How to show a modal dialog in multithread app?

[LaoWei]

How to show a modal dialog in multithread app? I want to show a modal dialog in multi thread application. But when I show the dialog as the fllowing, VC shows "Debug Assertion Failed" dialog. Anyone knows how to do it? Thanks very much. CAboutDlg dlg; dlg.DoModal(); The attachment is a demo. testmultithread.zip

[Robert Kuster]

Hi LaoWei. First, there is a little bug in your CreateMultiThread:

void CTestMultiThreadApp::CreateMultiThread()
{
DWORD tID;
g_nIndex**[1]** = 0;
::CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)ThreadProc, (LPVOID)&(g_nIndex**[0]), 0, &tID);
g_nIndex[1]** = 1;
::CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)ThreadProc, (LPVOID)&(g_nIndex**[1]**), 0, &tID);
}

Second, you use CreateThread in conjunction with MFC. This is dangerous. If your thread uses MFC support it should always be created via AfxBeginThread. Knowing this, you can write CreateMultiThread as follows:

void CTestMultiThreadApp::CreateMultiThread()
{
DWORD tID;
g_nIndex[0] = 0;
AfxBeginThread((AFX_THREADPROC)afxThreadProc,(LPVOID)&(g_nIndex[0]));

g\_nIndex\[1\] = 1;
**AfxBeginThread**((AFX\_THREADPROC)afxThreadProc,(LPVOID)&(g\_nIndex\[1\]));

}

Now your "Debug Assertion Failed" is gone bye bye... :) RK