[solved]WM_KEYDOWN VK_LCONTROL

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vivik

Joined: 29 Oct 2016
Posts: 671

vivik 19 Mar 2017, 01:01

I'm learning winapi, and I need to get state of ctrl key, presset it currently or not.

I expected to receive VK_LCONTROL VK_RCONTROL messages for it (0xa2 0xa3), but instead I'm only getting VK_CONTROL (0x11). And as for alt, I'm not getting WM_KEYDOWN at all.

What's this about? So I have to use GetKeyState, instead of just waiting for WM_KEYDOWN?

Last edited by vivik on 19 Mar 2017, 10:12; edited 1 time in total

19 Mar 2017, 01:01

AsmGuru62

Joined: 28 Jan 2004
Posts: 1625
Location: Toronto, Canada

AsmGuru62 19 Mar 2017, 03:05

From MSDN it looks like you need to wait for WM_KEYDOWN with VK_CONTROL and then detect L/R with GetKeyState():

Code:

if (msg == WM_KEYDOWN)
{
        if (wParam == VK_CONTROL)
        {
                if (GetKeyState (VK_LCONTROL) & 0x8000)
                {
                        // LEFT Control Key
                }
                else
                {
                        // RIGHT Control Key
                }
        }
}

19 Mar 2017, 03:05

sinsi

Joined: 10 Aug 2007
Posts: 789
Location: Adelaide

sinsi 19 Mar 2017, 04:11

Maybe bit 24 of lParam?

Quote:

Indicates whether the key is an extended key, such as the right-hand ALT and CTRL keys that appear on an enhanced 101- or 102-key keyboard. The value is 1 if it is an extended key; otherwise, it is 0.

Apparently VK_LCONTROL VK_RCONTROL are only used for GetKeyState and GetAsyncKeyState.

19 Mar 2017, 04:11

guignol

Joined: 06 Dec 2008
Posts: 763

guignol 19 Mar 2017, 05:32

VK_ is a key number

19 Mar 2017, 05:32

bitRAKE

Joined: 21 Jul 2003
Posts: 4042
Location: vpcmpistri

bitRAKE 19 Mar 2017, 05:46

Have you tried any of those Message Hook/Spy tools? They are very useful for figuring out what Windows is doing.

Spy++ comes with Visual Studio, but other similar programs exist.
http://mdb-blog.blogspot.com/2010/11/microsoft-spy-or-spyxx-for-download.html

http://www.catch22.net/software/winspy-17

http://windowdetective.sourceforge.net/

Description:	left alt, left ctl, right alt, right ctl, left shift, right shift *( fExtended flags means right. )
Filesize:	37.83 KB
Viewed:	5824 Time(s)

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19 Mar 2017, 05:46

vivik

Joined: 29 Oct 2016
Posts: 671

vivik 19 Mar 2017, 08:38

@bitRAKE
Third link worked, thank you! First didn't show messages for my app for some reason (worked fine for others), and second only shows information about window itself.

I also fixed some other bug with it (I was getting too much WM_PAINT), really usefull.

So alt received not with WM_KEYDOWN, but with WM_SYSKEYDOWN. According to this link https://msdn.microsoft.com/en-us/library/windows/desktop/gg153546(v=vs.85).aspx the only SYSKEYDOWN keys are alt and f10, and I must to pass them to DefWindowProc in order to not break anything. Weird. But now I understand why walking doesn't work in half life 2 on windows 7, as a bonus.

As of VK_LCONTROL VK_RCONTROL, looks like they are indeed for GetKeyState() only. Thanks, everyone!

19 Mar 2017, 08:38

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