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 procedurePublic Const WH_KEYBOARD_LL As Long = 13 'enables monitoring of keyboard 'input events about to be posted 'in a thread input queuePrivate Const HC_ACTION As Long = 0 'wParam and lParam parameters'contain information about a'keyboard messagePublic Const VK_CAPITAL As Long = &H14Public Const VK_NUMLOCK As Long = &H90Public Const VK_SCROLL As Long = &H91Private Const LLKHF_UP As Long = &H80& 'test the transition-state flagPublic Type KeyboardByteskbByte(0 To 255) As ByteEnd TypePrivate Type KBDLLHOOKSTRUCTvkCode As Long 'a virtual-key code in the range 1 to 254 scanCode As Long 'hardware scan code for the keyflags As Long 'specifies the extended-key flag,'event-injected flag, context code,'and transition-state flagtime As Long 'time stamp for this messagedwExtraInfo As Long 'extra info associated with the messageEnd TypePublic Declare Function SetWindowsHookEx Lib "user32" _Alias "SetWindowsHookExA" _(ByVal idHook As Long, _ByVal lpfn As Long, _ByVal hmod As Long, _ByVal dwThreadId As Long) As LongPublic Declare Function UnhookWindowsHookEx Lib "user32" _(ByVal hHook As Long) As LongPublic Declare Function CallNextHookEx Lib "user32" _(ByVal hHook As Long, _ByVal nCode As Long, _ByVal wParam As Long, _ByVal lParam As Long) As LongPublic 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 LongPublic Declare Function GetKeyState Lib "user32" _(ByVal nVirtKey As Long) As IntegerPublic Function LowLevelKeyboardProc(ByVal nCode As Long, _ByVal wParam As Long, _ByVal lParam As Long) As Long Dim kbdllhs As KBDLLHOOKSTRUCTIf nCode = HC_ACTION ThenCall CopyMemory(kbdllhs, ByVal lParam, Len(kbdllhs))If (kbdllhs.flags And LLKHF_UP) ThenSelect Case kbdllhs.vkCodeCase VK_NUMLOCKbel1.Visible = (GetKeyState(VK_NUMLOCK) = &HFF81)Case VK_CAPITALbel2.Visible = (GetKeyState(VK_CAPITAL) = &HFF81)Case VK_SCROLLbel3.Visible = (GetKeyState(VK_SCROLL) = &HFF81)Case ElseEnd SelectEnd IfEnd If 'nCode = HC_ACTIONLowLevelKeyboardProc = CallNextHookEx(m_hDllKbdHook, _nCode, _wParam, _lParam)End FunctionForm1中加入3个标签控件Label1、Label2、Label3Form1中的代码Private Sub Form_Load()Dim kbdState As KeyboardBytesCall GetKeyboardState(kbdState)With Label1.Caption = "Numlock is ON".Alignment = vbRightJustifyEnd WithWith Label2.Caption = "Caps lock is ON".Alignment = vbRightJustifyEnd WithWith Label3.Caption = "Scroll lock is ON".Alignment = vbRightJustifyEnd WithLabel1.Visible = kbdState.kbByte(VK_NUMLOCK) = 1Label2.Visible = kbdState.kbByte(VK_CAPITAL) = 1Label3.Visible = kbdState.kbByte(VK_SCROLL) = 1'set and obtain the handle to the keyboard hookm_hDllKbdHook = SetWindowsHookEx(WH_KEYBOARD_LL, _AddressOf LowLevelKeyboardProc, _ App.hInstance, _0&)If m_hDllKbdHook = 0 ThenMsgBox "Failed to install low-level keyboard hook."End IfEnd SubPrivate Sub Form_QueryUnload(Cancel As Integer, UnloadMode As Integer)If m_hDllKbdHook <> 0 ThenCall UnhookWindowsHookEx(m_hDllKbdHook)End IfEnd Sub'还有一段可以禁用Ctrl+Esc Alt + Esc Alt+Tab三组热键的Private Const WH_KEYBOARD_LL = 13& 'enables monitoring of keyboard 'input events about to be posted 'in a thread input queuePrivate Const HC_ACTION = 0& 'wParam and lParam parameters 'contain information about a'keyboard messagePrivate Const LLKHF_EXTENDED = &H1& 'test the extended-key flag Private Const LLKHF_INJECTED = &H10& 'test the event-injected flag Private Const LLKHF_ALTDOWN = &H20& 'test the context codePrivate Const LLKHF_UP = &H80& 'test the transition-state flag Private Const VK_TAB = &H9 'virtual key constantsPrivate Const VK_CONTROL = &H11Private Const VK_ESCAPE = &H1BPrivate Type KBDLLHOOKSTRUCTvkCode As Long 'a virtual-key code in the range 1 to 254 scanCode As Long 'hardware scan code for the keyflags As Long 'specifies the extended-key flag,'event-injected flag, context code,'and transition-state flagtime As Long 'time stamp for this messagedwExtraInfo As Long 'extra info associated with the messageEnd TypePrivate Declare Function SetWindowsHookEx Lib "user32" _Alias "SetWindowsHookExA" _(ByVal idHook As Long, _ByVal lpfn As Long, _ByVal hmod As Long, _ByVal dwThreadId As Long) As LongPrivate Declare Function UnhookWindowsHookEx Lib "user32" _(ByVal hHook As Long) As LongPrivate Declare Function CallNextHookEx Lib "user32" _(ByVal hHook As Long, _ByVal nCode As Long, _ByVal wParam As Long, _ByVal lParam As Long) As LongPrivate Declare Sub CopyMemory Lib "kernel32" _Alias "RtlMoveMemory" _(pDest As Any, _pSource As Any, _ByVal cb As Long)Private Declare Function GetAsyncKeyState Lib "user32" _(ByVal vKey As Long) As IntegerPrivate m_hDllKbdHook As Long 'private variable holding'the handle to the hook procedure Public Sub Main()'set and obtain the handle to the keyboard hookm_hDllKbdHook = SetWindowsHookEx(WH_KEYBOARD_LL, _AddressOf LowLevelKeyboardProc, _ App.hInstance, _0&)If m_hDllKbdHook <> 0 ThenMsgBox "Ctrl+Esc, Alt+Tab and Alt+Esc are blocked. " & _"Click OK to quit and re-enable the keys.", _vbOKOnly Or vbInformation, _"Keyboard Hook Active"Call UnhookWindowsHookEx(m_hDllKbdHook)ElseMsgBox "Failed to install low-level keyboard hook - " & stDllErrorEnd IfEnd SubPublic Function LowLevelKeyboardProc(ByVal nCode As Long, _ByVal wParam As Long, _ByVal lParam As Long) As LongStatic kbdllhs As KBDLLHOOKSTRUCTIf nCode = HC_ACTION ThenCall CopyMemory(kbdllhs, ByVal lParam, Len(kbdllhs))'Ctrl+Esc --------------If (kbdllhs.vkCode = VK_ESCAPE) And _CBool(GetAsyncKeyState(VK_CONTROL) _And &H8000) ThenDebug.Print "Ctrl+Esc blocked"LowLevelKeyboardProc = 1Exit FunctionEnd If 'kbdllhs.vkCode = VK_ESCAPE'Alt+Tab --------------If (kbdllhs.vkCode = VK_TAB) And _CBool(kbdllhs.flags And _LLKHF_ALTDOWN) ThenDebug.Print "Alt+Tab blocked"LowLevelKeyboardProc = 1Exit FunctionEnd If 'kbdllhs.vkCode = VK_TAB'Alt+Esc --------------If (kbdllhs.vkCode = VK_ESCAPE) And _CBool(kbdllhs.flags And _LLKHF_ALTDOWN) ThenDebug.Print "Alt+Esc blocked"LowLevelKeyboardProc = 1Exit FunctionEnd If 'kbdllhs.vkCode = VK_ESCAPEEnd If 'nCode = HC_ACTIONLowLevelKeyboardProc = CallNextHookEx(m_hDllKbdHook, _ nCode, _wParam, _lParam)End Function。