摘自：http://topic.csdn.net/u/20090228/16/c31dc299-a563-47df-a914-3def1ba08926.html
LRESULT CALLBACK KeyboardProc( int code, WPARAM wParam, LPARAM lParam);Parameterscode[in] Specifies a code the hook procedure uses to determine how to process the message. If code is less than zero, the hook procedure must pass the message to the CallNextHookEx function without further processing and should return the value returned by CallNextHookEx. This parameter can be one of the following values.HC_ACTIONThe wParam and lParam parameters contain information about a keystroke message.HC_NOREMOVEThe wParam and lParam parameters contain information about a keystroke message, and the keystroke message has not been removed from the message queue. (An application called the PeekMessage function, specifying the PM_NOREMOVE flag.)wParam[in] Specifies the virtual-key code of the key that generated the keystroke message.lParam[in] Specifies the repeat count, scan code, extended-key flag, context code, previous key-state flag, and transition-state flag. For more information about the lParam parameter, see Keystroke Message Flags. This parameter can be one or more of the following values. 0-15Specifies 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.16-23Specifies the scan code. The value depends on the OEM.24Specifies 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 0.25-28Reserved.29Specifies the context code. The value is 1 if the ALT key is down; otherwise, it is 0.30Specifies 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.31Specifies the transition state. The value is 0 if the key is being pressed and 1 if it is being released.
