class Base_Dlg : public ResizeDialog
...
class Child1_Dlg : public Base_Dlg
...
class Child2_Dlg : public Base_Dlg
...

BOOL OnInitSize()
{
	return FALSE;
}


BOOL OnRestoreSize(ODWP dwSizeInfo)
{
	void * p = (void*)dwSizeInfo;
	DLGSIZEINFO *pSz = (DLGSIZEINFO*)p;
	lstrcpyn(pSz->szDialogName, m_strDlgID, MAXLINE); // m_strDlgID is a string property I can change in derived classes
	
	...
	
	return TRUE;
}