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.

gcc    assumes preprocessed (.i) files are C and assumes C
       style linking.

g++    assumes preprocessed (.i) files are C++ and assumes
       C++ style linking.