C / C++ / MFC

RobJones3-Sep-03 8:16

RobJones

3-Sep-03 8:16

I was just trying to make the question simple..

I have a structure that contains chars, int's etc...

I send the structure across a socket.. when it's received on the other side I I want to put the char (from the structure) into a CString. so my question was is it ok to to do a CString strTest = sTest or should I use the format function provided by CString?

I guess I just tried to over simplify the question...

Rob

Whoever said nothing's impossible never tried slamming a revolving door!

Brad Sokol3-Sep-03 8:33

Brad Sokol

3-Sep-03 8:33

The following two lines are equivalent:

<br />
std::string s1("one");    // Example 1<br />
std::string s2 = "two";   // Example 2<br />

If I recall correctly, there is a standard "short-cut" that compilers can (must?) take to make example 2 above work like example 1. In other words, declaration with assignment is optimised to a constructor provided that an appropriatly overloaded constructor exists. If no constructor, you get a compiler error.

Either would likely be faster then default constructor followed by Format() for two reasons. First, it's two steps. Second, Format() is probably slow with all that string parsing. Of course, YMMV.

Brad

Maximilien3-Sep-03 9:07

Maximilien

3-Sep-03 9:07

will #2 generate a copy constructor ? or will it be converted into constructor ?

Maximilien Lincourt
"Never underestimate the bandwidth of a station wagon filled with backup tapes." ("Computer Networks" by Andrew S Tannenbaum )

Michael Dunn3-Sep-03 9:20

Michael Dunn

3-Sep-03 9:20

std::string s1("one"); // Example 1<br />
std::string s2 = "two"; // Example 2

Those two lines are identical. They both call a one-parameter ctor. Even though line 2 uses =, it does not call operator =

--Mike--
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Michael Dunn3-Sep-03 9:23

Michael Dunn

3-Sep-03 9:23

Format() in this case is the worse choice of the two, because it's a bit harder to read. With the plain assignment, it's clearer what the code is doing. Format() also will run a bit slower because it has to parse the format string and the other arguments in order to calculate the length of the resulting string, although the slowness is nothing a person would even notice.

--Mike--
Ericahist | Homepage | RightClick-Encrypt | 1ClickPicGrabber
Ericahist updated Aug 30!

CListCtrl custom RectTracker

David Crow3-Sep-03 10:59

David Crow

3-Sep-03 10:59

M. Dunn has the right response. If you are just assigning a simple string of characters to the CString object, using the assignment operator is the easiest. Employ the use of Format() only when variables/values need to be substituted.

Nicolas Bonamy3-Sep-03 7:32

Nicolas Bonamy

3-Sep-03 7:32

Hello,

does anyone know how to customize the look of the CListCtrl RectTracker? I want it to look like the Windows XP Explorer RectTracker and still reuse a max of stuff already implemented in the standard RectTracker provided by CListCtrl (like dynamic selection and partial invalidates)?

Regards,
Nicolas

How to prevent of access to the local files through Internet Explorer (WebBrowser ActiveX)?

Valera2411763-Sep-03 5:16

Valera241176

3-Sep-03 5:16

In MSDN I’ve found article Q179221 where it is described how to do it using Explorer Policies
(keys NoRun, NoFileUrl, NoDrives, etc under HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer). But it is not prevent, for example, of viewing end executing files in the frame: .
Is anybody ever met with such a task?

Re: How to prevent of access to the local files through Internet Explorer (WebBrowser ActiveX)?

Brian Shifrin3-Sep-03 6:53

Brian Shifrin

3-Sep-03 6:53

>Is anybody ever met with such a task?

Yeah, pretty simple. Just embed webbrowser in your own application,

OnNavigate(Navigate2) check url and cancel navigation if it is local drive.

Brian

Another transparent question

Zizilamoroso3-Sep-03 5:05

Zizilamoroso

3-Sep-03 5:05

This one is probably asked before, I saw some solutions but none of them seem to work.

How do you make a text static transparent?

I've got this:

CStatic m_ctrlLabel;<br />
m_ctrlLabel.Create(_T("TEST"), WS_VISIBLE|WS_CHILD, CRect(0,0,32,16), pParent, 0);<br />
m_ctrlLabel.ModifyStyleEx(0,WS_EX_TRANSPARENT);

But this doesn't work. Did I forget something?

btw. I'm not planning to subclass the control.

using: [VISUAL STUDIO 6.0 sp5] [WIN98/2]

Re: Another transparent question

Valera2411763-Sep-03 5:34

Valera241176

3-Sep-03 5:34

Control with WS_EX_TRANSPARENT has the background of its parent. You probably put static control on i.e tab control which lies on dialog. But the parent of static control is still this dialog. To correct such situation override CDialog::OnCtlColor. Type ON_WM_CTLCOLOR() in MESSAGE_MAP. Then
change the background color of your static control as you wish (i.e set it as those tab control):
HBRUSH CTTSDialog::OnCtlColor(CDC* pDC, CWnd* pWnd, UINT nCtlColor)
{
HBRUSH hbr = CDialog::OnCtlColor(pDC, pWnd, nCtlColor);
if (nCtlColor == CTLCOLOR_STATIC && pWnd->GetDlgCtrlID() != IDC_DEFAULT_CHECK)
{
CWnd *TabCtrl = GetDlgItem(IDC_LANG_TAB);
CWnd *Ctrl = GetDlgItem(pWnd->GetDlgCtrlID());
if (Ctrl)
{
CRect Rect; Ctrl->GetWindowRect(&Rect);
TabCtrl->ScreenToClient(&Rect);
COLORREF Clr = TabCtrl->GetDC()->GetPixel(Rect.left-1, Rect.top-1);
DeleteObject(hbr);
hbr = CreateSolidBrush(Clr);
pDC->SetBkColor(Clr);
}
}
return hbr;
}

Re: Another transparent question

Brian Shifrin3-Sep-03 7:06

Brian Shifrin

3-Sep-03 7:06

MSDN:

WS_EX_TRANSPARENT Specifies that a window created with this style is to be transparent. That is, any windows that are beneath the window are not obscured by the window. A window created with this style receives WM_PAINT messages only after all sibling windows beneath it have been updated.

In other words all WS_EX_TRANSPARENT does is changes the way WM_PAINT is sent. To make static transparent You need to override OnCtlColor and set correct dc mode.

HBRUSH CMyFormView::OnCtlColor(CDC* pDC, CWnd* pWnd, UINT nCtlColor)
{
   if (m_nWhich==ID_MY_STATIC )
   {
      pDC->SetBkMode(TRANSPARENT);
      pDC->SetTextColor(GetSysColor(COLOR_WINDOWTEXT));
   }
}

Diable enter key

NewHSKid3-Sep-03 4:45

NewHSKid

3-Sep-03 4:45

I would like to know if there is a way to disable the enter key from being used in my app. It seems that every time the enter key is pressed, it closes a dialog in my app.

Thank you.

Jimmy

Just cause I am 15, doesn't mean I'm dumb! (I'll really be 4 on Feb. 29...the year 2004)

Ravi Bhavnani3-Sep-03 5:35

Ravi Bhavnani

3-Sep-03 5:35

There are basically 2 ways to handle this.

Write a handler for OnOK() that doesn't do anything (i.e. just returns) and create another "OK" button (eg. with id IDC_REAL_OK_BUTTON) and write a handler for that, which simply calls CDialog::OnOK().
Override PreTranslateMessage() and filter out the appropriate message - I think it's WM_CHAR but I could be wrong. This will force your user to click the OK button to end the dialog.

/ravi

Let's put "civil" back in "civilization"
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ravib@ravib.com

NewHSKid3-Sep-03 5:58

NewHSKid

3-Sep-03 5:58

Thanks Ravi,

I am still new to Programming, and what you said makes sense but is still foreign to me.
Can you tell me where I would find the PreTranslateMessage() function?

Perhaps you would be kind enough to point me to some example code or some steps to which i can get this accomplished.

Thanks you.

Jimmy

Just cause I am 15, doesn't mean I'm dumb! (I'll really be 4 on Feb. 29...the year 2004)

Ravi Bhavnani3-Sep-03 6:01

Ravi Bhavnani

3-Sep-03 6:01

Search for the text "PreTranslateMessage" on this page: http://www.widgetware.com/faqsub.htm[^] and use the VK_ENTER code.

/ravi

Let's put "civil" back in "civilization"
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ravib@ravib.com

How to capture ENTER key in single line edit box?

valikac3-Sep-03 6:00

valikac

3-Sep-03 6:00

Furthermore, override OnClose().

Kuphryn

melwyn3-Sep-03 4:40

melwyn

3-Sep-03 4:40

Hi,
I have a single line edit box on a dialog. When the user finishes typing in the edit box and presses the Enter key I would like to receive notification so that I can do the required processing.
How do I get notified when the user presses the Enter key? Is my only option the PreTranslateMessage?

Thanks.

Re: How to capture ENTER key in single line edit box?

Ravi Bhavnani3-Sep-03 5:37

Ravi Bhavnani

3-Sep-03 5:37

See my reply to the next (i.e. more recent) message in this forum.

/ravi

Let's put "civil" back in "civilization"
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ravib@ravib.com

Problem with thread

Majid Shahabfar3-Sep-03 4:14

Majid Shahabfar

3-Sep-03 4:14

Hi dear,
I created a thread.
But when I start the thread CPU load become 100%.
I use these code.

void CEventLine::BeginThread()<br />
{<br />
m_isRunning = TRUE;<br />
AfxBeginThread(ThreadStart,this,THREAD_PRIORITY_LOWEST);<br />
}<br />
<br />
UINT CEventLine::ThreadStart(LPVOID pParam)<br />
{<br />
CEventLine* pEventLine = (CEventLine*)pParam;<br />
if (pEventLine == NULL || !pEventLine->IsKindOf(RUNTIME_CLASS(CEventLine)))<br />
return 1; // if pEventLine is not valid<br />
<br />
while(m_isRunning == 1)<br />
pEventLine->Start();<br />
<br />
return 0; // thread completed successfully<br />
}<br />
<br />
void CEventLine::Start()<br />
{<br />
// some code<br />
}<br />

CEventLine is a CDialog based class.
Thank you in advance.

Iain Clarke, Warrior Programmer

Iain Clarke, Warrior Programmer3-Sep-03 5:52

3-Sep-03 5:52

It's no great shock that the CPU load is 100%.
After all...

  while (m_isRunning == 1)
    pEventLine->Start ();
  ...
}

void CEventLine::Start ()
{
}

simply calls Start again and again and again... with no pause for "breath". It would be the same
if you put this code in your main thread. You have a few choices...

a) Put up with it. Assuming this is only for a brief duration.
b) Put up with it, but make it less of a nuisance. I've not used MFCs threads, and MFC is poor at sharing,
but you can lower thread priority to make other threads more responsice.

DWORD dwID;
hScanThread = ::CreateThread (NULL, 0, DoScan, this, CREATE_SUSPENDED, &dwID);
if (hScanThread == NULL)
{
  DWORD   dwError = ::GetLastError ();
} else
::SetThreadPriority (hScanThread, THREAD_PRIORITY_HIGHEST);

c) Put a delay (sleep) between each iteration of the loop. This would have to be short.
d) Some other tactic depending on the contents of CEventLine::Start ().

Iain.

Brad Sokol3-Sep-03 5:56

Brad Sokol

3-Sep-03 5:56

Choice e) might be let the thread naturally relinquish the CPU by blocking on an I/O or message queue, for example. Depending on how often/long it blocks, this may be enough.

Brad

Iain Clarke, Warrior Programmer

Iain Clarke, Warrior Programmer3-Sep-03 6:02

3-Sep-03 6:02

True, but then it may not respond to the "quit" flag.

Then again, waiting on multiple objects (the first of which is a KILL, DIE, DIE! event)
is the way I usually go. But with less dramatic variable names.

Iain