HookTypes Fields

The HookTypes type exposes the following members.

Fields

	Name	Description
	CallWndProc	The WH_CALLWNDPROC and WH_CALLWNDPROCRET hooks enable you to monitor messages sent to window procedures. The system calls a WH_CALLWNDPROC hook procedure before passing the message to the receiving window procedure, and calls the WH_CALLWNDPROCRET hook procedure after the window procedure has processed the message.
	CallWndProcRet	The WH_CALLWNDPROC and WH_CALLWNDPROCRET hooks enable you to monitor messages sent to window procedures. The system calls a WH_CALLWNDPROC hook procedure before passing the message to the receiving window procedure, and calls the WH_CALLWNDPROCRET hook procedure after the window procedure has processed the message.
	CBT	The system calls a WH_CBT hook procedure before activating, creating, destroying, minimizing, maximizing, moving, or sizing a window; before completing a system command; before removing a mouse or keyboard event from the system message queue; before setting the input focus; or before synchronizing with the system message queue. The value the hook procedure returns determines whether the system allows or prevents one of these operations. The WH_CBT hook is intended primarily for computer-based training (CBT) applications.
	Debug	The system calls a WH_DEBUG hook procedure before calling hook procedures associated with any other hook in the system. You can use this hook to determine whether to allow the system to call hook procedures associated with other types of hooks.
	ForegroundIdle	The WH_FOREGROUNDIDLE hook enables you to perform low priority tasks during times when its foreground thread is idle. The system calls a WH_FOREGROUNDIDLE hook procedure when the application's foreground thread is about to become idle.
	GetMessage	The WH_GETMESSAGE hook enables an application to monitor messages about to be returned by the GetMessage or PeekMessage function. You can use the WH_GETMESSAGE hook to monitor mouse and keyboard input and other messages posted to the message queue.
	Hardware	A nonstandard hardware message hook called whenever the application calls the GetMessage() or PeekMessage() function and there is a hardware event (other than a mouse or keyboard event) to process.
	JournalPlayback	The WH_JOURNALPLAYBACK hook enables an application to insert messages into the system message queue. You can use this hook to play back a series of mouse and keyboard events recorded earlier by using WH_JOURNALRECORD. Regular mouse and keyboard input is disabled as long as a WH_JOURNALPLAYBACK hook is installed. A WH_JOURNALPLAYBACK hook is a global hook—it cannot be used as a thread-specific hook.
	JournalRecord	The WH_JOURNALRECORD hook enables you to monitor and record input events. Typically, you use this hook to record a sequence of mouse and keyboard events to play back later by using WH_JOURNALPLAYBACK. The WH_JOURNALRECORD hook is a global hook—it cannot be used as a thread-specific hook.
	Keyboard	The WH_KEYBOARD hook enables an application to monitor message traffic for WM_KEYDOWN and WM_KEYUP messages about to be returned by the GetMessage or PeekMessage function. You can use the WH_KEYBOARD hook to monitor keyboard input posted to a message queue.
	KeyboardLL	The WH_KEYBOARD_LL hook enables you to monitor keyboard input events about to be posted in a thread input queue.
	Mouse	The WH_MOUSE hook enables you to monitor mouse messages about to be returned by the GetMessage or PeekMessage function. You can use the WH_MOUSE hook to monitor mouse input posted to a message queue.
	MouseLL	The WH_MOUSE_LL hook enables you to monitor mouse input events about to be posted in a thread input queue.
	MsgFilter	The WH_MSGFILTER and WH_SYSMSGFILTER hooks enable you to monitor messages about to be processed by a menu, scroll bar, message box, or dialog box, and to detect when a different window is about to be activated as a result of the user's pressing the ALT+TAB or ALT+ESC key combination. The WH_MSGFILTER hook can only monitor messages passed to a menu, scroll bar, message box, or dialog box created by the application that installed the hook procedure. The WH_SYSMSGFILTER hook monitors such messages for all applications.
	Shell	A shell application can use the WH_SHELL hook to receive important notifications. The system calls a WH_SHELL hook procedure when the shell application is about to be activated and when a top-level window is created or destroyed.
	SysMsgFilter	The WH_MSGFILTER and WH_SYSMSGFILTER hooks enable you to monitor messages about to be processed by a menu, scroll bar, message box, or dialog box, and to detect when a different window is about to be activated as a result of the user's pressing the ALT+TAB or ALT+ESC key combination. The WH_MSGFILTER hook can only monitor messages passed to a menu, scroll bar, message box, or dialog box created by the application that installed the hook procedure. The WH_SYSMSGFILTER hook monitors such messages for all applications.

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