MFC中App,Doc,MainFrame,View各指针的互相获取

// App中获取其它三项指针
void CSDIApp::OnApp()
{
// App
// Doc
CDocument *pDoc = ((CFrameWndEx *)m_pMainWnd)->GetActiveDocument();//成员变量CFrameWndEx m_pMainWnd
// MainFrame
CFrameWndEx *pMain = (CFrameWndEx *)AfxGetMainWnd();
// View
CView *pView = ((CFrameWndEx *)m_pMainWnd)->GetActiveView();
}

// Doc中获取其它三项指针
CSDIDoc::CSDIDoc()//构造函数
{
// App
CWinAppEx *pApp = (CWinAppEx *)AfxGetApp();
// Doc
// MainFrame
// Doc的创建先于MainFrame
// View
// Doc的创建先于View
}
void CSDIDoc::OnDoc()
{
// App
// 同构造函数
// Doc
// MainFrame
CFrameWndEx *pMain = (CFrameWndEx *)AfxGetMainWnd();
// View
CView *pView= (CView *)pMain->GetActiveView();
POSITION pos = GetFirstViewPosition();
pView = GetNextView(pos);
}

// MainFrame中获取其它三项指针
CMainFrame::CMainFrame()//构造函数
{
theApp.m_nAppLook = theApp.GetInt(_T("ApplicationLook"), ID_VIEW_APPLOOK_VS_2005);
// App
CWinAppEx *pApp = (CWinAppEx *)AfxGetApp();
// Doc
// 构造函数里无法得到当前激活的Doc
// MainFrame
// View
// 构造函数里无法得到View指针，因为Main先于View创建。
}
void CMainFrame::OnMain()
{
// App
// 同构造函数
// Doc
CDocument *pDoc = (CDocument *)GetActiveDocument();
// MainFrame
// View
CView *pView = (CView *)GetActiveView();
}

// View中获取其它三项指针
CSDIView::CSDIView()//构造函数
{
// App
CWinAppEx *pApp = (CWinAppEx *)AfxGetApp();
// Doc
/* 无法在View的构造函数里得到Doc指针
GetDocument();实际上是返回m_pDocument
m_pDocument在OnCreate();里创建        */
//CDocument *pDoc = GetDocument();
// MainFrame
// 构造函数里无法得到MainFrame指针
// CFrameWndEx *pMain = (CFrameWndEx *)pApp->m_pMainWnd;
// View
}
void CSDIView::OnView()
{
// App
// 同构造函数
// Doc
CDocument *pDoc = GetDocument();
// MainFrame
CFrameWndEx *pMain = (CFrameWndEx *)AfxGetMainWnd();
// View
}

// Dlg中获取指针
CDlg::CDlg(CWnd* pParent /*=NULL*/)//构造函数
: CDialog(CDlg::IDD, pParent)
{
// App
CWinAppEx *pApp = (CWinAppEx *)AfxGetApp();
// Doc
CDocument *pDoc = ((CFrameWndEx *)AfxGetMainWnd())->GetActiveDocument();
// MainFrame
CFrameWndEx *pMain = (CFrameWndEx *)AfxGetMainWnd();
// View
CView *pView = ((CFrameWndEx *)AfxGetMainWnd())->GetActiveView();
}