Re: Non-modal dialog pParent initialization (and warning C4355)

"Doug Harrison [MVP]" <>
Wed, 21 Mar 2007 13:53:38 -0500
On 10 Mar 2007 19:23:22 -0800, "Harvey" <> wrote:

I have read several posts about "warning C4355: 'this' : used in base
member initializer list", and I understand about the object of 'this'
not being fully initialized, but that it is common 'safe' practice to
use this method to only save a pointer for future use..
OK, my question is;
What is the proper or best way to initialize a non-modal dialog?

I have used two methods:


CFooDlg::CFooDlg(CWnd* pParent /*=NULL*/)
  : CDialog(IDD, pParent)
  // pParent is not set here, See Create

BOOL CFooDlg::Create(CWnd * pParent)
  pCV=(CMyBar *) pParent;


CMyBar::CMyBar(CWnd* pParent /*=NULL*/)
  : CDialog(CMyBar::IDD, pParent),
  CFooDlg( this ) // <---- Warning C4355

CFooDlg::CFooDlg(CWnd* pParent /*=NULL*/)
  : CDialog(IDD, pParent)
  pCV=(CMyBar *) pParent;

But method (2) seems more natural but it gives me warning C4355.
Is there a simpler cleaner way?

You can ignore C4355. Myself, I routinely disable it. The only way you can
get into trouble by simply storing a pointer is if it must be converted to
a base class whose construction hasn't begun in a multiple inheritance
setting; this is undefined, IIRC, but it shouldn't be an issue for MFC
window classes since they don't normally use MI anyway, and if they do, the
CWnd part is the left-most base.

BTW, unless CFooDlg is a private nested class of CMyBar or access to it is
otherwise restricted, casting to CMyBar as above is suspect and should be
replaced with a dynamic_cast or verified with MFC-style RTTI. Better still,
you can make CFooDlg's ctor take a CMyBar* instead of CWnd*. I would not do
this for Create or recommend writing Create as you have above.
CDialog::Create is a virtual function, but you are not overriding it in
CFooDlg, because you've changed its signature. This is bad because anyone
can call one of the CDialog::Create overloads through a pointer or
reference to the CDialog part of your CFooDlg object, bypassing what you do
in your Create.

Doug Harrison
Visual C++ MVP

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