lib "mcHID.dll" Alias "Write"(ByVal pHandle As Integer, ByRef pData As Byte) As Boolean
Declare Function hidReadEx Lib "mcHID.dll" Alias "ReadEx"(ByVal pVendorID As Integer, ByVal pProductID As Integer, ByRef pData As Byte) As Boolean
Declare Function hidWriteEx Lib "mcHID.dll" Alias "WriteEx"(ByVal pVendorID As Integer, ByVal pProductID As Integer, ByRef pData As Byte) As Boolean
Declare Function hidGetHandle Lib "mcHID.dll" Alias "GetHandle"(ByVal pVendoID As Integer, ByVal pProductID As Integer) As Integer
Declare Function hidGetVendorID Lib "mcHID.dll" Alias "GetVendorID"(ByVal pHandle As Integer) As Integer
Declare Function hidGetProductID Lib "mcHID.dll" Alias "GetProductID"(ByVal pHandle As Integer) As Integer
Declare Function hidGetVersion Lib "mcHID.dll" Alias "GetVersion"(ByVal pHandle As Integer) As Integer
Declare Function hidGetVendorName Lib "mcHID.dll" Alias "GetVendorName"(ByVal pHandle As Integer, ByVal pText As String, ByVal pLen As Integer) As Integer
Declare Function hidGetProductName Lib "mcHID.dll" Alias "GetProductName"(ByVal pHandle As Integer, ByVal pText As String, ByVal pLen As Integer) As Integer
Declare Function hidGetSerialNumber Lib "mcHID.dll" Alias "GetSerialNumber"(ByVal pHandle As Integer, ByVal pText As String, ByVal pLen As Integer) As Integer
Declare Function hidGetInputReportLength Lib "mcHID.dll" Alias "GetInputReportLength"(ByVal pHandle As Integer) As Integer
Declare Function hidGetOutputReportLength Lib "mcHID.dll" Alias "GetOutputReportLength"(ByVal pHandle As Integer) As Integer
Declare Sub hidSetReadNotify Lib "mcHID.dll" Alias "SetReadNotify"(ByVal pHandle As Integer, ByVal pValue As Boolean)
Declare Function hidIsReadNotifyEnabled Lib "mcHID.dll" Alias "IsReadNotifyEnabled"(ByVal pHandle As Integer) As Boolean
Declare Function hidIsAvailable Lib "mcHID.dll" Alias "IsAvailable"(ByVal pVendorID As Integer, ByVal pProductID As Integer) As Boolean

' windows API declarations - used to set up messaging...
Private Declare Function CallWindowProc Lib "user32" Alias "CallWindowProcA"(ByVal lpPrevWndFunc As Integer, ByVal hwnd As Integer, ByVal Msg As Integer, ByVal wParam As Integer, ByVal lParam As Integer) As Integer
Private Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA"(ByVal hwnd As Integer, ByVal nIndex As Integer, ByVal dwNewLong As Integer) As Integer

' windows API Constants
Private Const WM_APP As Integer = 32768
Private Const GWL_WNDPROC As Short = -4

' HID message constants
Private Const WM_HID_EVENT As Decimal = WM_APP + 200
Private Const NOTIFY_PLUGGED As Short = 1
Private Const NOTIFY_UNPLUGGED As Short = 2
Private Const NOTIFY_CHANGED As Short = 3
Private Const NOTIFY_READ As Short = 4

' local variables
Private FPrevWinProc As Integer ' Handle to previous window procedure
Private FWinHandle As Integer ' Handle to message window

' Set up a windows hook to receive notification
' messages from the HID controller DLL - then connect
' to the controller
' Delegate Function SubClassProcDelegate(ByVal hwnd As Integer, ByVal msg As Integer, ByVal wParam As Integer, ByVal lParam As Integer) As Integer

Public Function ConnectToHID(ByVal pHostWin As Integer) As Boolean
FWinHandle = pHostWin
ConnectToHID = hidConnect(FWinHandle)
'UPGRADE_WARNING: Add a delegate for AddressOf WinProc Click for more: 'ms-help://MS.VSExpressCC.v80/dv_commoner/local/redirect.htm?keyword="E9E157F7-EF0C-4016-87B7-7D7FBBC6EE08"'
FPrevWinProc = SetWindowLong(FWinHandle, GWL_WNDPROC, AddressOf WinProc)
End Function

' Unhook from the HID controller and disconnect...
Public Function DisconnectFromHID() As Boolean
DisconnectFromHID = hidDisconnect
SetWindowLong(FWinHandle, GWL_WNDPROC, FPrevWinProc)
End Function

' This is the procedure that intercepts the HID controller messages...


Private Function WinProc(ByVal pHWnd As Integer, ByVal pMsg As Integer, ByVal wParam As Integer, ByVal lParam As Integer) As Integer
If pMsg = WM_HID_EVENT Then
Select Case wParam

' HID device has been plugged message...
Case Is = NOTIFY_PLUGGED
MainForm.OnPlugged((lParam))

' HID device has been unplugged
Case Is = NOTIFY_UNPLUGGED
MainForm.OnUnplugged((lParam))

' controller has changed...
Case Is = NOTIFY_CHANGED
MainForm.OnChanged()

' read event...
Case Is = NOTIFY_READ
MainForm.OnRead((lParam))
End Select

End If

' next...
WinProc = CallWindowProc(FPrevWinProc, pHWnd, pMsg, wParam, lParam)

End Function
End Module