C / C++ / MFC

<br />
class CData<br />
{<br />
HWND m_hWnd;<br />
//Athor class members..<br />
}<br />

<br />
{<br />
//..<br />
//.. some of your code<br />
MyData.m_hWnd=(GetDlgItem(IDC_PROGRESS))->m_hWnd; //where IDC_PROGRESS <br />
<br />
is the ID of the progress bar..<br />
<br />
//now call AfxBeginThread<br />
AfxBeginThread(WorkerFn,&MyData, /*Ather args..*/);<br />
}<br />

<br />
UINT WorkerFn(LPVOID pData)<br />
{<br />
CData* data=(CData*)pData;<br />
CProgressCtrl* progBar=CWnd::FromHandle(data->m_hWnd);<br />
<br />
//Now use progBar as you wish!<br />
progBar->SetRange(0,100);<br />
//etc<br />
<br />
}<br />

<br />
::PostMessage(data->m_hWnd,WM_USER+1,0,0)<br />

Multithreaded apps are simplest if only the main thread deals with drawing the UI, as in your second solution. There is, however, no need to introduce a new message handler in your dialog. Just have the worker thread post a messages directly to the progress control:

Before starting the worker thread, save the window handle of the progress control in a variable that will be accessible to the worker thread (e.g. m_hProgressCtrl). Then in your worker thread code, post messages to update the progress control directly

<br />
::PostMessage (m_hProgressCtrl, PBM_SETRANGE, 0, MAKELPARAM (min, max));<br />
::PostMessage (m_hProgressCtrl, PBM_SETPOS, position, 0);<br />

Using ::PostMessage() (instead of the ::SendMessage() inside the CProgressBar member functions) means that the messages to update the progress controls will be queued for the main GUI thread.


Stephen C. Steel
Kerr Vayne Systems Ltd.