Subclassing and Hooking with Visual Basic

Part III. Hooking

This section devotes individual chapters to the following hooks:

WH_CALLWNDPROC

Intercepts messages sent using the SendMesssage API function

WH_CALLWNDPROCRET

Intercepts messages after they have been processed by their window procedure

WH_CBT

Used to create Computer Based Training (CBT) applications

WH_DEBUG

Intercepts calls to an installed hook’s filter function

WH_FOREGROUNDIDLE

Called when an application is about to enter an idle state

WH_GETMESSAGE

Intercepts posted (and not sent) messages

WH_JOURNALPLAYBACK

Posts prerecorded messages to the raw input thread’s message queue so that they may be processed (“played back”) by the system.

WH_JOURNALRECORD

Intercept mouse, keyboard, and other hardware messages received by the system

WH_KEYBOARD and WH_KEYBOARD_LL

Intercepts keyboard messages

WH_MOUSE and WH_MOUSE_LL

Intercept mouse messages

WH_MSGFILTER

Intercepts sent messages produced by menus, dialog boxes, message boxes, and scroll bars

WH_SYSMSGFILTER

Intercepts sent messages produced by menus, dialog boxes, message boxes, and scroll bars on a system-wide basis

WH_SHELL

Intercepts messages that notify an application of actions occurring to it either through user intervention or through a change in the system’s state

Each chapter will discuss a hook in detail. The chapters will begin by discussing the hook and providing relevant background information. I will use examples to aid in these discussions. Each chapter will end with a discussion of the problems ...