Re: deriving helper class from CWnd

From:
=?Utf-8?B?amJyZWhlcg==?= <jbreher@discussions.microsoft.com>
Newsgroups:
microsoft.public.vc.mfc
Date:
Mon, 4 Feb 2008 11:34:01 -0800
Message-ID:
<691E163C-C61D-4987-AAC9-F128BA9E9FC0@microsoft.com>
"Scott McPhillips [MVP]" wrote:

Yes, it is necessary to call Create to give the CWnd an m_hWnd. If that is
not working then show your code. In fact, the help page for CWnd::Create
shows this example: Is your's this simple?

void CMyDlg::OnCreateStatic()
{
   CWnd* pWnd = new CWnd;
   pWnd->Create(_T("STATIC"), "Hi", WS_CHILD | WS_VISIBLE,
       CRect(0, 0, 20, 20), this, 1234);
}

Immediately after the Create call you should be able to add a SetTimer call.


Here is what I have tried:

BOOL CersatzbdsDlg::OnInitDialog()
{
    CDialog::OnInitDialog();

    // ...
    // TODO: Add extra initialization here
    MsgSendListInit();
    // trying to stop an assert failure on ASSERT(::IsWindow(m_hWnd) within
m_engine.SetTimer()
    m_engine.Create("BdsEngine", "engine", WS_CHILD, CRect(0, 0, 20, 20), this,
1234);
//...
}

The timer is later set from the UI CDialog by clicking a check control:

void CersatzbdsDlg::OnBnClickedCheckSendStatus()
{
    // TODO: Add your control notification handler code here
    UpdateData(TRUE);
    if(BST_CHECKED == m_ckSendStatusReq.GetCheck())
        m_engine.SendStatusStart();
    else m_engine.SendStatusStop();
}

and in the engine class:

void CBdsEngine::SendStatusStart()
{
    m_timerIdStatusRequest = SetTimer(4 /*TIMER_ID_STATUS_REQ*/, // timer ID
                                        m_StatusReqInterval, // Timeout
                                        0); // No callback
}

void CBdsEngine::SendStatusStop()
{
    KillTimer(m_timerIdStatusRequest);
}

void CBdsEngine::OnTimer(UINT_PTR nIDEvent)
{
    // See which timer event brought us here
    switch(nIDEvent)
    {
    case TIMER_ID_STATUS_REQ: //
-------------------------------------------------
        SendFdlStatusRequest();
        break;
    default:
        MessageBox("Unknown timer fired");
        break;
    }
}

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