Each type of hook enables an application to monitor a different aspect of the system's message-handling mechanism.
每种类型的钩子使应用程序能够监视系统的消息处理机制的不同方面。
钩子类型1-2：WH_CALLWNDPROC and WH_CALLWNDPROCRET Hooks
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.
The WH_CALLWNDPROCRET hook passes a pointer to a CWPRETSTRUCT structure to the hook procedure. The structure contains the return value from the window procedure that processed the message, as well as the message parameters associated with the message. Subclassing the window does not work for messages set between processes.
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 operati**. The WH_CBT hook is intended primarily for computer-based training (CBT) applicati**.
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.
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.
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.
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 the WH_JOURNALRECORD Hook. 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.
The WH_JOURNALPLAYBACK hook returns a time-out value. This value tells the system how many milliseconds to wait before processing the current message from the playback hook. This enables the hook to control the timing of the events it plays back.
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 the WH_JOURNALPLAYBACK Hook. The WH_JOURNALRECORD hook is a global hook — it cannot be used as a thread-specific hook.
The WH_KEYBOARD_LL hook enables you to monitor keyboard input events about to be posted in a thread input queue.
WH_KEYBOARD_LL钩子监视在线程输入队列中，即将被传递的键盘输入事件。
钩子类型10：WH_KEYBOARD Hook
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.
The WH_MOUSE_LL hook enables you to monitor mouse input events about to be posted in a thread input queue.
WH_MOUSE_LL钩子监视在线程输入队列中，即将被传递的鼠标输入事件。
钩子类型12：WH_MOUSE Hook
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.