Discussion :

[Fox_magic]

Est-ce que quelqu'un sait comment implémenter un hook système pour appeler une application Delphi qui n'a pas le focus. J'ai déjà vu ca mais je ne sais plus où. Je crois qu'il faut intercepter la boucle des messages Windows.

Merci de votre réponse.

[Nono40]

J'ai réalisé un KeyLogger il y a quelque-temps, il utilise un hook système sur le clavlier, tu peux trouver le source ici :
http://nono40.fr.st/sources/source0007.html

[Bendes]

Il y a aussi beaucoup plus simple, l'API RegisterHotKey:

The RegisterHotKey function defines a system-wide hot key.

Syntax

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. If this parameter is NULL, WM_HOTKEY messages are posted to the message queue of the calling thread and must be processed in the message loop.
id
[in] Specifies the 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 (the range returned by the GlobalAddAtom function). To avoid conflicts with hot-key identifiers defined by other shared DLLs, a DLL should use the GlobalAddAtom function to obtain the hot-key identifier.
fsModifiers
[in] Specifies keys that must be pressed in combination with the key specified by the uVirtKey parameter in order to generate the WM_HOTKEY message. The fsModifiers parameter can be a combination of the following values.
MOD_ALT
Either ALT key must be held down.
MOD_CONTROL
Either CTRL key must be held down.
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 Value

If the function succeeds, the return value is nonzero.

If the function fails, the return value is zero. To get extended error information, call GetLastError.



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.

This function cannot associate a hot key with a window created by another thread.

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.

Windows NT4 and Windows 2000/XP: The F12 key is reserved for use by the debugger at all times, so it should not be registered as a hot key. Even when you are not debugging an application, F12 is reserved in case a kernel-mode debugger or a just-in-time debugger is resident.

[Fox_magic]

Merci à tous les deux.

J'ai de plus trouvé un exemple de la fonction RegisterHotKey dans le composant TJvApplicationHotKey de la JVCL.