C / C++ / MFC

// Defining a 'user defined' message for the call I wish to make
#define MYMESS_CALL_SOME_METHOD (WM_APP + 1)

struct ThreadParam
{
    HWND mDlg;    // Note: A handle.
};

UINT MyThreadProc( LPVOID pParam )
{
    ThreadParam* p = static_cast<ThreadParam*> (pParam);
    // Using message to call the method. Note: I could of course use the
    // WPARAM, LPARAM and returned value for something meaningful if I wished.
    ::SendMessage(p->mDlg, MYMESS_CALL_SOME_METHOD, 0, 0);
    delete p;
}

void CMyDialog::OnSomeButton()
{
     
    ThreadParam* param = new ThreadParam;
    param->mDlg = m_hWnd;  // A handle, not a dangerous 'this'
    AfxBeginThread(MyThreadProc, param);
    param = 0; // The other thread shall delete it    ...
}

//{{AFX_MSG(CMyDialog)
    ...
    afx_msg LRESULT OnCallSomeMethod(WPARAM, LPARAM);
    //}}AFX_MSG
    DECLARE_MESSAGE_MAP()

BEGIN_MESSAGE_MAP(CMyDialog, CDialog)
    //{{AFX_MSG_MAP(CMyDialog)
    ...
    ON_MESSAGE(MYMESS_CALL_SOME_METHOD, OnCallSomeMethod)
    //}}AFX_MSG_MAP
END_MESSAGE_MAP()

LRESULT CMyDialog::OnCallSomeMethod(WPARAM wp, LPARAM lp)
{
    callSomeMethod();
    return 0;
}

Michael Jansson wrote:

::SendMessage are thread safe!

Michael Jansson wrote:

SendMessage is thread-safe because can be called from multiple threads
without unwanted interaction between the threads

Michael Jansson wrote:

MFC is not thread safe.

glyfyx wrote:

Does anyone have an idea what's going on here?

<br />
void CMainFrame::GetListCtrl()<br />
{<br />
    CMyFormView *pView;<br />
<br />
    CListCtrl* pmyListCtrl = NULL;<br />
<br />
    if (pView)<br />
    {<br />
	   AfxMessageBox("view active");<br />
	  <br />
	   pmyListCtrl = pView->m_list_ctrl;<br />
<br />
	   int total = pmyListCtrl->GetItemCount();<br />
<br />
	   CString s;<br />
	   s.Format("total  = %i", total);<br />
	   AfxMessageBox(s);<br />
    }<br />
}<br />

CMyFormView *pView = NULL;

CListCtrl* pmyListCtrl = &pView->m_list_1098;

UINT ProcName(LPVOID param)
{
  {
     Do Something
  }
return 0;
}

AfxBeginThread( ProcName, param, priority );