Attribute VB_Name = "Subclass"
Option Explicit

Public Const WM_USER = &H400

Public Const GWL_WNDPROC = (-4)
Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" _
    (ByVal hwnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long
Declare Function CallWindowProc Lib "user32" Alias "CallWindowProcA" _
    (ByVal lpPrevWndFunc As Long, ByVal hwnd As Long, ByVal msg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" _
      (hpvDest As Any, hpvSource As Any, ByVal cbCopy As Long)

Public origWndProc As Long
Public Sub SetHook(hwnd, bSet As Boolean)
    
    If bSet Then
        origWndProc = SetWindowLong(hwnd, GWL_WNDPROC, AddressOf AppWndProc)
    ElseIf origWndProc Then
        Dim lRet As Long
        lRet = SetWindowLong(hwnd, GWL_WNDPROC, origWndProc)
    End If

End Sub
Public Function AppWndProc(ByVal hwnd As Long, ByVal msg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
    
    Select Case msg
        Case WM_USER + 1
            Select Case LoWord(lParam)
                Case FD_READ
                    Form1.VbRecv hwnd, msg, wParam, lParam
                Case FD_CLOSE
                    Form1.VbClose hwnd, msg, wParam, lParam
                Case FD_ACCEPT
                    Form1.VbAccept hwnd, msg, wParam, lParam
            End Select
    End Select
    AppWndProc = CallWindowProc(origWndProc, hwnd, msg, wParam, lParam)

End Function
Public Function LoWord(ByVal LongIn As Long) As Integer
   
   Call CopyMemory(LoWord, LongIn, 2)

End Function
Public Function HiWord(ByVal LongIn As Long) As Integer
   
   Call CopyMemory(HiWord, ByVal (VarPtr(LongIn) + 2), 2)

End Function