LPARAM, WPARAM Queries

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Hi,
Can Any one explain how to retrieve the value and modify it of lparam, wparam variable when keystrokes are generated in keyboard hooks?

Thanks in advance

Posted 2-May-11 3:36am

R. S. Verma

Updated 2-May-11 8:05am

Hans Dietrich

v2

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Olivier Levrey · Accepted Answer · 2011-05-02T03:42:00

Solution 1

Usually it is done by overriding the PreTranslateMessage function:

Application level:
http://msdn.microsoft.com/fr-fr/library/cw1sb70c(v=vs.90).aspx[^]

Window level:
http://msdn.microsoft.com/en-us/library/kkbhxcs2(v=vs.80).aspx[^]

However, I don't recommand to change their value...

Posted 2-May-11 3:42am

Olivier Levrey

Comments

Sergey Alexandrovich Kryukov 2-May-11 9:54am

Great solution, a 5+++++
--SA

Olivier Levrey 2-May-11 10:00am

Thank you SA.

Niklas L 2-May-11 14:20pm

Good recommendation. 5. If OP wants to change the values using a hook, it's probably nothing I want to have installed on my machine.

Hans Dietrich · Accepted Answer · 2011-05-02T08:04:00

Solution 2

If you really mean keyboard hooks, and not just key handling (as Olivier discussed), then the answer to your question is found in MSDN:

LRESULT CALLBACK KeyboardProc(
  int code,       // hook code
  WPARAM wParam,  // virtual-key code
  LPARAM lParam   // keystroke-message information
);

Posted 2-May-11 8:04am

Hans Dietrich

Comments

Niklas L 2-May-11 14:17pm

Fived.

Olivier Levrey 3-May-11 3:43am

Good answer as well. Have my 5.

R. S. Verma · Accepted Answer · 2011-05-02T22:04:00

Thanks for your great replies! First of all, i'm using the hook type of WH_JOURNALRECORD . I understand how to work with the hook but the actuall problem is that i need to update the value of lparam
...... LRESULT CALLBACK JournalRecordProc(int code,WPARAM wparam,LPARAM lparam);
so that i can change character from 'a' to 'A' at the time of keydown and before forwarding the message to the destination window
.
.
and this can be done by overriding using
PreTranslateMessageEx(mesg); function
how to override and how to change lparam value plz explain
thankx...