为什么会执行两次？？？（与HOOK有关）

[jacky_shen]

在HOOK中截获一个键，然后去打开一个记事本，为什么会打开两次。
if (_WPARAM = VK_CONTROL) then ShellExecute(0, 'Open', 'notepad.exe', nil, nil, SW_SHOWDEFAULT);

[智商无下限]

把KEYDOWN和KEYPRESS分开处理！

[CloneCenter]

按一个键会产生两次键盘中断。

[票票飞扬]

是因为 KeyDown和KeyUp事件的原因。

[ahjoe]

同意，是KeyDown和KeyUp

[jacky_shen]

那么如何分开呢？

[ICMGDCHN]

关注ing,我也出现过这种问题还没解决

[大大怪老张]

加个标志是否可以。

bsign : boolean ;

if (_WPARAM = VK_CONTROL) then
if bsign = true then
begin
ShellExecute(0, 'Open', 'notepad.exe', nil, nil, SW_SHOWDEFAULT);
bsign := false ;
else
bsign := true ;

第一次检测到按键，标志：= true ，再次检测到按键如果标志=true，则执行操作。

[大大怪老张]

bsign : boolean ;

if (_WPARAM = VK_CONTROL) then
if bsign = true then
begin
ShellExecute(0, 'Open', 'notepad.exe', nil, nil, SW_SHOWDEFAULT);
bsign := false ;
end
else
bsign := true ;

忘了写end了。

[笑天居士]

通过判断lParam参数，可以实现：

Specifies the repeat count, scan code, extended-key flag, context code, previous key-state flag, and transition-state flag. This parameter can be a combination of the following values:

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's 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 a function key or a key on the numeric keypad. The value is 1 if the key is an extended key; otherwise, it is 0.
25-28 Reserved.
29 Specifies the context code. The value is 1 if the ALT key is down; otherwise, it is 0.
30 Specifies the previous key state. The value is 1 if the key is down before the message is sent; it is 0 if the key is up.
31 Specifies the transition state. The value is 0 if the key is being pressed and 1 if it is being released.


For more information about the lParam parameter, see Keystroke Message Flags.

第30、31位可以判断到是按下还是释放!

[ahjoe]

确定是KeyDown和KeyUp

[jacky_shen]

问题我自己已经搞定。