C / C++ / MFC

//Define thread message.
#define WM_THREAD_WORKING  (WM_USER + 1)
 
//Define a structure.
typedef struct _thread_info_tag
{
  HWND pNotifyWnd;
  long lValue1;
  int nValue2;
  char szValue3[80];
} _thread_info;
 
class CMyDialog : public CDialog
{
  .
  .
  //Thread function.
  static UINT ThreadFunc(LPVOID lpParam);
  .
  .
  // Generated message map functions
  //{{AFX_MSG(CProdDataWestDlg)
  .
  .
  //}}AFX_MSG
  //Add message handler.
  afx_msg LRESULT OnThreadMessge(WPARAM wParam, LPARAM lParam);
  DECLARE_MESSAGE_MAP()
};

//Add handler to message map.
BEGIN_MESSAGE_MAP(CMyDialog, CDialog)
  //{{AFX_MSG_MAP(CMyDialog)
  .
  .
  //}}AFX_MSG_MAP
  ON_MESSAGE(WM_THREAD_WORKING, OnThreadMessge)
END_MESSAGE_MAP()
 
//Somewhere start the thread.
CMyDialog::OnStartThread()
{
  _thread_info *pInfo = new _thread_info; //Thread must delete this!
  pInfo->pNotifyWnd = this->GetSafeHwnd();
  pInfo->lValue1 = 12345;
  pInfo->nValue2 = -321;
  strcpy(pInfo->szValue3, "String for thread.");
 
  //Now start the thread.
  AfxBeginThread(ThreadFunc, (LPVOID)pInfo);
  .
  .
}
 
UINT CMyDialog::ThreadFunc(LPVOID lpParam)
{
  //Get thread data
  ASSERT(lpParam);
  _thread_info *pInfo = (_thread_info *)lpParam;
 
  HWND pNotifyWnd = pInfo->pNotifyWnd;
  long lValue1 = pInfo->lValue1;
  int nValue2 = pInfo->nValue2;
  char szValue3[80];
  strcpy(szValue3, pInfo->szValue3);
 
  //Delete pInfo.
  delete pInfo;
 
  .
  .
  //Post message to window.
  ::PostMessage(pNotifyWnd, WM_THREAD_WORKING, 0, 0);
  .
  .
}
 
LRESULT CMyDialog::OnThreadMessge(WPARAM wParam, LPARAM lParam)
{
  //Handle message.
  .
  .
  return 0;
}

if(Nish)
  AfxMessageBox("Whats up?");
else
  AfxMessageBox("Are you there..?");