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Hello Everyone,

I am working on an application in which there is a dialog box. On one side of a dialog box there is a custom and on other side there is Tab Control. Am using the custom control for displaying a Bar graph which is updating continuously depending on the values am receiving via USB port. On one of the tabs(child dialog) of Tab control I have placed a slider control.

I have written the thread for Bar control in OnInitDialog() function of the main dialog box. As soon as I move the slider control on child window, the bar control stops updating. What should I do to start that thread again after I release the slider control?

I can't make any changes in the GUI now. How can I call the thread again from the child window?

Here is the code where am creating the thread and the thread function.

BOOL CMonitorMediaSensor::OnInitDialog()

        SetBackgroundColor (g_DlgColor);

	// TODO:  Add extra initialization here

	m_chart.SubclassDlgItem(IDC_CUSTOMSENSORBAR, this);
	m_chart.AddValue(m_nSensorValue,"Sensor Value");
	m_chart.m_nMode = 0;

	// Create Tab: Used to display calibration Bar
	m_SnapDlg = new CMediaSensorSnapDlg;
	m_SnapDlg->Create(CMediaSensorSnapDlg::IDD, &m_SnapTabCtrl);
	m_SnapTabCtrl.AddTab(m_SnapDlg, "Calibrate", 0);
	m_SnapDlg->m_pSnapTabCtrl = &m_SnapTabCtrl;
	m_SnapDlg->m_chart.m_nMode = 1;

	// Create Tab: Used for Media Profiling.
	m_SnapDlgMonitor  = new CMediaSensorSnapDlg;
	m_SnapDlgMonitor->Create(CMediaSensorSnapDlg::IDD, &m_SnapTabCtrl);
	m_SnapTabCtrl.AddTab(m_SnapDlgMonitor, "Profiling", 1);
	m_SnapDlgMonitor->m_pSnapTabCtrl = &m_SnapTabCtrl;
	m_SnapDlgMonitor->m_chart.m_nMode = 0;

	  // Create tab: Used for Sensor Gain Adjustment
	m_SensorGainDlg  = new CSensorGain;
	m_SensorGainDlg->Create(CSensorGain::IDD, &m_SnapTabCtrl);
	m_SnapTabCtrl.AddTab(m_SensorGainDlg, "Sensor Gain", 2);
	m_SnapDlgMonitor->m_pSnapTabCtrl = &m_SnapTabCtrl;
	//m_SnapDlgMonitor->m_chart.m_nMode = 0;
	m_SnapTabCtrl.SetCurFocus (1);

		Start Media sensor thread. Thread sends commands to USB Port to get 
                current media sensor values. 
	g_portio->m_bCloseMediaSensorThread = FALSE;
	m_bCloseSensorMonitorThread = FALSE;
	m_MediaSensorData = new MEDIASENSORDATA;

	m_MediaSensorData->pbCloseThread	= &m_bCloseSensorMonitorThread;
	m_MediaSensorData->pCS				= &g_portio->m_CS;

	/* Create thread. */
	m_hMediaSensor = AfxBeginThread (MonitorMediaSensorProc,

	return TRUE;  // return TRUE unless you set the focus to a control
	// EXCEPTION: OCX Property Pages should return FALSE

UINT MonitorMediaSensorProc (LPVOID	pParam)
	BOOL*			pbCloseThread	= monData->pbCloseThread;
	CCriticalSection*	pcs		= monData->pCS;

	CSingleLock		lock(pcs);
	char	                szQueryCommand[6];

	szQueryCommand[0] = g_cSTX;
	szQueryCommand[1] = 'K';
	szQueryCommand[2] = 'L';
	szQueryCommand[3] = g_cCR;
	szQueryCommand[4] = 0x0A;
	szQueryCommand[5] = '\0';

	while (1)
		if(lock.Lock ())
			if(g_portio->m_bCloseMediaSensorThread || *pbCloseThread)
				lock.Unlock ();

				monData = NULL;
				return 0;
			/* Send query command to USB Port. */
			g_portio->SendData (szQueryCommand, 6);
			lock.Unlock ();

		Sleep (100);

	return 0;
Updated 26-May-13 22:55pm
Richard MacCutchan 27-May-13 4:31am
You need to show some of your code and explain how the thread is getting terminated; it's impossible to guess what your program is doing.
Fresher16 27-May-13 4:55am
I have updated my question... Please have a look.
Santhosh G_ 27-May-13 11:46am
MonitorMediaSensorProc will remain until the following condition satisfies.
if(g_portio->m_bCloseMediaSensorThread || *pbCloseThread)
In my suggestion MonitorMediaSensorProc should not return until the all SendData() operation completed. Restarting the thread to send each command is not a good design.

1 solution

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Solution 1

Its working properly now.
I was doing something wrong on the child window.

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