C / C++ / MFC

4-Aug-05 7:27

As you know, the windows standard for select all is Control-A.
There is a program I am workin at creating a 3rd party app for that uses Ctrl-A for another purpose. I am wanting to, within my app, remap ctrl-a back to the standard, and assign a new sequence to the old task it once did.

I am creating a DLL hook in my app and can capture single keyboard events, but I am having trouble determining how to capture and remap ctrl-A for this application.

In it's simplest form, the following is what I am trying to achieve. If (Control & A), display messagebox!

LRESULT __declspec(dllexport)__stdcall  CALLBACK KeyboardProc(<br />
                            int nCode, <br />
                           WPARAM wParam, <br />
                            LPARAM lParam)<br />
{<br />
        if (wParam==0x041 & VK_CONTROL) <br />
  		MessageBox(0, Success!, "Message", MB_OK);<br />
	<br />
	LRESULT RetVal = CallNextHookEx( hkb, nCode, wParam, lParam );	<br />
	return  RetVal;<br />
}

Thanks for any assistance!

Jeff

Blake Miller4-Aug-05 7:56

4-Aug-05 7:56

Instead, try catching all the key events related to the 'A' character and use GetAsyncKeyState to see if the CTRL is down at the same time.

Jumpin' Jeff4-Aug-05 8:21

4-Aug-05 8:21

Thanks!
I thought I had tried that, but must have messed something up.

Here it is again altered to the current state, and working....

LRESULT __declspec(dllexport)__stdcall  CALLBACK KeyboardProc(<br />
                            int nCode, <br />
                           WPARAM wParam, <br />
                            LPARAM lParam)<br />
{<br />
	if (((DWORD)lParam & 0x40000000) &&(HC_ACTION==nCode)) <br />
	{		<br />
		if (wParam==0x041)//'A' Key<br />
		{<br />
			BOOL bControlKeyDown = FALSE;<br />
			bControlKeyDown=GetAsyncKeyState(VK_CONTROL)>>((sizeof(SHORT) * 8) - 1);<br />
			if (bControlKeyDown != 0)<br />
  				MessageBox(0, "Success!, "Message", MB_OK);<br />
		}<br />
	}<br />
<br />
	LRESULT RetVal = CallNextHookEx( hkb, nCode, wParam, lParam );	<br />
	return  RetVal;<br />
}

Blake Miller4-Aug-05 8:28

4-Aug-05 8:28

You could probably safely reduce some of your logic from this:

BOOL bControlKeyDown = FALSE;
bControlKeyDown=GetAsyncKeyState(VK_CONTROL)>>((sizeof(SHORT) * 8) - 1);
if (bControlKeyDown != 0)

To this:

if( GetAsyncKeyState(VK_CONTROL) & 0x8000 )

At least that is how I check, and not in about 6 years has there ever been a problem Unsure | :~

Jumpin' Jeff4-Aug-05 14:22

4-Aug-05 14:22

As a fairly new coder, I appriciate your insight! Thank you very much!
Big Grin | :-D

Jumpin' Jeff4-Aug-05 15:54

4-Aug-05 15:54

To continue on this, How do I now terminate this task, so that I can send a new task in it's place?

Jumpin' Jeff5-Aug-05 2:37

5-Aug-05 2:37

Blake Miller wrote:
if( GetAsyncKeyState(VK_CONTROL) & 0x8000 )

Can you tell me where I can find a listing of these masks?

Even the 0x40000000? All I can determin is that 0x8000 is for the control keys, and that 0x40000000 limits me to the key up.

Obviously, I need to change this to key down, as the task is complete before the message box displays curently. Removing this mask helped me determine this with a return value of -1...

Last question...
What reference material would you recommend reading for this type of hook information?

Jeff

Blake Miller5-Aug-05 4:05

running with less cpu usage

5-Aug-05 4:05

You need to read the MSDN for each function VERY carefully.
The GetAsyncKeyState function determines whether a key is up or down at the time the function is called, and whether the key was pressed after a previous call to GetAsyncKeyState. ... If the most significant bit is set, the key is down, and if the least significant bit is set, the key was pressed after the previous call to GetAsyncKeyState.

KeyboardProc Function

lParam
[in] Specifies the repeat count, scan code, extended-key flag, context code, previous key-state flag, and transition-state flag. For more information about the lParam parameter, see Keystroke Message Flags. This parameter can be one or more of the following values.
0-15
Specifies the repeat count. The value is the number of times the keystroke is repeated as a result of the user's holding down the key.
16-23
Specifies the scan code. The value depends on the OEM.
24
Specifies whether the key is an extended key, such as a function key or a key on the numeric keypad. The value is 1 if the key is an extended key; otherwise, it is 0.
25-28
Reserved.
29
Specifies the context code. The value is 1 if the ALT key is down; otherwise, it is 0.
30
Specifies the previous key state. The value is 1 if the key is down before the message is sent; it is 0 if the key is up.
31
Specifies the transition state. The value is 0 if the key is being pressed and 1 if it is being released.

0x40000000 = 0100 0000 0000 0000 0000 0000 0000 0000 in binary.
Which means you are testing if bit 30 is set.

0x8000 = 1000 0000 0000 0000 in binary.
Which means you are testing if bit 15 is set.

Using NtCreateFile

Chintoo7234-Aug-05 7:25

Chintoo723

4-Aug-05 7:25

I want to use NtCreateFile in my application, but I cant get a simple program calling NtCreateFile to compile with Visual Studio. I installed DDK but dont know how to get started with a simple example of using NtCreateFile. Can someone help or give pointers to introductory tutorials on this topic? Thanks.

Re: Using NtCreateFile

Toby Opferman4-Aug-05 11:54

Toby Opferman

4-Aug-05 11:54

NtCreateFile is an undocumented API and should not be required for standard WIN32 Applications which can simply use "CreateFile" as they are the same API.

Now, if you are writing a driver the API that should be documented in the DDK header files is "ZwCreateFile". This encapsulates the overhead of creating a IRP_MJ_CREATE IRP and handling it for ease of use with your driver. Of course the down fall of using such an API is that it is not flexible and can only be used at IRQL PASSIVE.

ZwCreateFile[^]

8bc7c0ec02c0e404c0cc0680f7018827ebee

Chintoo7234-Aug-05 7:21

Chintoo723

4-Aug-05 7:21

Suppose a program is doing some processing and the CPU shoots up to 99% (by design and not by error). How do I make it use only 50% of CPU? I have seen a program somewhere that always shows 50% in the task manager. Any idea how to achieve this behaviour? Thanks.

Re: running with less cpu usage

Blake Miller4-Aug-05 7:49

GetThemeColor of disabled BP_PUSHBUTTON

4-Aug-05 7:49

1. You can reduce the priority of your application or of specific worker threads.

The SetThreadPriority function sets the priority value for the specified thread. This value, together with the priority class of the thread's process, determines the thread's base priority level.

Why not just let the OS figure it out? Although I realize that a ill-behaved foreground application can really seem to take over your computer!

RazorBridge4-Aug-05 7:10

RazorBridge

4-Aug-05 7:10

I want to obtain the theme colour of the border of a disabled button. I try;

GetThemeColor(hTheme, BP_PUSHBUTTON, PBS_DISABLED, TMT_BORDERCOLOR, &rgb );

but the returned color is darker than the colour produced by DrawThemeBackground call.

I've tried various other property IDs but to no avail.

Does anyone know how to obtain the correct theme colour?

Re: GetThemeColor of disabled BP_PUSHBUTTON

Jose Lamas Rios4-Aug-05 18:12

Jose Lamas Rios

4-Aug-05 18:12

RazorBridge wrote:
I've tried various other property IDs but to no avail.

I don't know for sure, but have you tried these in particular?

TMT_EDGELIGHTCOLOR       // edge color (3804)
TMT_EDGEHIGHLIGHTCOLOR   // edge color (3805)
TMT_EDGESHADOWCOLOR      // edge color (3806)
TMT_EDGEDKSHADOWCOLOR    // edge color (3807)
TMT_EDGEFILLCOLOR        // edge color (3808)

--
jlr
http://jlamas.blogspot.com/[^]

Re: GetThemeColor of disabled BP_PUSHBUTTON

RazorBridge4-Aug-05 21:49

RazorBridge

4-Aug-05 21:49

Yes, tried them all but no luck.

Disallowing Ctrl-Alt-Del

#realJSOP4-Aug-05 6:26

#realJSOP

4-Aug-05 6:26

Target OS = WinXP/SP2
Using VC6

I'm trying to modify Tom Delascia's TaskKeyHook DLL as follows

<br />
LRESULT CALLBACK MyTaskKeyHookLL(int nCode, WPARAM wp, LPARAM lp)<br />
{<br />
	KBDLLHOOKSTRUCT *pkh = (KBDLLHOOKSTRUCT *) lp;<br />
<br />
	if (nCode == HC_ACTION) <br />
	{<br />
		BOOL bCtrlKeyDown =	GetAsyncKeyState(VK_CONTROL)>>((sizeof(SHORT) * 8) - 1);<br />
		BOOL bDelKeyDown  = (pkh->vkCode == VK_DELETE);<br />
		BOOL bAltKeyDown  = (pkh->flags & LLKHF_ALTDOWN);<br />
<br />
		if (  (pkh->vkCode==VK_ESCAPE && bCtrlKeyDown)        // Ctrl+Esc<br />
			||(pkh->vkCode==VK_TAB    && bAltKeyDown)         // Alt+TAB<br />
			||(pkh->vkCode==VK_ESCAPE && bAltKeyDown)         // Alt+Esc<br />
			||(pkh->vkCode==VK_LWIN || pkh->vkCode==VK_RWIN)  // Start Menu<br />
			||(bCtrlKeyDown && bAltKeyDown && bDelKeyDown))   // ctrl+alt+del<br />
		{<br />
			if (g_bBeep && (wp == WM_SYSKEYDOWN || wp == WM_KEYDOWN))<br />
			{<br />
				MessageBeep(0); // only beep on downstroke if requested<br />
			}<br />
			return 1; // gobble it: go directly to jail, do not pass go<br />
		}<br />
	}<br />
	return CallNextHookEx(g_hHookKbdLL, nCode, wp, lp);<br />
}<br />

My line of code is the addition of the last comparison in the if statement:

||(bCtrlKeyDown && bAltKeyDown && bDelKeyDown)

This does not have the desired affect of simply eating the keystroke. Why not, and how do I get to where I want to go if a global hook isn't going to work?

------- sig starts

"I've heard some drivers saying, 'We're going too fast here...'. If you're not here to race, go the hell home - don't come here and grumble about going too fast. Why don't you tie a kerosene rag around your ankles so the ants won't climb up and eat your candy ass..." - Dale Earnhardt

"...the staggering layers of obscenity in your statement make it a work of art on so many levels." - Jason Jystad, 10/26/2001

Graham Bradshaw4-Aug-05 6:53

Graham Bradshaw

4-Aug-05 6:53

I always thought the whole point of the Ctrl-Alt-Del sequence was that it *couldn't* be interupted by application programs, but was under the sole control of the OS, so that it could be trusted. I'm sure you're not, but if you could catch this combination, what's to stop you putting up a dialog box just like a standard logon box, and stealing passwords?

#realJSOP4-Aug-05 8:26

#realJSOP

4-Aug-05 8:26

I didn't ask why it's done, I asked how to get around it.

I'm building a "kiosk"-style app that will be put on over 100 laptops, and I don't want the users to be able to exit our app at all. The app already goes full-screen (no titlebar, menu, toolbar, or statusbar), can't be minimized, and requires a password to shut it down.

I've also disabled any way to change tasks using normal avenues (alt-tab, etc).

Now, I want to keep them from shutting down or restarting the box.

Is there a way to do this, or not?

------- sig starts

"I've heard some drivers saying, 'We're going too fast here...'. If you're not here to race, go the hell home - don't come here and grumble about going too fast. Why don't you tie a kerosene rag around your ankles so the ants won't climb up and eat your candy ass..." - Dale Earnhardt

"...the staggering layers of obscenity in your statement make it a work of art on so many levels." - Jason Jystad, 10/26/2001

Maximilien4-Aug-05 9:16

Maximilien

4-Aug-05 9:16

I did a quick search, I remembered that the GINA dll who isresponsible for the logon process might also be used when doing a log-off.

one thing that came up was :

The purpose of a GINA DLL is to provide customizable user identification and authentication procedures. The default GINA does this by delegating SAS event monitoring to Winlogon, which receives and processes CTL+ALT+DEL secure attention sequences (SASs). A custom GINA is responsible for setting itself up to receive SAS events (other than the default CTRL+ALT+DEL SAS event), and notifying Winlogon when SAS events occur. Winlogon will evaluate its state to determine what is required to process the custom GINA's SAS. This processing usually includes calls to the GINA's SAS processing functions.

maybe this can lead you to something usefull.

Maximilien Lincourt
Your Head A Splode - Strong Bad

Graham Bradshaw4-Aug-05 10:37

Graham Bradshaw

4-Aug-05 10:37

Try here[^] and here[^] (2nd question).

Tom Archer4-Aug-05 11:54

Tom Archer

4-Aug-05 11:54

One way is to install a CBT hook as opposed to a keyboard hook.

Tom Archer - Visual C++ MVP
Archer Consulting Group.com