MFC SetWindowPos question

Original Post

Apr 15, 2002 at 2:04 PM

everytime I try to use this function it crashes my program. I''m not sure if it only works for certain controls, but it doesn''t seem to work for any for me. first I a variable m_button that is a CButtton to a button control and then I use this code in OnSize(); m_button.SetWindowPos(NULL,0,0,cx/3,cy/3,NULL); the program always freezes on the line: ASSERT(::IsWindow(m_hwnd)) inside the SetWindowPos function, and the m_hwnd variable is always 0x000000 . any help would be greatly appreciated Dave

mikenitro

Apr 15, 2002 at 2:34 PM

Make sure that the window is actually realized (i.e., instantiated and rendered) before calling any window functions on it. In this case, the NULL window handle indicates that the window is not in existence yet, or that it is no longer in existence.

dalleboy

Apr 15, 2002 at 5:15 PM

I remember I had the same problem once, it was because OnSize was called before OnInitDialog, and thus no controls where created yet.

Try this:

void DaClass::OnSize(...)
{
if (::IsWindow(m_button.GetSafeHwnd()) != 0)
{
m_button.SetWindowPos(NULL,0,0,cx/3,cy/3,NULL);
}
}

// Dalle

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