用VB实现的全局键盘钩子
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用VB实现的全局键盘钩子
2010-04-06 13:30
代码功能：实时监测Caps Lock、NumLock、Scroll Lock三个按件的状态，并显示在Label1 Label2 Label3三个标签中
'.bas模块中
Public m_hDllKbdHook As Long 'public variable holding
'the handle to the hook procedure
Public Const WH_KEYBOARD_LL As Long = 13 'enables monitoring of keyboard 'input events about to be posted 'in a thread input queue
Private Const HC_ACTION As Long = 0 'wParam and lParam parameters
'contain information about a
'keyboard message
Public Const VK_CAPITAL As Long = &H14
Public Const VK_NUMLOCK As Long = &H90
Public Const VK_SCROLL As Long = &H91
Private Const LLKHF_UP As Long = &H80& 'test the transition-state flag
Public Type KeyboardBytes
kbByte(0 To 255) As Byte
End Type
Private Type KBDLLHOOKSTRUCT
vkCode As Long 'a virtual-key code in the range 1 to 254 scanCode As Long 'hardware scan code for the key
flags As Long 'specifies the extended-key flag,
'event-injected flag, context code,
'and transition-state flag
time As Long 'time stamp for this message
dwExtraInfo As Long 'extra info associated with the message
End Type
Public Declare Function SetWindowsHookEx Lib "user32" _
Alias "SetWindowsHookExA" _
(ByVal idHook As Long, _
ByVal lpfn As Long, _
ByVal hmod As Long, _
ByVal dwThreadId As Long) As Long
Public Declare Function UnhookWindowsHookEx Lib "user32" _
(ByVal hHook As Long) As Long
Public Declare Function CallNextHookEx Lib "user32" _
(ByVal hHook As Long, _
ByVal nCode As Long, _
ByVal wParam As Long, _
ByVal lParam As Long) As Long
Public Declare Sub CopyMemory Lib "kernel32" _
Alias "RtlMoveMemory" _
(pDest As Any, _
pSource As Any, _
ByVal cb As Long)
Public Declare Function GetKeyboardState Lib "user32" _
(kbArray As KeyboardBytes) As Long
Public Declare Function GetKeyState Lib "user32" _
(ByVal nVirtKey As Long) As Integer
Public Function LowLevelKeyboardProc(ByVal nCode As Long, _
ByVal wParam As Long, _
ByVal lParam As Long) As Long Dim kbdllhs As KBDLLHOOKSTRUCT
If nCode = HC_ACTION Then
Call CopyMemory(kbdllhs, ByVal lParam, Len(kbdllhs))
If (kbdllhs.flags And LLKHF_UP) Then
Select Case kbdllhs.vkCode
Case VK_NUMLOCK
bel1.Visible = (GetKeyState(VK_NUMLOCK) = &HFF81)
Case VK_CAPITAL
bel2.Visible = (GetKeyState(VK_CAPITAL) = &HFF81)
Case VK_SCROLL
bel3.Visible = (GetKeyState(VK_SCROLL) = &HFF81)
Case Else
End Select
End If
End If 'nCode = HC_ACTION
LowLevelKeyboardProc = CallNextHookEx(m_hDllKbdHook, _
nCode, _
wParam, _
lParam)
End Function
Form1中加入3个标签控件Label1、Label2、Label3
Form1中的代码
Private Sub Form_Load()
Dim kbdState As KeyboardBytes
Call GetKeyboardState(kbdState)
With Label1
.Caption = "Numlock is ON"
.Alignment = vbRightJustify
End With
With Label2
.Caption = "Caps lock is ON"
.Alignment = vbRightJustify
End With
With Label3
.Caption = "Scroll lock is ON"
.Alignment = vbRightJustify
End With
Label1.Visible = kbdState.kbByte(VK_NUMLOCK) = 1
Label2.Visible = kbdState.kbByte(VK_CAPITAL) = 1
Label3.Visible = kbdState.kbByte(VK_SCROLL) = 1