About Delete Modless Dialog

//MainWindow.h
CMyDialog m_Dlg;

//MainWindow.cpp
m_Dlg.Create();
m_Dlg.ShowWindow();

// SomeWhere1:
m_Dlg.DestroyWindow();
//Here,I Wanto To Whether Controls Resource On m_Dlg Is Deleted SuccessFully 

// SomeWhere2:
if(m_Dlg.GetSafeHwnd() == NULL){
   m_Dlg..Create();
   m_Dlg.ShowWindow();
}