timer and thread in mfc does not work.

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Hello, Good morning / afternoon / evening , Now i face a problem, i make a timer in my thread, it does not work at all..
but when i try to separate both of it.. it work normally,

here is the sample of my source code.

in .header

C++

static UINT MyThread(LPVOID pParam);
int a();
CWinThread* thread;
bool threadofmine;

in .cpp

C++

//this is the code i mean it does not work
void ____::OnClickedButton()
{
thread=AfxBeginThread(MyThread,this);
threadofmine=true;
}

UINT ____::MyThread(LPVOID pParam)
{
____* dialog;
dialog=(____*)pParam;
dialog->a();
return 0;
}

int  ____::a()
{
while(threadofmine)
{
SetTimer(1,1000,NULL);
group = 'a';
Sleep(100);
}
return 1;
}

void ____::OnTimer(UINT_PTR nIDEvent)
{
CDialogEx::OnTimer(nIDEvent);
switch(group)
{
case 'a':
{
timer+=1;
if(timer == 5)
{
MessageBox(NULL,NULL,NULL);
UpdateData(false);
}
break;
}

this is the code after i separate it,

C++

//for thread
void ___-:OnClickedButton()
{
thread=AfxBeginthread(MyThread,this);
threadofmine = true;
}

UINT ____::MyThread(LPVOID pParam)
{
____* dialog;
dialog=(____*)pParam;
dialog->a();
return 0;
}
 
int  ____::a()
{
while(threadofmine)
{
i+=1;
if(i==1)
{
MessageBox(L"1",NULL,NULL);
}
}return1;
}

this is for timer

C++

void ____::OnClickedButton()
{
SetTimer(1,1000,NULL);
group = 'a';
}

void ____::OnTimer(UINT_PTR nIDEvent)
{
CDialogEx::OnTimer(nIDEvent);
switch(group)
{
case 'a':
{
timer+=1;
if(timer == 5)
{
MessageBox(NULL,NULL,NULL);
UpdateData(false);
}
break;
}

please help me.. :"(

Posted 10-Oct-12 17:37pm

xnold

Updated 10-Oct-12 17:45pm

v3

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3 solutions

Solution 1

SetTimer should be called from the GUIThread[thread which created the window]. In the error case, MyThread() is calling SetTimer and it will not work.

You have to call it from

C++

void ____::OnClickedButton()

or
you should post a user message to GUIThread, and call SetTimer from the handler of user message.

Posted 10-Oct-12 17:54pm

Santhosh G_

Updated 10-Oct-12 18:05pm

v2

Comments

xnold 11-Oct-12 0:00am

thanks for the feedback.. :)
but the problem.. i have set multiple of timer in the case of 'group'
this is the example,

switch(group)
{
case 'a':
{
timer1+=1;
if(timer1==1)
{
KillTimer(1);
if(MessageBox(L"1",NULL,MB_OKCANCEL)==IDOK)
{
KillTimer(1);
SetTimer(2,1000,NULL);
timer='b';
}
UpdateData(false);
}
break;
}
case 'b':
{
timer2+=1;
if(timer2==1)
{
if(MessageBox(L"1",NULL,MB_OKCANCEL)==IDOK)
{
KillTimer(2);
// goto tryagain;
}
}
UpdateData(false);
}

xnold 11-Oct-12 0:00am

i try ur method... it worked on the 1st timer, but the other timer did not work..

xnold 11-Oct-12 0:03am

should i just change it to sleep in this kind of case??
but i worry bout the function of my code does not work due to it was in sleep mode

xnold 11-Oct-12 0:14am

how to post user message to the thread?? can u please gime a simple of sample code.. thanks :)

Solution 3

Just remember this as a rule: GUI updates should be made from the GUI thread. If you really want to learn how to send messages from a thread to the GUI, please check this article[^].

You will see that there are user messages sent from the thread, and there are handlers defined in the dialog like this:

C++

ON_MESSAGE(WM_MY_COPY_PROGRESS, &CImageCataloguerDlg::OnCopyProgress)

I think you should also create a synchronisation object (like a event) to allow stopping the thread if required.

I would also replaced the Sleep function with a WaitForSingleObject function to check is the synchronisation object signalled.

Posted 10-Oct-12 18:46pm

chaau

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Santhosh G_ · Accepted Answer · 2012-10-10T18:28:00

Solution 2

Message declaration.

C++

const int SET_TIMER_MESSAGE = WM_USER + 1 // User Mesasge

message handler modification.

// Add message handler in message map.
ON_MESSAGE( SET_TIMER_MESSAGE, OnMySetTimerMessage )

// Message handler implementation.

C++

void MyDlgClass::OnMySetTimerMessage( WPARAM dwWParam_i, LPARAM dwLParam_i)
{
    // Process GUI actions. like SetTimer, UpdateData etc..
}

// Non-GUI thread sending message to GUI thread for gui related operations.

C++

UINT MyThread()
{
// Non gui actions 

...

// Send message to GUI for GUI actions
ptrDlgHandle->PostMessage( SET_TIMER_MESSAGE, 0,0 );
}

Posted 10-Oct-12 18:28pm

Santhosh G_

Comments

xnold 11-Oct-12 0:31am

thx.. :)

xnold 18-Oct-12 1:22am

hai.. sorry for bothering you,, i would like to ask,,, ptrDlgHandle u declare it as ??

Santhosh G_ 18-Oct-12 2:43am

ptrDlgHandle is the handle to the window. It can be declared in global scope, and assign m_hWnd to it from OnInitDialog().
Or you can use findwindow to get the GUI from the thread.

xnold 18-Oct-12 20:41pm

ic.. thx for ur feedback.. :)