Hook处理函数中lParam参数的处理

LRESULT CALLBACK KeyboardProc(int iCode, WPARAM wParam, LPARAM lParam)
{
         KBDLLHOOKSTRUCT* pStruct = (KBDLLHOOKSTRUCT*)lParam;

 

         //Specifies the transition state.

         //The value is 0 if the key is pressed and 1 if it is being released.

         if(pStruct->flags != 0)
         {
              //不处理
         }
         else
         {
              //处理
         }
}

 

 

 

附：KBDLLHOOKSTRUCT Structure

 

The KBDLLHOOKSTRUCT structure contains information about a low-level keyboard input event.

Syntax

typedef struct {
DWORD vkCode;
DWORD scanCode;
DWORD flags;
DWORD time;
ULONG_PTR dwExtraInfo;
} KBDLLHOOKSTRUCT, *PKBDLLHOOKSTRUCT;

Members

vkCode

Specifies a virtual-key code. The code must be a value in the range 1 to 254.

scanCode

Specifies a hardware scan code for the key.

flags

Specifies the extended-key flag, event-injected flag, context code, and transition-state flag. This member is specified as follows. An application can use the following values to test the keystroke flags.

Value	Purpose
LLKHF_EXTENDED	Test the extended-key flag.
LLKHF_INJECTED	Test the event-injected flag.
LLKHF_ALTDOWN	Test the context code.
LLKHF_UP	Test the transition-state flag.

0

Specifies 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.

1-3

Reserved.

4

Specifies whether the event was injected. The value is 1 if the event was injected; otherwise, it is 0.

5

Specifies the context code. The value is 1 if the ALT key is pressed; otherwise, it is 0.

6

Reserved.

7

Specifies the transition state. The value is 0 if the key is pressed and 1 if it is being released.

time

Specifies the time stamp for this message, equivalent to what GetMessageTime would return for this message.

dwExtraInfo

Specifies extra information associated with the message.

Structure Information

Header	Declared in Winuser.h, include Windows.h
Minimum operating systems	Windows NT 4.0 SP3