delphi 向Windows窗口发送Alt组合键的问题

但就是没有很好解决问题。 

之前找到一个能正确发送的code:(Alt+A) 

PostMessage(hWnd,WM_SYSKEYDOWN,VK_MENU,0); 

PostMessage(hWnd,WM_SYSKEYDOWN,0x41,0); 

Sleep(50); 

PostMessage(hWnd,WM_SYSKEYUP,0x41,0); 

PostMessage(hWnd,WM_SYSKEYUP,VK_MENU,0); 

有人解释说，按下组合键的时候系统是发两条消息的 

但是看到Win32 SDK,感觉上就发一次就可以了…… 

偶然间又看到最后一个参数的说明，有所发现！先看WM_SYSKEYDOWN的help 

The WM_SYSKEYDOWN message is posted to the window with the keyboard focus when the user holds down the ALT key and then presses another key. It also occurs when no window currently has the keyboard focus; in this case, the WM_SYSKEYDOWN message is sent to the active window. The window that receives the message can distinguish between these two contexts by checking the context code in the lKeyData parameter. 

WM_SYSKEYDOWN 
nVirtKey = (int) wParam; // virtual-key code 
lKeyData = lParam; // key data 


Parameters 

nVirtKey 

Value of wParam. Specifies the virtual-key code of the key being pressed. 

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. The value is the number of times the keystroke is repeated as a result of the user holding down the key.
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 1 if the ALT key is down while the key is pressed; it is 0 if the WM_SYSKEYDOWN message is posted to the active window because no window has the keyboard focus. 
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_SYSKEYDOWN message. 


之前曾经修改过keyData的16－23位为VK_MENU，第30位参数为1,但没效果 

请看位29的说明！！ 

The value is 1 if the ALT key is down while the key is pressed; 

当值为1时表示ALT键被按下！这不正是我需要的吗？于是把29位设置为1,函数调用变成 

PostMessage(hWnd,WM_SYSKEYDOWN,0x41,1<<29); 

经过测试，发现这个就是Alt+A的效果！！原来这么简单，但为什么很多人弄得那么复杂，我当时查找的时候也是迷惘啊，浪费了N多小时。 

类似有个WM_SYSKEYUP,WM_SYSCHAR(这个不知道干什么用) 

记录一下免得 又便成了 找不到资料的傻子了 

postmessage(edit1.handle,wm_keydown,vk_down,$20000000） 

Ctrl ： $10000000; 
Shift： $08000000; 
Alt:20000000 

Delphi键盘按键伪码 

if key = chr(VK_RETURN) then... 

常数名称 十六进制值 十进制值 对应按键 
VK_LBUTTON 01 1 鼠标的左键 
VK_RBUTTON 02 2 鼠标的右键 
VK-CANCEL 03 3 Contol-break 执行 
VK_MBUTTON 04 4 鼠标的中键（三按键鼠标) 
VK_BACK 08 8 Backspace键 
VK_TAB 09 9 Tab键 
VK_CLEAR 0C 12 Clear键 
VK_RETURN 0D 13 Enter键 
VK_SHIFT 10 16 Shift键 
VK_CONTROL 11 17 Ctrl键 
VK_MENU 12 18 Alt键 
VK_PAUSE 13 19 Pause键 
VK_CAPITAL 14 20 Caps Lock键 
VK_ESCAPE 1B 27 Ese键 
VK_SPACE 20 32 Spacebar键 
VK_PRIOR 21 33 Page Up键 
VK_NEXT 22 34 Page Domw键 
VK_END 23 35 End键 
VK_HOME 24 36 Home键 
VK_LEFT 25 37 LEFT ARROW 键(←) 
VK_UP 26 38 UP ARROW键(↑) 
VK_RIGHT 27 39 RIGHT ARROW键(→) 
VK_DOWN 28 40 DOWN ARROW键(↓) 
VK_SELECT 29 41 SELECT键 
VK_EXECUTE 2B 43 EXECUTE键 
VK_SNAPSHOT 2C 44 Print Screen键 
VK_INSERT 2D 45 Ins键 
VK_DELETE 2E 46 Del键 
VK_HELP 2F 47 Help键 
VK_0 30 48 0键 
VK_1 31 49 1键 
VK_2 32 50 2键 
VK_3 33 51 3键 
VK_4 34 52 4键 
VK_5 35 53 5键 
VK_6 36 54 6键 
VK_7 37 55 7键 
VK_8 38 56 8键 
VK_9 39 57 9键 
VK_A 41 65 A键 
VK_B 42 66 B键 
VK_C 43 67 C键 
VK_D 44 68 D键 
VK_E 45 69 E键 
VK_F 46 70 F键 
VK_G 47 71 G键 
VK_H 48 72 H键 
VK_I 49 73 I键 
VK_J 4A 74 J键 
VK_K 4B 75 K键 
VK_L 4C 76 L键 
VK_M 4D 77 M键 
VK_N 4E 78 N键 
VK_O 4F 79 O键 
VK_P 50 80 P键 
VK_Q 51 81 Q键 
VK_R 52 82 R键 
VK_S 53 83 S键 
VK_T 54 84 T键 
VK_U 55 85 U键 
VK_V 56 86 V键 
VK_W 57 87 W键 
VK_X 58 88 X键 
VK_Y 59 89 Y键 
VK_BZ 5A 90 Z键 
VK_NUMPAD0 60 96 数字键0键 
VK_NUMPAD1 61 97 数字键1键 
VK_NUMPAD2 62 98 数字键2键 
VK_NUMPAD3 63 99 数字键3键 
VK_NUMPAD4 64 100 数字键4键 
VK_NUMPAD5 65 101 数字键5键 
VK_NUMPAD6 66 102 数字键6键 
VK_NUMPAD7 67 103 数字键7键 
VK_NUMPAD8 68 104 数字键8键 
VK_NUMPAD9 69 105 数字键9键 
VK_MULTIPLY 6A 106 *键 
VK_ADD 6B 107 +键 
VK_SEPARATOR 6C 108 Separator键 
VK_SUBTRACT 6D 109 -键 
VK_DECIMAL 6E 110 .键 
VK_DIVIDE 6F 111 键 
VK_F1 70 112 F1键 
VK_F2 71 113 F2键 
VK_F3 72 114 F3键 
VK_F4 73 115 F4键 
VK_F5 74 116 F5键 
VK_F6 75 117 F6键 
VK_F7 76 118 F7键 
VK_F8 77 119 F8键 
VK_F9 78 120 F9键 
VK_F10 79 121 F10键 
VK_F11 7A 122 F11键 
VK_F12 7B 123 F12键 
VK_NUMLOCK 90 144 Num Lock 键 
VK_SCROLL 91 145 Scroll Lock键