C / C++ / MFC Discussion Boards

Re: "Assertion Failed" with thread and device context

nautilusvn29-Jul-09 17:25

nautilusvn

29-Jul-09 17:25

Thank Richard,

I have followed as your advise and the Debugger points to this line of my code:

Ellipse(hdc, p->x - temp, p->y - temp, p->x + temp, p->y + temp);

It says "Access violation".

I guess that it has some conflict between threads on the device context I've used. But I don't know how to solve it.
Please help!

Re: "Assertion Failed" with thread and device context

Richard Andrew x6429-Jul-09 17:31

Richard Andrew x64

29-Jul-09 17:31

When you debug it, inspect the variable "p" to be sure that it points to a valid object.

That may be the source of the access violation.

Re: "Assertion Failed" with thread and device context

Richard Andrew x6429-Jul-09 17:35

Richard Andrew x64

29-Jul-09 17:35

I failed to notice something serious:

You're trying to draw in the window with a secondary thread.

This is not allowed in MFC.

You must do all your drawing with the same thread that owns the window.

Re: "Assertion Failed" with thread and device context

nautilusvn29-Jul-09 20:27

nautilusvn

29-Jul-09 20:27

Thank Richard,

I greatly appreciate your help to me.

But now I'm completely surprised that drawing in the window with a secondary thread is not allowed in MFC.

Actually I'm writing a simple game, when my user selects an object on screen, I want my user take focus on that object by a moving circle around it. How people do that with MFC?

Thank

Re: "Assertion Failed" with thread and device context

Richard Andrew x6430-Jul-09 4:14

Richard Andrew x64

30-Jul-09 4:14

One way of doing it is to send a message to your window, and then handle the message in your WndProc function by drawing in the window.

See this article in MSDN. It describes the problem I mentioned:

http://msdn.microsoft.com/en-us/library/h14y172e(VS.80).aspx[^]

Re: "Assertion Failed" with thread and device context

krmed30-Jul-09 6:53

krmed

30-Jul-09 6:53

One thing I see that could also be part of your problem is that you do a GetDC() in your thread, and then you properly select the new pen, use it, select the old pen and delete it, but I don't see anywhere that you do a ReleaseDC().

This probably isn't the entire problem, but you should always release the DC after you use it that way.

Hope that helps.

Karl - WK5M
PP-ASEL-IA (N43CS)
PGP Key: 0xDB02E193
PGP Key Fingerprint: 8F06 5A2E 2735 892B 821C 871A 0411 94EA DB02 E193

Passing multi-dimensional array from C# to Win32 C++ dll? [modified] [MOVED TO C++/CLI]

devvvy29-Jul-09 16:03

devvvy

29-Jul-09 16:03

[moved to C++/CLI forum]

dev

modified on Wednesday, July 29, 2009 10:51 PM

Re: Passing multi-dimensional array from C# to Win32 C++ dll?

Richard Andrew x6429-Jul-09 16:48

Richard Andrew x64

29-Jul-09 16:48

You might have better luck posting this question in the C++/CLI forum.

error C1083

shabbychic29-Jul-09 15:57

shabbychic

29-Jul-09 15:57

When I compile my program, this is the error I get:

Compiling...
test proj.cpp
c:\program files\microsoft visual studio 8\vc\include\time.h(6) : fatal error C1083: Cannot open include file: 'stdafx.h': No such file or directory

it is a simple program without any errors, is there anyone that knows how I can fix this?

Re: error C1083

Richard Andrew x6429-Jul-09 16:47

Richard Andrew x64

29-Jul-09 16:47

Easiest fix would be to create a new header file in your project called "stdafx.h".

You could make it blank, just as long as it is there.

how to link a radio button to a command button? (mfc c++)

Neil Jigger29-Jul-09 15:06

Neil Jigger

29-Jul-09 15:06

good day,

here is my problem on how to link the commandbutton to radio buttons (mfc) in c++:

i inserted 3 radiobuttons inside a groupbox with a caption "Mode of payments";

radio1 with a caption "1. Cash (10% discount)";
radio2 with a caption "2. Two payments (5 % interest)";
radio3 with a caption "3. Three payments (10% interest);

i also have two editboxes; editbox1 and editbox2.

1. with a static text "enter tuition fee:" value will be accepted in the first editbox.
2. with a static text "Your total tuition fee is:" will be displayed in the second editbox.

and one command button with a caption "Compute"

supposing i will select the second radio button which is "two payments (5% interest)" upon clicking
the command button "compute" the result should be displayed in the second editbox under "your total tuition
fee:" which is the computation on the value of the first editbox and on the second radiobutton and so on...

if i will not use a commandbutton "compute" caption (to do the calculation) i can do the code and get the right result by
calculating the value of the first editbox and on the radiobutton values, but when i will use commandbutton to do
the calculation on the value of the first editbox to the radiobuttons that is now my problem since i cannot link the radiobuttons
and the commandbutton...

Please anybody help me in solving this problem...i need sample code as guide in solving this problem and on my future related
projects...

code experts please help me...

thank again and thank you in advance...

neil

Re: how to link a radio button to a command button? (mfc c++)

Richard Andrew x6429-Jul-09 15:45

Richard Andrew x64

29-Jul-09 15:45

Could you please restate more clearly what it is you want to do?

Do you want it to calculate the answer without having to click on the button?

Re: how to link a radio button to a command button? (mfc c++)

Neil Jigger29-Jul-09 15:48

Neil Jigger

29-Jul-09 15:48

i will select first on one of the radio buttons then by clicking on the command button which has a caption "compute" c++ will give an answer and it will be displayed in the second editbox.

Re: how to link a radio button to a command button? (mfc c++)

Richard Andrew x6429-Jul-09 16:00

Richard Andrew x64

29-Jul-09 16:00

So you want it to give a different answer depending upon which radio button is chosen?

Re: how to link a radio button to a command button? (mfc c++)

Neil Jigger29-Jul-09 16:08

Neil Jigger

29-Jul-09 16:08

yes sir if supposing i will select the first radio button which is "cash (10 % discount)" the calculated amount is the amount of the "enter tuition fee editbox1" * .90 since 10% will be deducted to the tuition fee. If radiobutton2 is selected "two payments (5% interest)" the calculated amount is the amount of the "enter tuition fee editbox1" + 5% interest. Please sir help me on this problem.

neil

Re: how to link a radio button to a command button? (mfc c++)

Richard Andrew x6429-Jul-09 16:13

Richard Andrew x64

29-Jul-09 16:13

All you have to do is use the GetCheck() function:

if ( radiobutton1.GetCheck() == BST_CHECKED )
{
   // First radio button chosen
}

if ( radiobutton2.GetCheck() == BST_CHECKED )
{
   // Second radio button chosen
}

Re: how to link a radio button to a command button? (mfc c++)

Neil Jigger29-Jul-09 16:17

Neil Jigger

29-Jul-09 16:17

i will try this one sir...thank you very much for the help

neil

Re: how to link a radio button to a command button? (mfc c++)

Neil Jigger29-Jul-09 18:38

Neil Jigger

29-Jul-09 18:38

<big>thank you very much</big> chard your code solve my problem. I posted this problem because i dont have the sample code on how to connect the radiobutton to the command button. Spider and chandru never gave me the sample code to solve my problem.

here is now my code in c++

void CTuition1Dlg::OnButton1()

{
     // TODO: Add your control notification handler code here
     UpdateData();
     if ( m_button1.GetCheck() == BST_CHECKED )
     {
             m_edit2 = m_edit1 * .9;
          UpdateData(false);
     }
     if ( m_button2.GetCheck() == BST_CHECKED )
     {
          double x;
             x = m_edit1 * .05;
          m_edit2 = m_edit1 + x;
          UpdateData(false);
     }
     if ( m_button3.GetCheck() == BST_CHECKED )
     {
             double x;
          x = m_edit1 * .10;
          m_edit2 = m_edit1 + x;
          UpdateData(false);
     }
     UpdateData(false);
}

if its not for your code I cannot solve it...thank you very much
do you have ym sir chard?
i would like to ym you if i have a problem on programming and i wish that you will still help me.

Once again thank you...

neil

LPTSTR concatenation

akhanal29-Jul-09 10:20

akhanal

29-Jul-09 10:20

Hi all,

I am converting two floats to LPTSTR and trying to concatenate them. I have tried _tcscat, StringCbCatW, lstrcat, and lstrcatW. With all of these methods, after concatenation, I am only getting the value in "message" but not the concatenated part of "message1". And the application that uses this file (dll) crashes after showing the first part.

Can someone please suggest something? Any help is appreciated.

Here is a part of the code:

float a = 45.670;
float b = 2323.78;
LPTSTR message = TEXT("");
LPTSTR message1 = TEXT("");

std::stringstream sstr;
sstr << a;
std::string str1 = sstr.str();
message = (LPTSTR)str1.c_str();

std::stringstream sstr1;
sstr1 << b;
std::string str2 = sstr1.str();
message1 = (LPTSTR)str2.c_str();

_tcscat(message,message1);
//StringCbCatW(message,BUFSIZE,message1);
//lpvMessage = lstrcatW(message,message1);

Re: LPTSTR concatenation

David Crow29-Jul-09 10:50

David Crow

29-Jul-09 10:50

akhanal wrote:
And the application that uses this file (dll) crashes after showing the first part.

Can someone please suggest something? Any help is appreciated.

Because message does not point to any allocated memory that is large enough. Why not do something like:

float a = 45.670;
float b = 2323.78;
 
std::stringstream sstr1;
sstr1 << a;
 
std::stringstream sstr2;
sstr2 << b;
 
std::string str = sstr1.str() + sstr2.str();

"Old age is like a bank account. You withdraw later in life what you have deposited along the way." - Unknown

"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons

Re: LPTSTR concatenation

akhanal29-Jul-09 11:18

akhanal

29-Jul-09 11:18

That was great, it worked.

Thanks, appreciate your help.

LIBC.lib(crt0.obj) : error LNK2019: unresolved external symbol _main referenced in function _mainCRTStartup

stephen.hazel29-Jul-09 10:14

stephen.hazel

29-Jul-09 10:14

I'm using a custom entry point.
instead of winMainCRTStartup=>WinMain, I'm using my own AppBoot().

Too make the exe a little leaner.

I've got custom new and delete and don't use exceptions.

That's all great.

But when I start using double and math funcs like sin(),
I get the above error.

my linker subsystem is windows and I have a custom entry point.

So I'm guessing one or some of the math funcs are pulling in mainCRTStartup??

Not sure why it'd pull that instead of the WinMainCRTStartup??

Anybody run into this before?

Thanks,

...Steve

Question about Boost::Regex library

msn9229-Jul-09 8:47

msn92

29-Jul-09 8:47

Hi.

I want to name subgroups in regex:
For example, if I would use .Net it would be like this:

using namespace System::Text::RegularExpressions;
...
Regex^ re="(?<letters>[a-zA-Z]*)(?<numbers>[0-9]*)";//subgroup#1 called "letters",
                                                    //subgroup#2 called "numbers"

MatchCollection^ matches = re->Matches(szInput);//szInput contains text that needs to be parsed.
for each (Match^ match in matches){
  MessageBox::Show(Match->Groups["letters"]->Value);
  MessageBox::Show(Match->Groups["numbers"]->Value)
}

Can I do the same thing in MFC using Boost::Regex libraries?

How can I show my dialog on the TOP from other window dialog?

THAQCD29-Jul-09 7:38

THAQCD

29-Jul-09 7:38

I try to use Modal & Modeless dialog to show WARNING within 2 seconds as the following:
CDialog *dlg;

dlg = new CDialog;
int id = dlg->Create(IDD_DIALOG_MESSAGE, this);
dlg->ShowWindow(SW_SHOW);
//dlg->SetParent(this);
Sleep(2000);
dlg->DestroyWindow();

But it always appearing under the other Window dialog, even I remove the comment out as parent, but it doesn't help

Any one know how to do it?

Re: How can I show my dialog on the TOP from other window dialog?

Code-o-mat29-Jul-09 9:35

Code-o-mat

29-Jul-09 9:35

Try with BringWindowToTop[^]. However, freezing your GUI thread for 2 seconds (leaving it completely unresponsive and undrawn) isn't such a good idea, you could try bringing your window up and then removing it later using a timer (WM_TIMER)...anyways, if you insist on the sleep you might need to explicitly redraw [^] your warning window before the sleep.

> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Life: great graphics, but the gameplay sux. <

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