程序是这么写的！
procedure SendShift(H: HWnd; Down: Boolean);
var vKey, ScanCode, wParam: Word;
lParam: longint;
begin
vKey:= $10;
ScanCode:= MapVirtualKey(vKey, 0);
wParam:= vKey or ScanCode shl 8;
lParam:= longint(ScanCode) shl 16 or 1;
if not(Down) then lParam:= lParam or $C0000000;
SendMessage(H, WM_KEYDOWN, vKey, lParam);
end;问题1 ScanCode:= MapVirtualKey(vKey, 0);为什么要这么写有什么含义吗？
这么写有什么用意
问题2 lParam:= longint(ScanCode) shl 16 or 1;同上
问题3 if not(Down) then lParam:= lParam or $C0000000;
这我就更加不明白了！
大家能不能详细一点的回答啊！我可是个菜鸟啊！说的不清楚我就看不明白！不好意思！有麻烦大家了！
procedure SendShift(H: HWnd; Down: Boolean);
var vKey, ScanCode, wParam: Word;
lParam: longint;
begin
vKey:= $10;
ScanCode:= MapVirtualKey(vKey, 0);
wParam:= vKey or ScanCode shl 8;
lParam:= longint(ScanCode) shl 16 or 1;
if not(Down) then lParam:= lParam or $C0000000;
SendMessage(H, WM_KEYDOWN, vKey, lParam);
end;问题1 ScanCode:= MapVirtualKey(vKey, 0);为什么要这么写有什么含义吗？
这么写有什么用意
问题2 lParam:= longint(ScanCode) shl 16 or 1;同上
问题3 if not(Down) then lParam:= lParam or $C0000000;
这我就更加不明白了！
大家能不能详细一点的回答啊！我可是个菜鸟啊！说的不清楚我就看不明白！不好意思！有麻烦大家了！
第二，就是longint(ScanCode) 右移16位，再和1进行“或”运算；
第三，如果“非”Down，那么lParam等于lParam 和 $C0000000 进行或运算。
但愿能给你一点启示，OK？
MapVirtualKey的用法
-----------------------------------------------------------
The MapVirtualKey function translates (maps) a virtual-key code into a scan code or character value, or translates a scan code into a virtual-key code. UINT MapVirtualKey(
UINT uCode, // virtual-key code or scan code
UINT uMapType // translation to perform
);
Parameters
uCode
Specifies the virtual-key code or scan code for a key. How this value is interpreted depends on the value of the uMapType parameter.
uMapType
Specifies the translation to perform. The value of this parameter depends on the value of the uCode parameter: Value Meaning
0 uCode is a virtual-key code and is translated into a scan code. If it is a virtual-key code that does not distinguish between left- and right-hand keys, the left-hand scan code is returned. If there is no translation, the function returns 0.
1 uCode is a scan code and is translated into a virtual-key code that does not distinguish between left- and right-hand keys. If there is no translation, the function returns 0.
2 uCode is a virtual-key code and is translated into an unshifted character value in the low-order word of the return value. Dead keys (diacritics) are indicated by setting the top bit of the return value. If there is no translation, the function returns 0.
3 uCode is a scan code and is translated into a virtual-key code that distinguishes between left- and right-hand keys. If there is no translation, the function returns 0.
Return Values
The return value is either a scan code, a virtual-key code, or a character value, depending on the value of uCode and uMapType. If there is no translation, the return value is zero.Res
An application can use MapVirtualKey to translate scan codes to the virtual-key code constants VK_SHIFT, VK_CONTROL, and VK_MENU, and vice versa. These translations do not distinguish between the left and right instances of the shift, ctrl, or alt keys. An application can get the scan code corresponding to the left or right instance of one of these keys by calling MapVirtualKey with uCode set to one of the following virtual-key code constants. VK_LSHIFT VK_RSHIFT
VK_LCONTROL VK_RCONTROL
VK_LMENU VK_RMENU
These left- and right-distinguishing constants are available to an application only through the GetKeyboardState, SetKeyboardState, GetAsyncKeyState, GetKeyState, and MapVirtualKey functions.WM_KEYDOWN的用法
------------------------------------------------
WM_KEYDOWN
The WM_KEYDOWN message is posted to the window with the keyboard focus when a nonsystem key is pressed. A nonsystem key is a key that is pressed when the alt key is not pressed. WM_KEYDOWN
nVirtKey = (int) wParam; // virtual-key code
lKeyData = lParam; // key data
Parameters
nVirtKey
Value of wParam. Specifies the virtual-key code of the nonsystem key.
lKeyData
Value of lParam. Specifies the repeat count, scan code, extended-key flag, context code, previous key-state flag, and transition-state flag, as shown in the following table. Value Description
0–15 Specifies the repeat count for the current message. The value is the number of times the keystroke is auto-repeated as a result of the user holding down the key. If the keystroke is held long enough, multiple messages are sent. However, the repeat count is not cumulative.
16–23 Specifies the scan code. The value depends on the original equipment manufacturer (OEM).
24 Specifies whether the key is an extended key, such as the right-hand alt and ctrl keys that appear on an enhanced 101- or 102-key keyboard. The value is 1 if it is an extended key; otherwise, it is 0.
25–28 Reserved; do not use.
29 Specifies the context code. The value is always 0 for a WM_KEYDOWN message.
30 Specifies the previous key state. The value is 1 if the key is down before the message is sent, or it is 0 if the key is up.
31 Specifies the transition state. The value is always 0 for a WM_KEYDOWN message.
Return Values
An application should return zero if it processes this message. Default Action
If the f10 key is pressed, the DefWindowProc function sets an internal flag. When DefWindowProc receives the WM_KEYUP message, the function checks whether the internal flag is set and, if so, sends a WM_SYSCOMMAND message to the top-level window. The wParam parameter of the message is set to SC_KEYMENU. Res
Because of the autorepeat feature, more than one WM_KEYDOWN message may be posted before a WM_KEYUP message is posted. The previous key state (bit 30) can be used to determine whether the WM_KEYDOWN message indicates the first down transition or a repeated down transition. For enhanced 101- and 102-key keyboards, extended keys are the right alt and ctrl keys on the main section of the keyboard; the ins, del, home, end, page up, page down and arrow keys in the clusters to the left of the numeric keypad; and the divide (/) and enter keys in the numeric keypad. Other keyboards may support the extended-key bit in the lKeyData parameter.
vk_LButton = $01;
vk_RButton = $02;
vk_Cancel = $03;
vk_MButton = $04; { NOT contiguous with L & RBUTTON }
vk_Back = $08;
vk_Tab = $09;
vk_Clear = $0C;
vk_Return = $0D;
vk_Shift = $10;
vk_Control = $11;
vk_Menu = $12;
vk_Pause = $13;
vk_Capital = $14;
vk_Escape = $1B;
vk_Space = $20;
vk_Prior = $21;
vk_Next = $22;
vk_End = $23;
vk_Home = $24;
vk_Left = $25;
vk_Up = $26;
vk_Right = $27;
vk_Down = $28;
vk_Select = $29;
vk_Print = $2A;
vk_Execute = $2B;
vk_SnapShot = $2C;
vk_Copy = $2C not used by keyboards }
vk_Insert = $2D;
vk_Delete = $2E;
vk_Help = $2F;
vk_A thru vk_Z are the same as their ASCII equivalents: 'A' thru 'Z' }
vk_0 thru vk_9 are the same as their ASCII equivalents: '0' thru '9' }
vk_NumPad0 = $60;
vk_NumPad1 = $61;
vk_NumPad2 = $62;
vk_NumPad3 = $63;
vk_NumPad4 = $64;
vk_NumPad5 = $65;
vk_NumPad6 = $66;
vk_NumPad7 = $67;
vk_NumPad8 = $68;
vk_NumPad9 = $69;
vk_Multiply = $6A;
vk_Add = $6B;
vk_Separator = $6C;
vk_Subtract = $6D;
vk_Decimal = $6E;
vk_Divide = $6F;
vk_F1 = $70;
vk_F2 = $71;
vk_F3 = $72;
vk_F4 = $73;
vk_F5 = $74;
vk_F6 = $75;
vk_F7 = $76;
vk_F8 = $77;
vk_F9 = $78;
vk_F10 = $79;
vk_F11 = $7A;
vk_F12 = $7B;
vk_F13 = $7C;
vk_F14 = $7D;
vk_F15 = $7E;
vk_F16 = $7F;
vk_F17 = $80;
vk_F18 = $81;
vk_F19 = $82;
vk_F20 = $83;
vk_F21 = $84;
vk_F22 = $85;
vk_F23 = $86;
vk_F24 = $87;
vk_NumLock = $90;
vk_Scroll = $91; Tab是#9
回车是＃13，换行是＃10等？ The following table lists the virtual key codes defined in the Windows unit:
Virtual Key Code Corresponding key
VK_LBUTTON Left mouse button
VK_RBUTTON Right mouse button
VK_CANCEL Control+Break
VK_MBUTTON Middle mouse button
VK_BACK Backspace key
VK_TAB Tab key
VK_CLEAR Clear key
VK_RETURN Enter key
VK_SHIFT Shift key
VK_CONTROL Ctrl key
VK_MENU Alt key
VK_PAUSE Pause key
VK_CAPITAL Caps Lock key
VK_KANA Used with IME
VK_HANGUL Used with IME
VK_JUNJA Used with IME
VK_FINAL Used with IME
VK_HANJA Used with IME
VK_KANJI Used with IME
VK_CONVERT Used with IME
VK_NONCONVERT Used with IME
VK_ACCEPT Used with IME
VK_MODECHANGE Used with IME
VK_ESCAPE Esc key
VK_SPACE Space bar
VK_PRIOR Page Up key
VK_NEXT Page Down key
VK_END End key
VK_HOME Home key
VK_LEFT Left Arrow key
VK_UP Up Arrow key
VK_RIGHT Right Arrow key
VK_DOWN Down Arrow key
VK_SELECT Select key
VK_PRINT Print key (keyboard-specific)
VK_EXECUTE Execute key
VK_SNAPSHOT Print Screen key
VK_INSERT Insert key
VK_DELETE Delete key
VK_HELP Help key
VK_LWIN Left Windows key (Microsoft keyboard)
VK_RWIN Right Windows key (Microsoft keyboard)
VK_APPS Applications key (Microsoft keyboard)
VK_NUMPAD0 0 key (numeric keypad)
VK_NUMPAD1 1 key (numeric keypad)
VK_NUMPAD2 2 key (numeric keypad)
VK_NUMPAD3 3 key (numeric keypad)
VK_NUMPAD4 4 key (numeric keypad)
VK_NUMPAD5 5 key (numeric keypad)
VK_NUMPAD6 6 key (numeric keypad)
VK_NUMPAD7 7 key (numeric keypad)
VK_NUMPAD8 8 key (numeric keypad)
VK_NUMPAD9 9 key (numeric keypad)
VK_MULTIPLY Multiply key (numeric keypad)
VK_ADD Add key (numeric keypad)
VK_SEPARATOR Separator key (numeric keypad)
VK_SUBTRACT Subtract key (numeric keypad)
VK_DECIMAL Decimal key (numeric keypad)
VK_DIVIDE Divide key (numeric keypad)
VK_F1 F1 key
VK_F2 F2 key
VK_F3 F3 key
VK_F4 F4 key
VK_F5 F5 key
VK_F6 F6 key
VK_F7 F7 key
VK_F8 F8 key
VK_F9 F9 key
VK_F10 F10 key
VK_F11 F11 key
VK_F12 F12 key
VK_F13 F13 key
VK_F14 F14 key
VK_F15 F15 key
VK_F16 F16 key
VK_F17 F17 key
VK_F18 F18 key
VK_F19 F19 key
VK_F20 F20 key
VK_F21 F21 key
VK_F22 F22 key
VK_F23 F23 key
VK_F24 F24 key
VK_NUMLOCK Num Lock key
VK_SCROLL Scroll Lock key
VK_LSHIFT Left Shift key (only used with GetAsyncKeyState and GetKeyState)
VK_RSHIFT Right Shift key (only used with GetAsyncKeyState and GetKeyState)
VK_LCONTROL Left Ctrl key (only used with GetAsyncKeyState and GetKeyState)
VK_RCONTROL Right Ctrl key (only used with GetAsyncKeyState and GetKeyState)
VK_LMENU Left Alt key (only used with GetAsyncKeyState and GetKeyState)
VK_RMENU Right Alt key (only used with GetAsyncKeyState and GetKeyState)
VK_PROCESSKEY Process key
VK_ATTN Attn key
VK_CRSEL CrSel key
VK_EXSEL ExSel key
VK_EREOF Erase EOF key
VK_PLAY Play key
VK_ZOOM Zoom key
VK_NONAME Reserved for future use
VK_PA1 PA1 key
VK_OEM_CLEAR Clear key
VK_LBUTTON = 1;
VK_RBUTTON = 2;
VK_CANCEL = 3;
VK_MBUTTON = 4; { NOT contiguous with L & RBUTTON }
VK_BACK = 8;
VK_TAB = 9;
VK_CLEAR = 12;
VK_RETURN = 13;
VK_SHIFT = $10;
VK_CONTROL = 17;
VK_MENU = 18;
VK_PAUSE = 19;
VK_CAPITAL = 20;
VK_KANA = 21;
VK_HANGUL = 21;
VK_JUNJA = 23;
VK_FINAL = 24;
VK_HANJA = 25;
VK_KANJI = 25;
VK_CONVERT = 28;
VK_NONCONVERT = 29;
VK_ACCEPT = 30;
VK_MODECHANGE = 31;
VK_ESCAPE = 27;
VK_SPACE = $20;
VK_PRIOR = 33;
VK_NEXT = 34;
VK_END = 35;
VK_HOME = 36;
VK_LEFT = 37;
VK_UP = 38;
VK_RIGHT = 39;
VK_DOWN = 40;
VK_SELECT = 41;
VK_PRINT = 42;
VK_EXECUTE = 43;
VK_SNAPSHOT = 44;
VK_INSERT = 45;
VK_DELETE = 46;
VK_HELP = 47;
{ VK_0 thru VK_9 are the same as ASCII '0' thru '9' ($30 - $39) }
{ VK_A thru VK_Z are the same as ASCII 'A' thru 'Z' ($41 - $5A) }
VK_LWIN = 91;
VK_RWIN = 92;
VK_APPS = 93;
VK_NUMPAD0 = 96;
VK_NUMPAD1 = 97;
VK_NUMPAD2 = 98;
VK_NUMPAD3 = 99;
VK_NUMPAD4 = 100;
VK_NUMPAD5 = 101;
VK_NUMPAD6 = 102;
VK_NUMPAD7 = 103;
VK_NUMPAD8 = 104; VK_NUMPAD9 = 105;
VK_MULTIPLY = 106;
VK_ADD = 107;
VK_SEPARATOR = 108;
VK_SUBTRACT = 109;
VK_DECIMAL = 110;
VK_DIVIDE = 111;
VK_F1 = 112;
VK_F2 = 113;
VK_F3 = 114;
VK_F4 = 115;
VK_F5 = 116;
VK_F6 = 117;
VK_F7 = 118;
VK_F8 = 119;
VK_F9 = 120;
VK_F10 = 121;
VK_F11 = 122;
VK_F12 = 123;
VK_F13 = 124;
VK_F14 = 125;
VK_F15 = 126;
VK_F16 = 127;
VK_F17 = 128;
VK_F18 = 129;
VK_F19 = 130;
VK_F20 = 131;
VK_F21 = 132;
VK_F22 = 133;
VK_F23 = 134;
VK_F24 = 135;
VK_NUMLOCK = 144;
VK_SCROLL = 145;
{ VK_L & VK_R - left and right Alt, Ctrl and Shift virtual keys.
Used only as parameters to GetAsyncKeyState() and GetKeyState().
No other API or message will distinguish left and right keys in this way. }
VK_LSHIFT = 160;
VK_RSHIFT = 161;
VK_LCONTROL = 162;
VK_RCONTROL = 163;
VK_LMENU = 164;
VK_RMENU = 165;
VK_PROCESSKEY = 229;
VK_ATTN = 246;
VK_CRSEL = 247;
VK_EXSEL = 248;
VK_EREOF = 249;
VK_PLAY = 250;
VK_ZOOM = 251;
VK_NONAME = 252;
VK_PA1 = 253;
VK_OEM_CLEAR = 254 但愿有帮助。
语法我都是明白的，但是就不知道有什么意图啊！为什么这么写！