GetAsyncKeyState()=========================
功能：确定用户当前是否按下了键盘上的一个键
原型：SHORT GetAsyncKeyState(int vKey);

参数：nVirtKey指出要检查键的虚键代码。结果的高位指出该键当前是否被按下（是为1，否为0）。
常用键的VK值：
VK_SHIFT Shift键
VK_LSHIFT 左Shift键
VK_RSHIFT 右Shift键
VK_CONTROL Ctrl键
VK_LCONTROL 左Ctrl键
VK_RCONTROL 右Ctril键
VK_MENU Alt键
VK_LMENU 左Alt键
VK_RMENU 右Alt键
VK_LBUTTON 鼠标左键
VK_RBUTTON 鼠标右键

另一个函数GetKeyState与GetAsyncKeyState函数不同。GetAsyncKeyState在按下某键的同时调用，判断正在按下某键。
GetKeyState则在按过某键之后再调用，它返回最近的键盘消息从线程的队列中移出时的键盘状态，判断刚按过了某键。

与RegisterHotKey()相比，GetAsyncKeyState()的优点在于可以监控鼠标按键，缺点是需要使用定时器，并且无法保证热键的惟一性。

;<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
; 文件名: HotKey2.asm
; 作　者: Purple Endurer
; 功　能: 演示定时器SetTimer()和GetAsyncKeyState()
; 点击“监测Alt+鼠标右键! 成功后按
; Alt+鼠标右键可打开记事本!”按钮，
; 则尝试监测Alt+鼠标右键是否按下
; 如果尝试不成功，则提示出错信息！
; 如果尝试成功，则按Alt+鼠标右键时，
; 可将当前程序窗口恢复到前台
; 并启动计事本！
; 开发环境:Windows 2000 Pro + MASM32
; 注：源代码和可执行程序可以到http://下载
;
; Date log
;-------------------------------------------------
;2006-03-09 创建！
;<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

.386
.model flat, stdcall
option casemap: none
include /masm32/ include/windows.inc
include /masm32/ include/user32.inc
include /masm32/ include/kernel32.inc
include /masm32/ include/shell32.inc
includelib /masm32/ lib/user32.lib
includelib /masm32/ lib/kernel32.lib
includelib /masm32/ lib/shell32.lib

WinMain proto : DWORD, : DWORD, : DWORD, : DWORD

m_m2m MACRO d1, d2
push d2
pop d1
ENDM


.const
c_ButtonID equ 1
c_TimerID equ 1

.data
g_szWinClsName db "DemoWinClass", 0
g_szAppName db "系统演示程序2 by PurpleEndurer", 0
g_szBtnClsName db "button", 0
g_szFailSetTimer db "不能"
g_szRegisterKey db "监测Alt+鼠标右键! 成功后按Alt+鼠标右键可打开记事本!", 0
g_szFailKillTimer db "不能"
g_szUnregisterKey db "停止监测Alt+鼠标右键!", 0
g_bRegisted dword FALSE
g_szOpen db "Open", 0
g_szNotePad db "NotePad", 0

.data?
hInstance HINSTANCE ?
CommandLine LPSTR ?
g_hwndButton HANDLE ?

.code
start:
invoke GetModuleHandle, NULL
mov hInstance, eax
invoke GetCommandLine
mov CommandLine, eax
invoke WinMain, hInstance, NULL, CommandLine, SW_SHOWDEFAULT
invoke ExitProcess, eax
WinMain proc hInst:HINSTANCE, hPrevInst:HINSTANCE, CmdLine:LPSTR, CmdShow: DWORD
LOCAL wc:WNDCLASSEX
LOCAL msg:MSG
LOCAL hwnd:HWND
mov wc.cbSize, SIZEOF WNDCLASSEX
mov wc.style, CS_HREDRAW or CS_VREDRAW
mov wc.lpfnWndProc, OFFSET WndProc
mov wc.cbClsExtra, NULL
mov wc.cbWndExtra, NULL
push hInstance
pop wc.hInstance
mov wc.hbrBackground, COLOR_WINDOW+1
mov wc.lpszMenuName, NULL
mov wc.lpszClassName, OFFSET g_szWinClsName
invoke LoadIcon, NULL, IDI_APPLICATION
mov wc.hIcon, eax
mov wc.hIconSm, eax
invoke LoadCursor, NULL, IDC_ARROW
mov wc.hCursor, eax
invoke RegisterClassEx, addr wc
INVOKE CreateWindowEx, NULL, ADDR g_szWinClsName, ADDR g_szAppName, /
WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, /
CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, NULL, NULL, /
hInst, NULL
mov hwnd, eax
invoke ShowWindow, hwnd, SW_SHOWNORMAL
invoke UpdateWindow, hwnd
.WHILE TRUE
invoke GetMessage, ADDR msg, NULL, 0, 0
.BREAK .IF (! eax)
invoke TranslateMessage, ADDR msg
invoke DispatchMessage, ADDR msg
.ENDW
mov eax, msg.wParam
ret
WinMain endp

WndProc proc hWnd:HWND, uMsg:UINT, wParam:WPARAM, lParam:LPARAM
.IF uMsg==WM_DESTROY
.if g_bRegisted== TRUE
invoke KillTimer, hWnd, c_TimerID
.endif
invoke PostQuitMessage, NULL
.ELSEIF uMsg==WM_CREATE
;创建按钮
invoke CreateWindowEx, NULL, ADDR g_szBtnClsName, ADDR g_szRegisterKey, /
WS_CHILD or WS_VISIBLE or BS_DEFPUSHBUTTON,/
25, 25, 560, 50, hWnd, c_ButtonID, hInstance, NULL
mov g_hwndButton, eax

.ELSEIF uMsg==WM_COMMAND
mov eax, wParam
.IF lParam!=0
.IF ax==c_ButtonID
shr eax, 16
.IF ax==BN_CLICKED
.if g_bRegisted== TRUE
;禁用监测
invoke KillTimer, hWnd, c_TimerID
.IF eax==0
invoke MessageBox, hWnd, ADDR g_szFailKillTimer,/
ADDR g_szAppName, MB_IC ONERROR
ret
.ENDIF

m_m2m g_bRegisted, FALSE
;修改按钮的文本
invoke SetWindowText, g_hwndButton, ADDR g_szRegisterKey
.else
;启用监测
invoke SetTimer, hWnd, c_TimerID, 100, NULL

.IF eax==0
invoke MessageBox, hWnd, ADDR g_szFailSetTimer,/
ADDR g_szAppName, MB_IC ONERROR
ret
.ENDIF
m_m2m g_bRegisted, TRUE
;修改按钮的文本
invoke SetWindowText, g_hwndButton, ADDR g_szUnregisterKey
.endif
.ENDIF
.ENDIF
.ENDIF
.ELSEIF uMsg==WM_TIMER
invoke GetAsyncKeyState, VK_LMENU ;左Alt键
test eax, 08000h
jz @F
invoke GetAsyncKeyState, VK_RBUTTON ;鼠标右键
test eax, 08000h
jz @F
;把本程序窗口恢复到前台
invoke ShowWindow, hWnd, SW_RESTORE
invoke SetForegroundWindow, hWnd

;打开记事本
invoke ShellExecute, hWnd, ADDR g_szOpen, ADDR g_szNotePad, NULL, NULL, SW_RESTORE
@@:
.ELSE
invoke DefWindowProc, hWnd, uMsg, wParam, lParam
ret
.ENDIF
xor eax, eax
ret
WndProc endp

end