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Index > Windows > VB - > ASM emulate SendKeys

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r22



Joined: 27 Dec 2004
Posts: 805
r22
Emulating sendkeys does not involve using the sendmessage wm_settext window API.
For this sample I will be using two API's found in user32.dll
I will assume you already have the window handle for the program you want to emulate keystrokes to.

Code:
keybd_event
SetForegroundWindow

.data
StrToSend db 'Hello NotePad',0

.code
..Start:
push ebp
mov ebp,esp

push [WindowHandle]
call [SetForegroundWindow]

push StrToSend
call SendKeys

mov esp,ebp
pop ebp
ret 0

SendKeys:
.theStr equ ebp-8
  push ebp
  mov ebp,esp
  push esi
  mov esi, [.theStr]
.LoopToNull:
  cmp byte[esi],0
  je .AllDone
  movzx eax,byte[esi]
  push eax ;save it for 2nd call

  push 0 ;extra info
  push 1 ;flag
  push 0 ;key ScanCode
  push eax ;Virtual Keycode using ASCII
  call [keybd_event]
  pop eax ;get saved VK code
  push 0 ;extra info
  push 3 ;flags for key UP
  push 0 ;scan code
  push eax ;VK Code
  call [keybd_event]

  add esi,1
  jmp .LoopToNull
.AllDone:
  pop esi
  mov esp,ebp
  pop ebp
  ret 4    


That is a better SendKey emulation.

moderator says: please use teh [ code ] tags.
Post 10 Mar 2005, 02:21
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Madis731



Joined: 25 Sep 2003
Posts: 2140
Location: Estonia
Madis731
It's all fun and interesting, but please, use [ code] tags
Code:
;to help others read better    
[ /code]
Thank you!
Post 11 Mar 2005, 10:14
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r22



Joined: 27 Dec 2004
Posts: 805
r22
Everyone's a critic Razz
Post 16 Mar 2005, 06:20
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null



Joined: 03 Jan 2005
Posts: 1
Location: massachusetts
null
lol Smile hi

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::as water fills the lungs, light empties the mind::
Post 20 Apr 2005, 03:04
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BigVent



Joined: 28 May 2008
Posts: 24
BigVent
r22,

I really appreciate the code provided. Could you elaborate to a newb on what this does and what I can do with this.

I'm trying to make a program that will interact with my remote login (give password to login screen), then click three buttons and exit.

Any help is appreciated!!!
Post 28 May 2008, 13:40
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asmhack



Joined: 01 Feb 2008
Posts: 431
asmhack
BigVent wrote:
r22,

I really appreciate the code provided. Could you elaborate to a newb on what this does and what I can do with this.

I'm trying to make a program that will interact with my remote login (give password to login screen), then click three buttons and exit.

Any help is appreciated!!!


Code:
invoke keybd_event,VK_NUMLOCK,0,KEYEVENTF_EXTENDEDKEY or 0,0
invoke keybd_event,VK_NUMLOCK,0,KEYEVENTF_EXTENDEDKEY or KEYEVENTF_KEYUP,0
    


virtual key codes:
http://msdn.microsoft.com/en-us/library/ms927178.aspx
Post 28 May 2008, 15:17
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BigVent



Joined: 28 May 2008
Posts: 24
BigVent
Thank you asmhack!

--edit--

By chance... do you have an example program that will pass a pre-defined password to current window?

-- End edit--

~BIgVent
Post 28 May 2008, 15:36
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asmhack



Joined: 01 Feb 2008
Posts: 431
asmhack
well the above code will send keys to foreground/focused edit box for example, the other way is to obtain hwnd (handle of the edit box) and use SetWindowText api function
Post 28 May 2008, 15:52
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bitRAKE



Joined: 21 Jul 2003
Posts: 3055
Location: vpcmipstrm
bitRAKE
Maybe something like:
Code:
     push esi
    mov esi,StrToSend

       push [WindowHandle]
 call [SetForegroundWindow]

SendKeys:
     lodsb
       movzx ecx,al
        jecxz .AllDone

  push 0          ; extra info
        push 3          ; flags for key UP
  push 0          ; scan code
 push ecx        ; VK Code

       push 0          ; extra info
        push 1          ; flag
      push 0          ; key ScanCode
      push ecx        ; Virtual Keycode using ASCII

   call [keybd_event]

      call [keybd_event]

      jmp SendKeys

.AllDone:
   pop esi
     retn    
Idea Not really an emulation of SendKeys anymore.

(all those extra instructions just make my head hurt, lol)

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Post 29 May 2008, 01:43
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