Dialog based application and generated OnPaint for the dialog class

From:
Eric Lilja <mindcoolerremoveme@gmail.com>
Newsgroups:
microsoft.public.vc.mfc
Date:
Mon, 06 Aug 2007 17:10:39 +0200
Message-ID:
<eLAA1vD2HHA.3760@TK2MSFTNGP03.phx.gbl>
Hello, I'm using MSVC++ 8.0 SP1 and I created a dialog based MFC
application using the application wizard. In my CDialog-derived class,
MyDialog, the appwizard generated the following OnPaint() for me:

// If you add a minimize button to your dialog, you will need the code below
// to draw the icon. For MFC applications using the document/view model,
// this is automatically done for you by the framework.
void
MyDialog::OnPaint()
{
    if (IsIconic())
    {
       CPaintDC dc(this); // device context for painting

       SendMessage(WM_ICONERASEBKGND,
reinterpret_cast<WPARAM>(dc.GetSafeHdc()), 0);

       // Center icon in client rectangle
       int cxIcon = GetSystemMetrics(SM_CXICON);
       int cyIcon = GetSystemMetrics(SM_CYICON);
       CRect rect;
       GetClientRect(&rect);
       int x = (rect.Width() - cxIcon + 1) / 2;
       int y = (rect.Height() - cyIcon + 1) / 2;

       // Draw the icon
       dc.DrawIcon(x, y, m_hIcon);
    }
    else
    {
       CDialog::OnPaint();
    }
}

The comment says that I need this to display an icon if I decide to add
a minimize button to my dialog if I'm not using docview. Well, I added a
minimize button and commented everything up to and including the
else-statement out, and it displays the icon just fine. But I don't have
a document or a view class and I don't recall making any particular
choices about that when I went through the appwizard.

So it seems I have a framework support application even though I have no
view or document class and that means I don't have to redefine OnPaint()
as far as displaying an icon for a dialog with a minimize box is
concerned, is that right? I'd like to remove this OnPaint() if I don't
need it. No use doing something that the framework is already taking
care of.

- Eric

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