Detect Ctrl key pressed - C / C++ / MFC Discussion Boards

Christian Graus13-Jul-05 18:38

13-Jul-05 18:38

Yes, it's possible to write a handler for any uncaught exceptions for your applications. I'm not sure if it's done by a try/catch at the top level, or if some other mechanism exists though.

Christian Graus - Microsoft MVP - C++

Re: At exit

Toby Opferman13-Jul-05 19:37

Toby Opferman

13-Jul-05 19:37

The debugger should catch it and then you fix the problem.

8bc7c0ec02c0e404c0cc0680f7018827ebee

Re: At exit

Alexander ^M.,14-Jul-05 2:05

Alexander ^M.,

14-Jul-05 2:05

SetUnhandledExceptionFilter should be the thing you are looking for.
You can set a global exception filter with it.

Don't try it, just do it! Wink | ;-)

Docking Resizable Dialog box

mlsa13-Jul-05 15:55

mlsa

13-Jul-05 15:55

Hi everybody, I need your help.
I have a resizable dialog box with some controls (button, edit box, list box, etc). I have a Class that derive from « Paolo Messina CResizable » class. Every things works well.
Now I want to dock that dialog box (docking the dialog to the main frame). I try to do it, but it doesn’t work.
So, any ideas are welcome even if I would restart from scratch.
Thanks.

Re: Docking Resizable Dialog box

Stlan13-Jul-05 21:39

Stlan

13-Jul-05 21:39

Perhaps you can use the excellent resizable control bar[^] from Cristi Posea.

Re: Docking Resizable Dialog box

mlsa14-Jul-05 9:25

mlsa

14-Jul-05 9:25

Thanks,
But it cann't help me because i want my controls inside a dockable dialog to
be resizable like in CResizableLib of Paolo Messina.

Re: Docking Resizable Dialog box

Stlan14-Jul-05 19:31

Stlan

14-Jul-05 19:31

But you can derive Cristi's CSizingControlBar and put anything you want inside. I made it several months ago with a resizable child dialog containing listview, static and button controls. You only need to reposition the child dialog when the control bar is resized, then to override the OnSize handler in the child dialog to reposition correctly its controls.

Detect Ctrl key pressed

Ravi Bhavnani13-Jul-05 14:00

Ravi Bhavnani

13-Jul-05 14:00

I'm trying to detect when the user presses Ctrl/End. My PreTranslateMsg() override always computes the Ctrl key as not being pressed. Obviously, I'm doing something wrong. A gentle nudge in the right direction would be appreciated. Smile | :)

BOOL CMyCtrl::PreTranslateMessage (MSG* pMsg) 
{
  // Check if the Ctrl key is pressed
  BYTE pressedKeys [256];
  ZeroMemory (pressedKeys, sizeof (pressedKeys));
  VERIFY (::GetKeyboardState (pressedKeys));
  bool bCtrl = (pressedKeys [VK_CONTROL] & 255) == 255;
 
  // Override handling of specific keystrokes
  if (pMsg->message == WM_KEYDOWN) {
      switch (pMsg->wParam) {
        case VK_DELETE:
          m_pModel->notifyDeleteKey();
          break;
 
        case VK_RETURN:
          m_pModel->notifyEnterKey();
          break;
 
        case VK_HOME:
        case VK_END:
        case VK_LEFT:
        case VK_RIGHT:
        case VK_UP:
        case VK_DOWN:
          m_pModel->notifyNavKey (pMsg->wParam, bCtrl);
          break;
      }
  }
 
  return CWnd::PreTranslateMessage(pMsg);
}

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Re: Detect Ctrl key pressed

Christian Graus13-Jul-05 14:11

Christian Graus

13-Jul-05 14:11

Does End send WM_KEYDOWN or WM_CHAR ? If so, I'd use GetAsycKeyState to check if Control was down at the same time.

Christian Graus - Microsoft MVP - C++

Re: Detect Ctrl key pressed

Blake Miller14-Jul-05 4:39

Blake Miller

14-Jul-05 4:39

I am with Christian on this one. When I track regular virtual key presses, I always use GetAsycKeyState to test for the CTRL, SHIFT, etc. I have always experienced seriously mixed results with the GetKeyState function, so I don't use GetKeyState anymore.

This note in MSDN for GetKeyState about sums it up for me:
The key status returned from this function changes as a thread reads key messages from its message queue. The status does not reflect the interrupt-level state associated with the hardware. Use the GetAsyncKeyState function to retrieve that information.

Re: Detect Ctrl key pressed

Jack Puppy13-Jul-05 14:33

Jack Puppy

13-Jul-05 14:33

This is what I use...

<br />
if (pMsg->message == WM_KEYDOWN && pMsg->wParam == VK_END)<br />
{<br />
    BOOL bCtrlKeyDown = ((GetKeyState(VK_CONTROL) & ~1) != 0);<br />
      <br />
    if (bCtrlKeyDown)<br />
        AfxMessageBox(_T("woof, woof"));<br />
}<br />

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Re: Detect Ctrl key pressed

Aamir Butt13-Jul-05 20:15

Aamir Butt

13-Jul-05 20:15

if ((GetKeyState(VK_CONTROL) & 0x8000) )

This works for me nicely.

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My Articles

Thanks, all!

Ravi Bhavnani14-Jul-05 6:20

Ravi Bhavnani

14-Jul-05 6:20

Gak! I was &ing with 255 instead of 0x8000! Blush | :O

Thanks, guys!

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Worker thread question

Tom Wright13-Jul-05 12:26

Tom Wright

13-Jul-05 12:26

When I create my worker thread and pass a char array, will my data be lost if in my main app I wrote over my char array with new data? Here is my thread creation code:

<br />
		CWinThread* thread = AfxBeginThread(MyIOThread, this, THREAD_PRIORITY_NORMAL, 0, CREATE_SUSPENDED);<br />
		thread->m_bAutoDelete = TRUE;<br />
		thread->ResumeThread();<br />
<br />

Here is my worker code:

<br />
UINT CLAQTermDlg::MyIOThread(LPVOID pParam )<br />
{<br />
	CLAQTermDlg * myDlg = (CLAQTermDlg *)pParam;<br />
	<br />
	::MessageBox(NULL, myDlg->sText, "In my Thread", MB_OK );<br />
	return 0; //Thread completed successfully<br />
}<br />

Will the myDlg->sText be over written if in my main app I write over it with something else?

Thanks

Tom Wright
tawright915@yahoo.com

Re: Worker thread question

Blake Miller13-Jul-05 13:00

Blake Miller

13-Jul-05 13:00

Yes. Threads share the same memory space as the other threads within the program.
Worse, if you modify that same string from your main thread and worker thread at the same time, you might get some unprdictable and undesireable results.
Data access like that should be protected with a CriticalSection.

Re: Worker thread question

Tom Wright14-Jul-05 5:24

Tom Wright

14-Jul-05 5:24

Blake two quick questions

1. Would I put my critical section around my char array before I make my call to AfxBeginThread, or do it in my thread around the myDlg->sText char array.

2. Would it be wise to have another char array in my thread that I move this data off to and release my critical section?

Sorry I forgot a question.....If I create a char array in my thread does it have it own unique memory space each time a thread is created?

Thanks

Tom Wright
tawright915@yahoo.com

Re: Worker thread question

Blake Miller14-Jul-05 6:18

Blake Miller

14-Jul-05 6:18

1. You need to protect a string at the time the string is accessed.

If you really want to display the messagebox, I would make a local copy, but protect the copy process with the critical section.

UINT CLAQTermDlg::MyIOThread(LPVOID pParam )
{
CLAQTermDlg * myDlg = (CLAQTermDlg *)pParam;

CString csMessage;
EnterCriticalSection(...);
csMessage = myDlg->sText;
LeaveCriticalSection(...);

::MessageBox(NULL, csMessage, "In my Thread", MB_OK );
return 0; //Thread completed successfully
}

2. If you need the data longer, then make a variable as part of your thread class or a local variable in the thread function, and perform a protected copy, similar to above example. You also need to use same critical section in other parts of your code wherever the myDlg->sText is modified or accessed.

3. The array would be unique if it is local to the thread function or else if it is a member variable of a derived thread class, since you would be creating an instance of the thread class for each thread which is run. Just don't declare the member variable as static or it is shared among all instances of a class.

Reading a .prn file

bugDanny13-Jul-05 11:05

bugDanny

13-Jul-05 11:05

I'm trying to write a program that is based off of data from a database program. The only problem is, I want data from the database program that is only available if I print it to the printer. However, I can choose the 'print to file' option and the information is put in a .prn file. My question, then, is does anybody know how to read from a .prn file in C++? Some characters may be readable, but others are junk.

Danny

Re: Reading a .prn file

normanS13-Jul-05 20:46

normanS

13-Jul-05 20:46

I did something 10 or 15 years ago, using Borland Turbo C++3, to clean up an OS-2 print file, so I could use it in DOS / Windows 3.1. The problem was that my OS-2 print-to-file contained tables, etc, which did not translate well to the Windows default character set.

As far as I remember, my approach was brute force, and it worked quite nicely! Basically, the flow was something like:

do while not EOF()<br />
   read character from file as a byte value<br />
   if character is a special character<br />
      // Deal with carriage returns, page feeds, etc<br />
      replace special character with standard character<br />
      // use a switch to deal with all the special cases<br />
   do something with character<br />
   // write to file or collect into a string or whatever<br />

Some points worth noting:
1. This is a lot easier (fewer strange characters) if you choose a really simple printer - install a Generic / Text only printer in Windows.
2. I decided how to deal with special characters by doing a simple print to a printer and the same print to a file, and comparing the print file with the paper copy. This was in DOS days, so I also had to take care of converting the PC line-drawing characters to "|", "-", "+", etc.
3. According to my flow above, it may be easiest (least change to your existing program) to create a temporary "cleaned" text file from the print file, then use the cleaned file as input to your file-to-database program.

Re: Reading a .prn file

bugDanny14-Jul-05 9:06

bugDanny

14-Jul-05 9:06

Thanx, I'll see what I can do with this. Right now, in the file, I see a bunch of those funny boxes, but maybe my program will be able to read something from them.

Yesterday is history
Tomorrow's a mystery
Today is a gift
That's why they call it the present.

Danny

Re: Reading a .prn file

normanS14-Jul-05 20:10

normanS

14-Jul-05 20:10

Good luck.

As I indicated, a key part of what I did was to read the print file byte by byte as unsigned char, identify "bad" values, and replace "bad" values with "good" values using a Switch statement.

color pallete

MSaty13-Jul-05 10:15

MSaty

13-Jul-05 10:15

i want during writing code on the vc6 editor to press a short cut and get a color picker panel and
choose one of those color so its hexadecemal code is written in the editor how can i do this
how do i add this capability to vc6 editor if it is not found ?

MSaty Bottom Up Gamer

Re: color pallete

Christian Graus13-Jul-05 12:35

Christian Graus

13-Jul-05 12:35

There is a common dialog class for the color picker that you're used to seeing. It's also possible to write your own, there are at least a couple that do HLS here on code project.

Christian Graus - Microsoft MVP - C++

Re: color pallete

MSaty14-Jul-05 23:08

MSaty

14-Jul-05 23:08

and how can i make this dialog class run in the editor of the visual studio 6 environment, i mean
while i am writing code to any program i want the dialog class to be a feature in the visual studio
environment, righ click and one of those pop up options is _ color picker _ i hope my question is
clear...;)

MSaty Bottom Up Gamer

Re: color pallete

Christian Graus17-Jul-05 12:57

Christian Graus

17-Jul-05 12:57

Well, then you'd have to write a visual studio add in. The question would be - why ?

Christian Graus - Microsoft MVP - C++

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.