|
Why would my CDBConnection->m_pErrorInfo be NULL after I have purposely entered an incorrect password?
Thanks,
Chris
|
|
|
|
|
Hi all,
I have written an MFC application with standard controls. But I realized that at resizing the window, the whole window flicker.
I saw that there are a lot of posting on flicker-free app in here already. But since I am not writing any fancy graphics object, I am thinking if there is a way of doing double buffering (one way of removing flickering) without having to manipulate deeply on the OnDraw() function.
I tried the Keith Rule's CMemDC object in my own derived view and override the OnDraw () to be
{
CRect bounds;
CRect lBounds;
GetClientRect(&bounds);
lBounds = bounds;
CMemDC pDC(dc, &lBounds);
CFormView::OnDraw(pDC); //CFormView is my parent
}
But on resizing, the app still flicker.
Any suggestion?
Thanks a lot,
Jimmy Chu
|
|
|
|
|
Check if you window class has CS_HREDRAW or CS_VREDRAW style if it has, remove them
Edward
|
|
|
|
|
You can reduce the amount of flickering by handling the WM_ERASEBKGND message. I usually do it like this:
BOOL CCommunicationView::OnEraseBkgnd(CDC* pDC)
{
static int dont_erase_indexes[] =
{
IDC_DPAS_LAMP,
IDC_INSTRUMENT_TYPE,
IDC_LABEL1,
IDC_LABEL2,
IDC_DESTINATION,
IDC_CURRENT_STATUS,
IDC_LOG,
IDC_GRAPH,
IDC_DOWNLOAD_STATUS,
IDC_DOWNLOAD_PROGRESS,
ID_AUTO_LOAD,
IDC_UPLOAD_ASSAYS,
IDC_AUTO_UPLOAD,
IDC_BROWSE_FOR_FOLDER,
IDC_AUTOREFINE_GRAPH,
IDC_DIRECT_CONTROL_STATUS,
IDC_ABORT_ASSAY
};
CRect clip;
pDC->SaveDC();
for (int i = 0; i < sizeof(dont_erase_indexes) / sizeof(int); i++)
{
CWnd *pWnd = GetDlgItem(dont_erase_indexes[i]);
if (pWnd && pWnd->IsWindowVisible())
{
pWnd->GetWindowRect(&clip);
ScreenToClient(&clip);
pDC->ExcludeClipRect(&clip);
}
}
pDC->GetClipBox(&clip);
pDC->FillSolidRect(clip, GetSysColor(COLOR_BTNFACE));
pDC->RestoreDC(-1);
return FALSE;
}
Roger Allen - Sonork 100.10016
Roger Wright: Remember to buckle up, please, and encourage your friends to do the same. It's not just about saving your life, but saving the quality of life for those you may leave behind...
|
|
|
|
|
is it possible to make a complete windows program in visual basic c++ i have only just started learning this and was wondering just what you can do with it also does ne one know of any sites that can give me lots of info to help me plz cheers, or would borland be better
|
|
|
|
|
It is possible to make programs with both Visual Basic and Visual C++. The C++ version is harder to learn, but gives much greater degree of control over the applications you create and over your system.
VB, on the other hand, is much quicker to learn, but when you need to do something more difficult like customize a Windows control, it starts to run out of options.
For a good book, try to find a one with 'Learn yourself Visual C++ in xx days'. They are easy to understand, quick and effective. However, if you have no prior experience in C/C++, I suggest getting a decent book from this area first and reading it. Understanding and mastering C/C++ is the key in being a succesfull programmer for Visual C++.
-Antti Keskinen
----------------------------------------------
The definition of impossible is strictly dependant
on what we think is possible.
|
|
|
|
|
I think you're a bit too confused ... 
are you talking about C++ or visual basic ?
Maximilien Lincourt
Your Head A Splode - Strong Bad
|
|
|
|
|
It is quite possible to build complete Windows applications using either tool, Visual Basic or Visual C++. That's what they were designed to do. VC++ is harder to learn, but it also offers far more control over the target platform. VB is simple to learn, but it hides much of the detail from you and makes it simple to fall into sloppy coding habits. Borland has made excellent products in the past, but I haven't used any of them in 10 years or so. Which product you use is a matter of personal taste, but I suspect that you'll have fewer hassles using products made for Windows programming by the folks who make Windows.
As for sites that offer assistance and code samples, you can't do better than this one. Pick a language and start reading through the articles under that heading. You would also be well advised to pick up a couple of books on the language you choose to learn. Microsoft documentation is adequate for reference and quite complete, but it's useless and overwhelming for learning.
Heard in Bullhead City - "You haven't lost your girl -
you've just lost your turn..." [sigh] So true...
|
|
|
|
|
Most excellent synopsis by Antti and Roger 
May I add one thing. If you are wanting to learn Visual C++ ... It would probably do you well to pick up a book about "What is OOP" or "Understanding OOP" (OOP = Object Oriented Programming) C++ is an object orientated language so in order to do a lot of things that you'll want to do when you create a Windows app, you will need to understand what object oriented programming is all about!
shultas
|
|
|
|
|
I'm wanting to implement PNG file loading in a C++ like Photoshop .8bf plugin development language (FilterMeister). This language has no support for functions, linked-libraries, advanced file manipulation...
I'm trying to find sourcecode for a PNG loader in C/C++ but the best I've found is hazy details on the zlib site. Not being a real coder I need a link to an actual example that I can work from, instead of definitions and technical details.
Thanks for any help,
Shifty Geezer
...
|
|
|
|
|
I'm having trouble linking a CVF subroutine with my VC++ source code. I have the declarations in place and can successfully compile, but when I link, I get the following error -
error LNK2001: unresolved external symbol "void __cdecl LSQFIT(float *,float *,int *,int *)" (?LSQFIT@@$$J0YAXPAM0PAH1@Z)
My source and external subroutine are below -
extern "C" void LSQFIT(float*xp, float*fxp, int*nx, int*maxord);
int main()
{
float fxp[1000],xp[1000];
int maxord[1],nx[1];
*nx = 10;
*maxord = 3;
LSQFIT(xp,fxp,nx,maxord);
....
CVF subroutine -
SUBROUTINE LSQFIT(XP,FXP,NX,MAXORD)
DIMENSION XP(1),FXP(1),COEFF(11),ERR(10)
|
|
|
|
|
While I might be wrong, I'm pretty sure that your main and function declation are in C.
SUBROUTINE LSQFIT(XP,FXP,NX,MAXORD)
DIMENSION XP(1),FXP(1),COEFF(11),ERR(10)
Looks awfully like it is in FORTRAN... While it may be theoretically possible to link the
two, it's very hard at the least. It's bad enough mixing C and C++...
You'd be better looking for a C implementation, or porting the algorithm from Fortan to C.
Iain.
|
|
|
|
|
I am writing an application in MFC. What I am trying to do is see every internet packet that is being recieved or sent through my computer. I am assuming that I am going to need to use Winsock? Other than that, I have no clue, so any help is appreciated.
-Dev578
|
|
|
|
|
|
or check out EtherPeek at http://www.wildpackets.com/[^]
it does cost $$$ but if you are going to do a lot of it, it's completely worth it.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~<br />
Peter Weyzen<br />
Staff Engineer<br />
<A HREF="http://www.santacruznetworks.com">Santa Cruz Networks</A>
|
|
|
|
|
I highly recommend Network Programming for Microsoft Windows, Second Edition by Anthony Jones and Jim Ohmund.
Kuphryn
|
|
|
|
|
Check out microsoft's layered service provider sample from platform sdk (used to be in netds\winsock\lsp) and this also could be helpful http://www.microsoft.com/msj/0599/LayeredService/LayeredService.aspx
Edward
|
|
|
|
|
Hello !
I am beginner in C++ and i need some help from you !
I want to make my console program into windows application,
but I dont now how to do it. Please help me !
Thank you.
Boco 
//PROGRAM FOR CALCULATING SUM AND AVERAGE OF TWO NUMBERS
#include
#include
int main ()
{
float num_1, num_2;
double sum, average;
cout << "\n\t\t******************************************* ";
cout << "\n\t\t* PROGRAM FOR CALCULATING SUM AND AVERAGE * ";
cout << "\n\t\t* OF TWO NUMBERS * ";
cout << "\n\t\t* Version 1.0, February, 2004 * ";
cout << "\n\t\t******************************************* ";
cout << "\n\n\n\n\n Enter first number: ";
cin >> num_1;
cout << "\n Enter second number: ";
cin >> num_2;
sum = num_1 + num_2;
average = sum / 2.0;
cout << "\n\n Calculated sum is: " << sum << endl;
cout << "\n Calculated average is: " << average << endl;
cout << "\n\n\n\n\n For exit from program press [Enter] >>>>> ";
getchar();
return (0);
}
|
|
|
|
|
Reposting won't get you an answer any faster.
A Windows application needs to be structured very differently from a console application. You respond to events from the operating system, rather than driving the process yourself. You need, at the very least, to create a window with suitable controls, then start up a message loop. Frameworks such as MFC can provide a lot of the boilerplate code for you.
There isn't space to go into it here, and there are many resources. Try for example Programming Windows by Charles Petzold, Programming Windows with MFC by Jeff Prosise, or for a simpler reference, try Teach Yourself MFC in 24 Hours from SAMS.
I would recommend an MFC dialog-based application, with two edit boxes for the two numbers, static controls for the results, and a Calculate button. You would then perform your calculations and show the results in a BN_CLICKED handler for the button. Alternatively you could simply handle EN_CHANGE on both the edit fields and compute the results as the user types. It's up to you.
|
|
|
|
|
Mike, that sounds very havy, do you have maybe same
example like my program is ?
Boco
|
|
|
|
|
Send me a mail so i can send u the program
Papa
while (TRUE)
Papa.WillLove ( Bebe ) ;
|
|
|
|
|
Hi All,
I want to write an application which should display a pdf file, and some other features like searching,highlight text,zoom etc. Is there any free/paid controls available. I tried using pdf.ocx but it's very slow and also not feature for searching, highlight text etc. Any idea how to do this ?
Thanks
Mahesh Varma.
|
|
|
|
|
We investigating XpdfViewer by Glyph and Cog at http://www.glyphandcog.com
--
Joel Lucsy
|
|
|
|
|
Hello guys,
during debugging the compiler gives this memory leak warning messages. Due to my lack of knowledge, I am not able to find which lines (parts) of the codes causing the memory leak, by telling from the messages.
Detected memory leaks!
Dumping objects ->
{161} normal block at 0x00C86988, 25 bytes long.
Data: <` l > 60 C0 6C 00 08 00 00 00 08 00 00 00 01 00 00 00
{84} normal block at 0x00C867A0, 51 bytes long.
Data: <` l " " > 60 C0 6C 00 22 00 00 00 22 00 00 00 01 00 00 00
{78} normal block at 0x00C86618, 40 bytes long.
Data: <g > 67 00 00 00 D3 01 00 00 00 00 00 00 00 00 00 00
Object dump complete.
Can anyone help?
|
|
|
|
|
The memory leaks are pretty small by size, this suggests that the unfreed objects are some small or tiny variables. Try double-checking your source files that for each memory reserving call (new or malloc) you call the respective deletion call (delete or free).
The final option is to run the debugger, copy each new reserved memory's pointer's target address into paper and then compare these with the posted object addresses. This is tedious and long-term work but allows you to pinpoint what pointers are not freed properly.
Remember that the most common cause for these problems is that you have an object that reserves memory dynamically in it's constructor, but does not free it in the destructor or during it's life cycle. Once again, check your code.
Alternatively, if you have money to spare, try investing into some memory-validation program, which are available through CodeProject partners as well. There are many available, and they don't even cost too much.
-Antti Keskinen
----------------------------------------------
The definition of impossible is strictly dependant
on what we think is possible.
|
|
|
|
|
General 
News 
Suggestion 
Question 
Bug 
Answer 
Joke 
Praise 
Rant 
Admin 
Submit an article or tip
