Re: Modeless dialog box in a thread

From:

Ajay Kalra <ajaykalra@yahoo.com>

Newsgroups:

microsoft.public.vc.mfc

Date:

26 Apr 2007 21:03:06 -0700

Message-ID:

<1177646586.598418.47410@t38g2000prd.googlegroups.com>

Why do you need a separate thread for your dialog? There is almost
never a need for this. Your dialog should be in main gui thread.

---
Ajay

On Apr 26, 3:44 pm, Punit Kaur <PunitK...@discussions.microsoft.com>
wrote:

Hi,

I have a multi-threaded application. In the application there is a class
CDiskSpaceWarn corresponding to a modeless dialog box that I need to create
in DiskSpaceCheck thread which is spawned in the Application main dialog's
Oninitdialog method.

Here is the definition of the thread:

        UINT ThreadDiskSpaceWarn(LPVOID pvoid)
{
        extern CDiskSpaceWarn *pdlg;
        long unsigned int timer=0;
        ULARGE_INTEGER ll,pp,oo;
        pdlg = new CDiskSpaceWarn;

        GetDiskFreeSpaceEx(NULL,&ll,&pp,&oo);
        float fDiskNum= (static_cast<float>(static_cast<__int64>(oo.QuadPart /(1024
* 1024))))/1000;

        for(int i=0;1==1;++i)
        {
                                if(fDiskNum<20.0)
                                {
                                          pdlg->Create(IDD_DISKSPACEWARN,AfxGetApp()->m_pMainWnd);
                                        pdlg->ShowWindow(SW_SHOW);
                                        pdlg->CenterWindow(NULL);
                                        pdlg->RunModalLoop();
                                }
                        Sleep(3600000);
                        if(!threadDiskSpaceWarn) //Closing?
                                break;
        }

        return(0);

}

The EndDialog menthod for this modeless dialog is overridden as follows:

void CDiskSpaceWarn::OnOK()
{
        // TODO: Add extra validation here
        pdlg->EndModalLoop(100);

        pdlg->DestroyWindow();

        CDialog::OnOK();

}

The thread is doing nothing but checking the hard diskps space every one hr
and brings up a modeless dialogbox incase the diskspace is less than 20GB. It
works well in the Release mode. But it throws an assertion error in Debug
mode. I read somewhere that it is not a right way to use Main windows handle
in worker threads. Could you please tell me how to go about it.?

I need to fix this asap.
Thanks