How to create a dialog from thread

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Hello Friends,

I am new to VC++ environment. Here my job was to create a dialog from the thread and to be plotted on to the child dialog. Here I'm posting a pseudo code.

In file Sched.cpp

extern CPaint *m_dlg;
void CSched:: Minor()
{
   CWinThread *pThread = NULL;
   pThread = AfxBeginThread((AFX_THREADPROC)CallGraph,NULL);
   if(pThread == NULL)
      MessageBox("Thread Fails");
}

UINT CShed::CallGraph(LPVOID pParam) 
{
   m_dlg -> StartGraph();
   return TRUE;
}

In another file Paint.cpp

void CPaint::StartGraph()
{
   CPaint *m_dlg;
   m_dlg = new CPaint();
   m_dlg->Create(IDD_PAINT_DLG,NULL);
   m_dlg->ShowWindow(SW_SHOW);
}

Please reply as soon as possible. I am not getting what mistake is there in this code but I am sure that the program is compiling and thread is created and dialog is not created.

Thank you in advance

Posted 9-May-10 17:39pm

pra84veen

Updated 10-May-10 1:29am

Moak

v4

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ThatsAlok 4-Jul-11 3:10am

where are you giving memory to extern variable m_dlg

5 solutions

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Michel Godfroid · Answer 1 · 2010-05-10T02:10:00

Solution 1

Excuse me for stating the bleeding obvious, but do you have a message loop somewhere in your program?

Posted 10-May-10 2:10am

Michel Godfroid

Comments

Albert Holguin 3-Jul-11 23:16pm

OP said (in deleted solution):
Hello Michel..

I dint get what u r telling...Message looping means??..

ThatsAlok 4-Jul-11 3:12am

when you create dialog box in MFC, it will provide you defualt messsage loop? so that not a question!

XTL_FANS · Answer 2 · 2010-05-12T20:07:00

Solution 3

Please read the multithread GUI source code within WTL。

Posted 12-May-10 20:07pm

XTL_FANS

**ThatsAlok** · Answer 3 · 2011-07-03T21:22:00

Solution 5

Agreed with albert, you can't have modeless dialog box within thread which is terminating after creation of dialog!

Posted 3-Jul-11 21:22pm

ThatsAlok

**ThatsAlok** · Answer 4 · 2011-07-03T21:27:00

in addtion to my solution, you can keep it running by adding window message loop to your thread, some thing like this :-

C#

MSG lpmdg;
    while(GetMessage(&lpmdg,0,0,0))
    {
        DispatchMessage(&lpmdg);

    }

i forget, how to handle dialog close here, but let you know how to do that!

Albert Holguin · Answer 5 · 2011-07-03T17:15:00

Solution 4

Check to see if there's any errors being returned from the Create() method when you try to create the dialog. There may also be an issue with creating a modeless dialog on a thread that just ends right after creating the dialog.

Posted 3-Jul-11 17:15pm

Albert Holguin