public hotkey for vb

Option Explicit
Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" _
(ByVal hwnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long
Declare Function GetWindowLong Lib "user32" Alias "GetWindowLongA" _
(ByVal hwnd As Long, ByVal nIndex 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 Function RegisterHotKey Lib "user32" (ByVal hwnd As Long, ByVal id As Long, ByVal fsModifiers As Long, ByVal vk As Long) As Long
Declare Function UnregisterHotKey Lib "user32" (ByVal hwnd As Long, ByVal id As Long) As Long

Public Const WM_HOTKEY = &H312
Public Const MOD_ALT = &H1
Public Const MOD_CONTROL = &H2
Public Const MOD_SHIFT = &H4
Public Const GWL_WNDPROC = (-4)

Public preWinProc As Long
Public Modifiers As Long, uVirtKey As Long, idHotKey As Long

Private Type taLong
ll As Long
End Type

Private Type t2Int
lWord As Integer
hword As Integer
End Type

Public Function wndproc(ByVal hwnd As Long, ByVal Msg As Long, _
ByVal wParam As Long, ByVal lParam As Long) As Long
Dim lp As taLong, i2 As t2Int
If Msg = WM_HOTKEY Then
If wParam = idHotKey Then
lp.ll = lParam
LSet i2 = lp
If (i2.lWord = Modifiers) And i2.hword = uVirtKey Then
'加入自己的代码
Debug.Print "HotKey Shift-Alt-A Pressed "
Form1.Show
End If
End If
End If
'将之送往原来的Window Procedure
wndproc = CallWindowProc(preWinProc, hwnd, Msg, wParam, lParam)
End Function
'以下在 Form
Sub Form_Load()
Dim ret As Long
preWinProc = GetWindowLong(Me.hwnd, GWL_WNDPROC)
ret = SetWindowLong(Me.hwnd, GWL_WNDPROC, AddressOf wndproc)
idHotKey = 1 'in the range &h0000 through &hBFFF
Modifiers = MOD_ALT + MOD_SHIFT
uVirtKey = vbKeyA
ret = RegisterHotKey(Me.hwnd, idHotKey, Modifiers, uVirtKey)
End Sub

Private Sub Form_Unload(Cancel As Integer)
Dim ret As Long
'取消Message的截取，而使之又只送往原来的Window Procedure
ret = SetWindowLong(Me.hwnd, GWL_WNDPROC, preWinProc)
Call UnregisterHotKey(Me.hwnd, uVirtKey)
End Sub