『windows』WM_HOTKEY 热键

1. WM_HOTKEY

This message is posted when the user presses a hot key registered by the RegisterHotKey function. The message is placed at the top of the message queue associated with the thread that registered the hot key.

WM_HOTKEY idHotKey = (int) wParam; 
  fuModifiers = (UINT) LOWORD(lParam); 
  uVirtKey = (UINT) HIWORD(lParam);

Parameters

idHotKey

Hot key identifier that generated the message. If the message was generated by a system-defined hot key, the idHotKey parameter is one of the following values.

Value	Description
IDHOT_SNAPDESKTOP	The snap desktop hot key was pressed.
IDHOT_SNAPWINDOW	The snap window hot key was pressed.

fuModifiers

Specifies the keys that were to be pressed in combination with the key specified by the nVirtKey parameter to generate the WM_HOTKEY message. The fuModifiers parameter can be a combination of the following values.

Value	Description
MOD_ALT	Either ALT key was held down.
MOD_CONTROL	Either CTRL key was held down.
MOD_KEYUP	Both key up events and key down events generate a WM_HOTKEY message
MOD_SHIFT	Either SHIFT key was held down.
MOD_WIN	Either WINDOWS key was held down. These keys are labeled with the Microsoft Windows logo.

uVirtKey

Specifies the virtual key code of the hot key. 

2. Keyboard Messages

Programming element	Description
WM_ACTIVATE	This message is sent when a window is being activated or deactivated.
WM_CHAR	This message is posted to the window with the keyboard focus when a WM_KEYDOWN message is translated by the TranslateMessage function.
WM_HOTKEY	This message is posted when the user presses a hot key registered by the RegisterHotKey function.
WM_INITMENUPOPUP	This message is sent when a pop-up menu is about to become active.
WM_KEYDOWN	This message is posted to the window with the keyboard focus when a nonsystem key is pressed.
WM_KEYUP	This message is posted to the window with the keyboard focus when a nonsystem key is released.
WM_KILLFOCUS	This message is sent to a window immediately before it loses the keyboard focus.
WM_MENUCHAR	This message is sent when a menu is active and the user presses a key that does not correspond to any mnemonic or accelerator key.
WM_SETFOCUS	This message is sent to a window after it has gained the keyboard focus.
WM_SYSCHAR	This message is posted to the window with the keyboard focus when a WM_SYSKEYDOWN message is translated by the TranslateMessage function.
WM_SYSCOMMAND	This message is sent to a window when the user chooses a command from the window menu, formerly known as the system or control menu, or when the user chooses the maximize button or the minimize button.
WM_SYSDEADCHAR	This message is posted to the window with the keyboard focus when a WM_SYSKEYDOWN message is translated by the TranslateMessage function.
WM_SYSKEYDOWN	This message is posted to the window with the keyboard focus when the user holds down the ALT key and then presses another key.
WM_SYSKEYUP	This message is posted to the window with the keyboard focus when the user releases a key that was pressed while the ALT key was held down.

3. RegisterHotKey

This function defines a system-wide hot key.

BOOL RegisterHotKey( 
  HWND hWnd, 
  int id, 
  UINT fsModifiers, 
  UINT vk 
);

Parameters

hWnd

[in] Handle to the window that will receive WM_HOTKEY messages generated by the hot key. The value of this parameter should not be NULL.

id

[in] Identifier of the hot key. No other hot key in the calling thread should have the same identifier. An application must specify a value in the range 0x0000 through 0xBFFF. A shared dynamic-link library (DLL) must specify a value in the range 0xC000 through 0xFFFF.

fsModifiers

[in] Specifies keys that must be pressed in combination with the key specified by the nVirtKey parameter in order to generate a WM_HOTKEY message. The fsModifiers parameter can be a combination of the following values.

Value	Description
MOD_ALT	Either ALT key must be held down.
MOD_CONTROL	Either CTRL key must be held down.
MOD_KEYUP	Both key up events and key down events generate a WM_HOTKEY message.
MOD_SHIFT	Either SHIFT key must be held down.
MOD_WIN	Either WINDOWS key was held down. These keys are labeled with the Microsoft Windows logo.

vk

[in] Specifies the virtual-key code of the hot key.

Return Values

Nonzero indicates success. Zero indicates failure. 

Remarks

When a key is pressed, the system looks for a match against all hot keys. Upon finding a match, the system posts the WM_HOTKEY message to the message queue of the thread that registered the hot key. This message is posted to the beginning of the queue so it is removed by the next iteration of the message loop.

RegisterHotKey can be used to register hot keys across threads.

RegisterHotKey fails if the keystrokes specified for the hot key have already been registered by another hot key.

If the window identified by the hWnd parameter already registered a hot key with the same identifier as that specified by the id parameter, the new values for the fsModifiers and vk parameters replace the previously specified values for these parameters. 

4. Virtual-Key Codes

Symbolic constant	Hexadecimal value	Mouse or keyboard equivalent
VK_LBUTTON	01	Left mouse button
VK_RBUTTON	02	Right mouse button
VK_CANCEL	03	Control-break processing
VK_MBUTTON	04	Middle mouse button on a three-button mouse
	0507	Undefined
VK_BACK	08	BACKSPACE key
VK_TAB	09	TAB key
	0A0B	Undefined
VK_CLEAR	0C	CLEAR key
VK_RETURN	0D	ENTER key
	0E0F	Undefined
VK_SHIFT	10	SHIFT key
VK_CONTROL	11	CTRL key
VK_MENU	12	ALT key
VK_PAUSE	13	PAUSE key
VK_CAPITAL	14	CAPS LOCK key
	1519	Reserved for Kanji systems
	1A	Undefined
VK_ESCAPE	1B	ESC key
	1C1F	Reserved for Kanji systems
VK_SPACE	20	SPACEBAR
VK_PRIOR	21	PAGE UP key
VK_NEXT	22	PAGE DOWN key
VK_END	23	END key
VK_HOME	24	HOME key
VK_LEFT	25	LEFT ARROW key
VK_UP	26	UP ARROW key
VK_RIGHT	27	RIGHT ARROW key
VK_DOWN	28	DOWN ARROW key
VK_SELECT	29	SELECT key
	2A	Specific to original equipment manufacturer
VK_EXECUTE	2B	EXECUTE key
VK_SNAPSHOT	2C	PRINT SCREEN key
VK_INSERT	2D	INS key
VK_DELETE	2E	DEL key
VK_HELP	2F	HELP key
	3A40	Undefined
VK_LWIN	5B	Left Windows key on a Microsoft Natural Keyboard
VK_RWIN	5C	Right Windows key on a Microsoft Natural Keyboard
VK_APPS	5D	Applications key on a Microsoft Natural Keyboard
	5E5F	Undefined
VK_NUMPAD0	60	Numeric keypad 0 key
VK_NUMPAD1	61	Numeric keypad 1 key
VK_NUMPAD2	62	Numeric keypad 2 key
VK_NUMPAD3	63	Numeric keypad 3 key
VK_NUMPAD4	64	Numeric keypad 4 key
VK_NUMPAD5	65	Numeric keypad 5 key
VK_NUMPAD6	66	Numeric keypad 6 key
VK_NUMPAD7	67	Numeric keypad 7 key
VK_NUMPAD8	68	Numeric keypad 8 key
VK_NUMPAD9	69	Numeric keypad 9 key
VK_MULTIPLY	6A	Multiply key
VK_ADD	6B	Add key
VK_SEPARATOR	6C	Separator key
VK_SUBTRACT	6D	Subtract key
VK_DECIMAL	6E	Decimal key
VK_DIVIDE	6F	Divide key
VK_F1	70	F1 key
VK_F2	71	F2 key
VK_F3	72	F3 key
VK_F4	73	F4 key
VK_F5	74	F5 key
VK_F6	75	F6 key
VK_F7	76	F7 key
VK_F8	77	F8 key
VK_F9	78	F9 key
VK_F10	79	F10 key
VK_F11	7A	F11 key
VK_F12	7B	F12 key
VK_F13	7C	F13 key
VK_F14	7D	F14 key
VK_F15	7E	F15 key
VK_F16	7F	F16 key
VK_F17	80H	F17 key
VK_F18	81H	F18 key
VK_F19	82H	F19 key
VK_F20	83H	F20 key
VK_F21	84H	F21 key
VK_F22	85H	F22 key (PPC only) Key used to lock device.
VK_F23	86H	F23 key
VK_F24	87H	F24 key
	888F	Unassigned
VK_NUMLOCK	90	NUM LOCK key
VK_SCROLL	91	SCROLL LOCK key
VK_LSHIFT	0xA0	Left SHIFT
VK_RSHIFT	0xA1	Right SHIFT
VK_LCONTROL	0xA2	Left CTRL
VK_RCONTROL	0xA3	Right CTRL
VK_LMENU	0xA4	Left ALT
VK_RMENU	0xA5	Right ALT
	BA-C0	Specific to original equipment manufacturer; reserved. See following tables.
	C1-DA	Unassigned
	DB-E2	Specific to original equipment manufacturer; reserved. See following tables.
	E3 – E4	Specific to original equipment manufacturer
	E5	Unassigned
	E6	Specific to original equipment manufacturer
VK_PACKET	E7	Used to pass Unicode characters as if they were keystrokes. If VK_PACKET is used with SendInput, then the Unicode character to be delivered should be placed into the lower 16 bits of the scan code. If a keyboard message is removed from the message queue and the virtual key is VK_PACKET, then the Unicode character will be the upper 16 bits of the lparam.
	E8	Unassigned
	E9-F5	Specific to original equipment manufacturer
VK_ATTN	F6	ATTN key
VK_CRSEL	F7	CRSEL key
VK_EXSEL	F8	EXSEL key
VK_EREOF	F9	Erase EOF key
VK_PLAY	FA	PLAY key
VK_ZOOM	FB	ZOOM key
VK_NONAME	FC	Reserved for future use
VK_PA1	FD	PA1 key
VK_OEM_CLEAR	FE	CLEAR key
VK_KEYLOCK	F22	Key used to lock device

Original equipment manufacturers should make special note of the VK key ranges reserved for specific original equipment manufacturer use: 2A, DBE4, E6, and E9F5.

In addition to the VK key assignments in the previous table, Microsoft has assigned the following specific original equipment manufacturer VK keys.

Symbolic constant	Hexadecimal value	Mouse or keyboard equivalent
VK_OEM_SCROLL	0x91	None
VK_OEM_1	0xBA	";:" for US
VK_OEM_PLUS	0xBB	"+" any country/region
VK_OEM_COMMA	0xBC	"," any country/region
VK_OEM_MINUS	0xBD	"-" any country/region
VK_OEM_PERIOD	0xBE	"." any country/region
VK_OEM_2	0xBF	"/?" for US
VK_OEM_3	0xC0	"`~" for US
VK_OEM_4	0xDB	"[{" for US
VK_OEM_5	0xDC	"\|" for US
VK_OEM_6	0xDD	"]}" for US
VK_OEM_7	0xDE	"'"" for US
VK_OEM_8	0xDF	None
VK_OEM_AX	0xE1	AX key on Japanese AX keyboard
VK_OEM_102	0xE2	"<>" or "\|" on RT 102-key keyboard

5. 如何POST一个WM_HOTKEY消息？

首先从上面MSDN中关于WM_HOTKEY的内容可以看到，如何填入wParam、lParam参数.

（转来一段）运用PostMessage(HWND_BROADCAST, WM_HOTKEY, 0, MAKELONG(MOD_ALT | MOD_CONTROL, VK_DELETE));来发送虚拟键盘，但是在winNT以后的系统里我们还有很多事情要做，比如：OpenDesktop()、OpenInputDesktop()、GetThreadDesktop()、SetThreadDesktop()、CloseDesktop()、GetUserObjectInformation()

代码如下：（直接PostMessage是没有起作用，下面这个做法，VK_DELETE换成其他键值也同样效果，为啥？）

#include "windows.h"
BOOL simulateAltControlDel();
void main()
{
    simulateAltControlDel();
}
BOOL simulateAltControlDel()
{
    HDESK   hdeskCurrent;
    HDESK   hdesk;
    HWINSTA hwinstaCurrent;
    HWINSTA hwinsta;
    // 
    // Save the current Window station
    // 
    hwinstaCurrent = GetProcessWindowStation();
    if (hwinstaCurrent == NULL)
        return FALSE;
    // 
    // Save the current desktop
    // 
    hdeskCurrent = GetThreadDesktop(GetCurrentThreadId());
    if (hdeskCurrent == NULL)
        return FALSE;
    // 
    // Obtain a handle to WinSta0 - service must be running
    // in the LocalSystem account
    // 
    hwinsta = OpenWindowStation("winsta0", FALSE,
                              WINSTA_ACCESSCLIPBOARD   |
                              WINSTA_ACCESSGLOBALATOMS |
                              WINSTA_CREATEDESKTOP     |
                              WINSTA_ENUMDESKTOPS      |
                              WINSTA_ENUMERATE         |
                              WINSTA_EXITWINDOWS       |
                              WINSTA_READATTRIBUTES    |
                              WINSTA_READSCREEN        |
                              WINSTA_WRITEATTRIBUTES);
    if (hwinsta == NULL)
        return FALSE;
    // 
    // Set the windowstation to be winsta0
    // 
    if (!SetProcessWindowStation(hwinsta))
     return FALSE;

    // 
    // Get the default desktop on winsta0
    // 
    hdesk = OpenDesktop("Winlogon", 0, FALSE,
                        DESKTOP_CREATEMENU |
              DESKTOP_CREATEWINDOW |
                        DESKTOP_ENUMERATE    |
                        DESKTOP_HOOKCONTROL  |
                        DESKTOP_JOURNALPLAYBACK |
                        DESKTOP_JOURNALRECORD |
                        DESKTOP_READOBJECTS |
                        DESKTOP_SWITCHDESKTOP |
                        DESKTOP_WRITEOBJECTS);
    if (hdesk == NULL)
       return FALSE;

    // 
    // Set the desktop to be "default"
    // 
    if (!SetThreadDesktop(hdesk))
       return FALSE;
    PostMessage(HWND_BROADCAST,WM_HOTKEY,0,MAKELPARAM(MOD_ALT|MOD_CONTROL,VK_DELETE));


    // 
    // Reset the Window station and desktop
    // 
    if (!SetProcessWindowStation(hwinstaCurrent))
       return FALSE;

    if (!SetThreadDesktop(hdeskCurrent))
    return FALSE;

    // 
    // Close the windowstation and desktop handles
    // 
    if (!CloseWindowStation(hwinsta))
        return FALSE;
    if (!CloseDesktop(hdesk))
        return FALSE;
    return TRUE;
}

偶一开始试验了发现不成功，后来冰河大哥告诉我说OpenDesktop("Winlogon", ......)本身需要LocalSystem权限，
果然如此，把它注册成服务，然后效果实现。相信如何注册成服务不用我说了吧。ok，我们想要的功能实现了。

他说的注册为服务应该是这个：Running CMD.EXE as Local System

原理清楚了，不过我还是到Google了搜了下，找到了两篇相关文章。
一篇就叫《利用服务创建SYSTEM权限CMD》，说不定就和这个小工具有关系。

另外一篇是一个国外的一个大牛在MSDN的Blog上的，就叫《Running CMD.EXE as Local System 》。

这个人说了一种直接用sc命令创建服务来运行SYSTEM权限的CMD的方法，测试了下，果然很好用。
我把它写成如下一个简单的批处理，同样可以得到SYSTEM权限的CMD：

sc Create SuperCMD binPath= "cmd /K start" type= own type= interact
sc start SuperCMD