Key loger

Posted on 1998-10-22
Last Modified: 2010-04-30
How do you get a form that does not have focus to "see" what keys are being pressed. I want to make a key loger. I have done this and I tryed to use it but as soon as the form lost focus it stoped logging keys pressed. Please help.
Question by:rpg_rpg
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Author Comment

ID: 1441116
Edited text of question

Expert Comment

ID: 1441117
I needed the same functions in my printscreen utility. The API-Call you need is GetAsyncKeyState ...

Here is my example:
Paste this code in a module

Public Declare Function GetKeyboardState Lib "user32" (kbArray As KeyboardBytes) As Long
Public Declare Function SetKeyboardState Lib "user32" (kbArray As KeyboardBytes) As Long
Public Declare Function GetKeyState Lib "user32" (ByVal nVirtKey As Long) As Integer

Public Declare Function GetAsyncKeyState Lib "user32" (ByVal vKey As Long) As Integer
Public Declare Sub Sleep Lib "kernel32" (ByVal dwMilliseconds As Long)

Public Type KeyboardBytes
    kbByte(0 To 255) As Byte
End Type

Public kbArray As KeyboardBytes
Public Const VK_SNAPSHOT = &H2C
Public Const VK_ALT = &H12

Paste this code in the form_load part

        If (GetAsyncKeyState(VK_SNAPSHOT)) Then
            If (GetAsyncKeyState(VK_ALT)) Then
                MsgBox "Alt And Print pressed"
                MsgBox "Print pressed"
            End If
            kbArray.kbByte(VK_SNAPSHOT) = 0
            kbArray.kbByte(VK_ALT) = 0
            SetKeyboardState kbArray
        End If
        Sleep 25

Don´t forget the DoEvents and the sleep, because the endless-loop this would be important for the performance of you app.

Author Comment

ID: 1441118
This is really close. But I am not real versed in API. If you could please tell me how to "see" a certen key other then print and alt+print. What is &H2C  and &H12 mean and how did you get those values? I hope you are not mad at my slowness. I know this is a good example. I just don't get it. Thanks...
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Expert Comment

ID: 1441119
The hexadecimal values are the constants for virtual keys. If you can´t find the definition of the virtual keys in your help-file or the api-text viewer (in constants) post your e-mail adress and i´ll mail it to you.


Author Comment

ID: 1441120
Gee... now I really feal dumb... I looked in both places and loaded all aviable files with the api-text viewer and could not find anything at all. Please send email to        

If I had any more points to give you I would. Thanks again...

Expert Comment

ID: 1441121
I just sent you the definitions...

Author Comment

ID: 1441122
Thanks a lot. I got it to work! Sorry for all the extra work I put you through. You did great. If there was a higher grade or I had more points I would give them to you!!!! OH... You need to answer with some thing... Go ahead.

Accepted Solution

Geffl earned 200 total points
ID: 1441123
with some thing...


fine that it works!

Author Comment

ID: 1441124
Adjusted points to 205

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