C / C++ / MFC

12-Jan-06 22:50

We can set a window "always on top" by using SetWindowPos() with HWND_TOPMOST. I wonder is there a way to make a window is not only "always on top" but also "always activated". It means that window will be always activated, but we will still be able to activate another windows. Plz help me solve this problem. Tnx alot.

Stephen Hewitt12-Jan-06 23:49

12-Jan-06 23:49

Only one window can be the active window. We can't activate another window but still have the first active - That would mean there would be two active windows. What are you trying to achieve?

Steve

Roger Stoltz13-Jan-06 0:00

Roger Stoltz

13-Jan-06 0:00

What do you mean by "activated"?
Usually "activated" means that the window has the input focus which means that no other window will get keyboard input for instance.
Is this really what you want? (I don't think so, but that's just me...)
Only one window at any given time can be "active" in that sense.

Perhaps you mean that the title bar of the window should still look as if the window is "active" even if another window has got the input focus.
That's another thing and should be possible, but I don't have a solution for it.
However, I don't consider it very user friendly since the user will have multiple windows that seems to have input focus.

What is it you want to accomplish?

--
Roger

It's supposed to be hard, otherwise anybody could do it!

Stephen Hewitt13-Jan-06 0:14

13-Jan-06 0:14

This is possible and actually very easy.
See http://blogs.msdn.com/oldnewthing/archive/2003/10/29/55479.aspx

Steve

leenmie13-Jan-06 0:44

13-Jan-06 0:44

Tnx alot. Two windows cant be activated. But could we make a window always activated ??? I try to use PostMessage() with WM_MOUSEACTIVATE in a while loop but it make my program run very slowly and the result is not always as I want. Anyone have a solution ?

-- modified at 6:45 Friday 13th January, 2006

Stephen Hewitt13-Jan-06 1:06

13-Jan-06 1:06

Do you want your window to be the only activated window in the whole system or just within your application? Either way you could use the SetWindowsHookEx API to install a WH_CBT hook to do this. If it's system wide the hook procudure will have to live in a DLL further complicating you life.

Steve

Koushik Biswas13-Jan-06 13:51

Koushik Biswas

13-Jan-06 13:51

I am assuming you are writing the code for the window you want to keep always activated. If yes, you can handle "WM_ACTIVATEAPP" in its WndProc. This message is sent to any window that is about to lose focus or to gain focus, the difference between losing and gaining focus is the WPARAM - it is FALSE if it islosing focus.

Thus, you can use that message to trap the fact that you are about to lose focus (some other window is trying to come on top). Once you sense that, you can take corrective action by calling

SetWindowPos( hWnd, HWND_TOPMOST, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE );<br />
ShowWindow( hWnd, SW_SHOWNORMAL );

That should return the window to active state - quite rude to other windows though!

Now, assuming that you are NOT directly writing the code of this window, you can write a small hidden program that will always run in the background, and constantly call GetForegroundWindow() [see here[^]] or GetTopWindow() [see here[^]], and compare the HWND value it gets with the handle of your window. To do that, it must first get the HWND handle of your window, which it can initially get by calling FindWindow(). If it ever sees that the top window is something else than your window, it can call the same functions as described above with the handle of your window to bring it on top again.

Disclaimer - I have not tried this actually. Let me know if this works.

Koushik Biswas

-- modified at 19:55 Friday 13th January, 2006

toxcct13-Jan-06 0:53

toxcct

13-Jan-06 0:53

overload the WM_KILLFOCUS of your windows, and then, call WM_SETFOCUS from within...
this way, whenever the window looses the focus, it gets it back

TOXCCT >>> GEII power
[toxcct][VisualCalc 2.20][VisualCalc 3.0]

leenmie13-Jan-06 2:15

13-Jan-06 2:15

In function WindowProc(), I switch msg WM_KILLFOCUS and then, I PostMessage WM_SETFOCUS (i try SetFocus() function too), but it cant keep the focus for my window. When I click another windows, my window lose the focus. Is there anything wrong ?

FarPointer13-Jan-06 3:47

FarPointer

13-Jan-06 3:47

Map the WM_NCACTIVATE ,and in that set any of your child controls to set focus ;-

void CTestDlg::OnNcActivate(<br />
      BOOL bActive<br />
)<br />
{<br />
	int a;<br />
	c_edit.SetFocus ();//c_edit is a control variable of edit control <br />
        ::SendMessage (this->m_hWnd ,WM_ACTIVATE,0,0);<br />
		 //CDialog::OnNcActivate(true );<br />
}

-- modified at 9:50 Friday 13th January, 2006

Koushik Biswas13-Jan-06 13:55

Koushik Biswas

13-Jan-06 13:55

SetWindowPos( hWnd, HWND_TOPMOST, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE );<br />
ShowWindow( hWnd, SW_SHOWNORMAL );

leenmie13-Jan-06 15:47

Capture all keyboard input inside a dialog

13-Jan-06 15:47

I try the first, it make the window "always on top", not "always activated".

The second, I think it will not succeed. Because it is not really "always activated" : another window will be activated (by a click ex.), and then, we activate the window we want. That's what you do, but it's not the achieve.
Tnx alot.

-- modified at 21:48 Friday 13th January, 2006

kevincwong12-Jan-06 22:38

12-Jan-06 22:38

Hi,

I have a dialog will get input from a 2D barcode scanner,
about a couple hundred characters.

I already override the PreTranslateMessage but still
not sure what's best way to capture the scanner input
as stdin.

I think my problem is that I am not too familiar with
Windows messaging. So, When I got a lot messages
inside PreTranslateMessage, I don't know how to filter
out & convert the data I want.

Can someone give me some suggestions?

Thanks,

Kevin

Stephen Hewitt12-Jan-06 23:50

12-Jan-06 23:50

I'm not sure what you're asking....Does the scanner input come in a keyboard messages?

Steve

Rajesh R Subramanian13-Jan-06 0:31

Rajesh R Subramanian

13-Jan-06 0:31

kevincwong wrote:
Capture all keyboard input inside a dialog

You can do this by overriding PreTranslateMessage

append this code inside your PreTranslateMessage handler.

if(pMsg->message == WM_KEYDOWN)
{
//now the key pressed is available in
//pMsg->wParam... store it in a string or
//character variable and write it to a file
}</code>

Regards,
Rajesh R. Subramanian

You have an apple and me too. We exchange those and We have an apple each.
You have an idea and me too. We exchange those and We have two ideas each.

kevincwong13-Jan-06 6:02

13-Jan-06 6:02

Rajesh,

Great! that's exactly what I want. I know I read it from somewhere
before but just can not remember how to do so.

btw, when I pressed a key (for example 'a', the pMsg->wParm is 65,
']' is 221), I think the pMsg->wParm is the scancode (not ASCII code).

Am I correct?

Thank for you help!!

Kevin

James R. Twine13-Jan-06 6:24

James R. Twine

13-Jan-06 6:24

kevincwong wrote:
btw, when I pressed a key (for example 'a', the pMsg->wParm is 65,
']' is 221), I think the pMsg->wParm is the scancode (not ASCII code).

No, in the cases of the normal non-special keys, the values will be the ASCII codes for the keyboard key pressed (not the actual character received). So when you press <A> on the keyboard, you get a value of 65, which is the same as 'A'. This should be the code received regardless of things like SHIFT or CTRL key state.

Peace!

-=- James

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kevincwong13-Jan-06 7:03

13-Jan-06 7:03

Hi James,

That's what I guess with alphanumeric character, like 'A'.

But it does not explain ']' (pMsg->Param == 221).
The ASCII for for ']' is 93.

It looks like 221 - 128 = 93.

Do you know why?

Thanks,

Kevin

James R. Twine13-Jan-06 7:12

James R. Twine

13-Jan-06 7:12

   Hmmm! No idea. Maybe different local/keyboard settings than standard US-English?

   Maybe using MapVirtualKeyEx(...) with a MapType of 2 would help here?

   Peace!

-=- James

Rajesh R Subramanian13-Jan-06 18:51

Rajesh R Subramanian

13-Jan-06 18:51

Hi Kevin,

When some key is pressed, the value that arrives at

pMsg->wParam

will be equal to the Virtual Key code of that particular key. Please look up MSDN for more details about Virtual Key Codes. Say, for example, when the 'p' key is pressed, the value that arrives will be equal to

VK_P

which is the virtual key code of that key. If you need to know upper/lowercase detail too, use the

GetKeyState()

function to know if shift key is pressed or if CAPS LOCK is turned on.

Please let me know if this solved your problem.

Regards,
Rajesh R. Subramanian

You have an apple and me too. We exchange those and We have an apple each.
You have an idea and me too. We exchange those and We have two ideas each.

kevincwong15-Jan-06 18:21

15-Jan-06 18:21

Got it!

Thanks,

Kevin