Declare Function UnhookWindowsHookEx Lib "user32" _
(ByVal hHook As Long) As Long
Declare Function CallNextHookEx Lib "user32" (ByVal hHook As Long, _
ByVal nCode As Long, ByVal wParam As Long, lParam As Any) As Long
Declare Sub CopyMemory Lib "KERNEL32" Alias "RtlMoveMemory" _
(lpvDest As Any, ByVal lpvSource As Long, ByVal cbCopy As Long)
Public hNxtHook As Long ' handle of Hook Procedure
Public msg As EVENTMSG
Sub EnableHook()
hNxtHook = SetWindowsHookEx(0, AddressOf HookProc, App.hInstance, 0)
End Sub
Sub FreeHook()
Dim ret As Long
ret = UnhookWindowsHookEx(hNxtHook)
End Sub
Function HookProc(ByVal code As Long, ByVal wParam As Long, _
ByVal lParam As Long) As Long
CopyMemory msg, lParam, Lenb(msg)
If (msg.message >= WM_KEYFIRST _
And msg.message <= WM_KEYLAST) Then
Debug.Print msg.message, msg.paramH
End If
HookProc = CallNextHookEx(hNxtHook, code, wParam, lParam)
End Function
'以下程式於Form1
Private Sub Form_Load()
Call EnableHook
End Sub
Private Sub Form_Unload(Cancel As Integer)
Call FreeHook
End Sub
*****************************************************************************
详细的流程不多做说明，我们只把重点放在HookProc这个Hook Procedure，如果我
们查JournalRecord Hook的Hook Procedure可得定义如下：
-----------------------------------------------------------------------------
LRESULT CALLBACK JournalRecordProc(
int code, // hook code
WPARAM wParam, // undefined
LPARAM lParam // 为一个EVENTMSG Structure的address值
);
这个JournalRecordProc 对应到我们的HookProc便是
Function HookProc(ByVal code As Long, ByVal wParam As Long, _
ByVal lParam As Long) As Long
-----------------------------------------------------------------------------
有没有注意到第三个叁数它是一个 ByVal的Long，指的是存放某一个EVENTMSG的位址，
而先前我们提过，自定型态的叁数传递要使用ByRef的方式才能解决，天啊！它用ByVal
的方式来做，如果是C语言，那不成问题，只要如下：
-----------------------------------------------------------------------------
EVENTMSG *p;
P = (EVENTMSG *) lParam;
-----------------------------------------------------------------------------
如此便可以用 *p->message 之方式来取得内容，但VB呢？这里便要用些小技巧了，试
想，如果我们能依lParam所指的位址，一个Byte一个Byte的Copy到一个EVENTMSG的变数
上面，不就可以了吗？所以了， CopyMomory这个函式派上用场了，但是 CopyMomory上一页 [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] 下一页
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