Re: Unable to get device context - C / C++ / MFC Discussion Boards

Cedric Moonen31-May-06 3:46

31-May-06 3:46

You can use your debugger to narrow the problem. The call stack is also very usefull to find which of your function caused the crash.

Cédric Moonen
Software developer

Charting control

Re: Illegal Instruction

Russell^'31-May-06 4:06

Russell^'

31-May-06 4:06

sigh:

sigh:
It cames when
CvtkInteractor::Initialize()

Probally a bad dll of the VTK toolkit

Cheers,
Russell

Unable to get device context

shivditya31-May-06 3:02

shivditya

31-May-06 3:02

I tried all what possible in VC++ , or windows to find device context
I want to start thread for engine simulation. but I have to pass the dc to my
function because it is generic class and not from mfc. what to do in this case.
or please let me know how to get view window from the generic class.
here is my code.
UINT CMy5CYLINDERView::ThreadFunc(LPVOID pParam)
{
CWnd *cwnd,*cwnd1;
cwnd1 = cwnd->GetWindow(1);
CDC* pDC = cwnd1->GetDC();
simulate* eng = (simulate*)pParam;
eng->nextpos(pDC); // program compiles on run gives access violation.
return 0;

}

void CMy5CYLINDERView::support()
{
FireCylinder();
for(int ii = 0;ii <= 3;ii++)
{
x[ii] = AfxBeginThread(ThreadFunc,(LPVOID)&engine[ii]);

}
}

|| ART OF LIVING ||

Re: Unable to get device context

Hamid_RT31-May-06 3:15

Hamid_RT

31-May-06 3:15

i think your problem is cwnd1 = cwnd->GetWindow(1); whats value cwnd(CWnd *cwnd)

whitesky

Re: Unable to get device context

Sarath C31-May-06 3:28

Sarath C

31-May-06 3:28

the reason why we are making a thread static because of to access the local resource of the class.

what u had done in the code is abosolutely wrong let me point out one of them

shivditya wrote:
CWnd *cwnd,*cwnd1;
cwnd1 = cwnd->GetWindow(1);

In the above statement, cwnd* is not an initialized pointer. so u wont anything from there.

shivditya wrote:
cwnd1 = cwnd->GetWindow(1);

This one something seems wrong. what u meant by GetWindow(1)?

it is better u pass this pointer the the function or make it accesseble trough some global static pointers.
i.e
static pszWindow; // declare as static member variable
static CMy5CYLINDERView::pszWindow = NULL; // initialize it globally

on Initial update, update this value with this pointer. then u can access it at the thread function

CMy5CYLINDERView::pszWindow->GetDC();

there is one more option.

define a structure that contains all information u need at thread

the definition may goes like this

typedef struct
{
CMy5CYLINDERView* pView;
Engine* pData;
}MyThreadParam;

now u "allocate memroy" (dont pass local variable) for the type of structure and fill with required informatio and pass to the thread param

at thread function type cast and use it.

Sa^Rath

"D on't blindly follow rules you read somewhere without verifying that it makes sense for your situation!"

Re: Unable to get device context

shivditya1-Jun-06 20:10

shivditya

1-Jun-06 20:10

static CMy5CYLINDERView::pszWindow = NULL; // initialize it globally

on Initial update, update this value with this pointer. then u can access it at the thread function

CMy5CYLINDERView::pszWindow->GetDC();
there is one more option.
define a structure that contains all information u need at thread
the definition may goes like this

This highlighted line gives error as pszwindow is not object of CDC
its really problem beacause this thread function is static and it restricts a lot

|| ART OF LIVING ||

Re: Unable to get device context

eli1502197931-May-06 4:26

eli15021979

31-May-06 4:26

shivditya wrote:
CWnd *cwnd,*cwnd1;
cwnd1 = cwnd->GetWindow(1);
CDC* pDC = cwnd1->GetDC();

You are using cwnd but it was never initialized....
The DC of which window do you want to get?
Is eng is part of that window?
If so , try using this code:

UINT CMy5CYLINDERView::ThreadFunc(LPVOID pParam)
{
   YourWindow *wnd = (YourWindow *)pParam;// You should pass   the handle of the window as pParam 
   CDC* pDC = wnd->GetDC();
   wnd->eng->nextpos(pDC);
   return 0;

}

With best regards,
Eli

Re: Unable to get device context

shivditya1-Jun-06 20:21

shivditya

1-Jun-06 20:21

YourWindow *wnd = (YourWindow *)pParam;// You should pass the handle of the window as pParam

Here what means YourWindow

Beacuse I am able to get the active window I am not able to get device context.
will you please explain me what you mean by your window.

I tried long journey of HWND hwnd = :: GetActiveWindow()
then CDC tempdc = (CDC*)( ::GetWindowDC(hwnd));
but it also proved hopeless.

|| ART OF LIVING ||

Problem With MSOutLook 2003 when using Mapi

narayanagvs31-May-06 2:51

narayanagvs

31-May-06 2:51

Hi
I am popping a default mail client with an attachment for sending the mail in my application.I used a dll which inturn used Mapi.I could successfully popup the default mail client when Eudora,Outlook express are set as default mail clients but when i set MSOutLook 2003 as default i could not.

Any Suggestions or links would be useful for me.

Thanx

CreateEx and Popup window

includeh1031-May-06 2:47

includeh10

31-May-06 2:47

A CWnd based class creates a popup window:

BOOL b=CreateEx(0,0,0,WS_POPUP|CHILD,rc,pMum,100);

in XP, the call failed, by in 98 and other OS, the call is OK.

how to solve the problem for XP?

Re: CreateEx and Popup window

Hamid_RT31-May-06 2:52

Hamid_RT

31-May-06 2:52

Can you be more specific do you get error

whitesky

Re: CreateEx and Popup window

includeh1031-May-06 2:56

includeh10

31-May-06 2:56

return null.

Re: CreateEx and Popup window

Hamid_RT31-May-06 3:10

Hamid_RT

31-May-06 3:10

BOOL o=CWnd::CreateEx(0, AfxRegisterWndClass(0), "CTest1", WS_POPUP, 0,0,0,0, NULL, 0);//return 1

whitesky

Re: CreateEx and Popup window

Gautam Jain31-May-06 3:22

Gautam Jain

31-May-06 3:22

WS_POPUP and WS_CHILD flags do not go together. Only pass WS_POPUP with valid parent window handle.

GJ

Re: CreateEx and Popup window

includeh1031-May-06 3:32

includeh10

31-May-06 3:32

none of them work.

Port forwarding

Girish60131-May-06 2:40

Girish601

31-May-06 2:40

Hi friends,

we try to use port forwarding concept in our application. freinds is their any software for port forwarding is available , so that we will use it in our application. or any sample code for port forwarding is available , so we will study that code and try to use in our application. If any links regarding port forwarding is ezists , provide us. frinds kindly give us reply.

regards

Girish
Software Developer

Re: Port forwarding

sunit531-May-06 4:56

sunit5

31-May-06 4:56

Port forwording is done by firewall automatically(u have to write rules).So what is ur purpose.

never say die

How to place an edit box and dialog box on a window(SDI,MFC based application))in VC++ dot Net-2003 version

Ashutosh Bagaria31-May-06 2:39

Ashutosh Bagaria

31-May-06 2:39

Hi,
I request u to kindly ans :
"How to place an edit box and dialog box on a window(SDI)( Smile | :)

MFC based application)in VC++ dot Net-2003 version".
Thank you very much. Smile | :)

Re: How to place an edit box and dialog box on a window(SDI,MFC based application))in VC++ dot Net-2003 version

Sebastian Schneider31-May-06 4:14

Sebastian Schneider

31-May-06 4:14

Change to Resource View, then change into the Dialog-Folder and edit the Dialog.

--
Contra vim mortem non est medicamen in hortem.

Hadi Dayvary31-May-06 2:20

Hadi Dayvary

31-May-06 2:20

Hi How can I get HWND from a process HANDLE?

Re: Hi

ThatsAlok31-May-06 2:28

ThatsAlok

31-May-06 2:28

Hadi Dayvary wrote:
Hi
How can I get HWND from a process HANDLE?

You have to Enumerate all window on desktop and compare each Processs handle to that Enumerated Window Process Handle!

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow

cheers,
Alok Gupta
VC Forum Q&A :- I/ IV
Support CRY- Child Relief and You

Re: Hi

Hadi Dayvary31-May-06 2:37

Hadi Dayvary

31-May-06 2:37

So how to get process HANDLE from a HWND?

Re: Hi

David Crow31-May-06 5:18

David Crow

31-May-06 5:18

Hadi Dayvary wrote:
So how to get process HANDLE from a HWND?

How about GetWindowThreadProcessId()?

"The largest fire starts but with the smallest spark." - David Crow

Re: Hi

NiceNaidu31-May-06 2:35

NiceNaidu

31-May-06 2:35

Use the following code

BOOL CALLBACK EnumWindowsProc(HWND hWnd, LPARAM lParam)<br />
{<br />
EnumInfo info;<br />
DWORD pid;<br />
EnumWin * enumWin =<br />
reinterpret_cast(lParam);<br />
GetWindowThreadProcessId(hWnd, &pid);<br />
<br />
if (pid == enumWin->m_pid)<br />
{<br />
if(GetParent( hWnd ) == 0)<br />
{<br />
enumWin->m_found = TRUE;<br />
enumWin->m_hwnd = hWnd;<br />
AfxMessageBox("handle found!");<br />
return FALSE; <br />
// once found a matching HWND stop enum<br />
}<br />
}<br />
return TRUE; //keep on it<br />
}

you can use WaitForInputIdle(...) for the process to finish initializing before you try to find its HWND. this will not work with apps that start with a process and switch to another while excuting (e.g. mozilla fire fox).

Appu..
"If you judge people, you have no time to love them."

Rotating entire application

Andrew JM Hall31-May-06 2:20

Andrew JM Hall

31-May-06 2:20

I have an issue that requires either the rotation of the application (MFC Doc/View architecture - yes i know but it's a legacy application) or the screen (ATI Radeon). I've tried using the ChangeDisplaySettings API call (it does this already to set the required resolution, and yes I know this is a bad thing generally but this project requires the switching of two legacy applications both of which are EPoS and the operator is trained and paid to put up with it) and setting the rotation flag to DM_180 but I always get a DISP_CHANGE_BADMODE.

So I have a display on a hinge, and one application (the doc/view one) ends up being upside down. The ATI card has a tray application which lets the display be flipped, but I can't how to do it using API calls, or even calling into an ATI dll. (The ATI card isn't guaranteed to be used throughout the life of the project, it could well be replaced by another make/model). Unless some clever person out there can tell me how to rotate the display programically, the only other way is to add some code so that the output of the doc/view application is inverted.

Does anyone have any ideas?

Andy

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