2009. 1. 16. 16:19

CWnd::GetCurrentMessage : 현재 메시지 핸들러가 처리하고 있는 MSG 정보 가져오기

2009. 1. 16. 16:19 in 3. Implementation/MFC

CWnd::GetCurrentMessage

This method obtains a pointer to the MSG structure that contains the message the window is currently processing.

static const MSG* PASCAL GetCurrentMessage( );

Return Value

Returns a pointer to the MSG structure that contains the message the window is currently processing. Should only be called when in an OnMessage handler.

Remarks

This method returns a pointer to a MSG structure. In Windows CE, the time member of this structure contains the system time at which CWnd::GetCurrentMessage is called, rather than the time at which the message was posted.

// The following example toggles two views in a single document
// interface (SDI) frame window. A design decision must be made about
// whether to leave the inactive view connected to the document,
// allowing the inactive view to continue receiveing OnUpdate
// notifications from the document. It is often desirable to
// keep the inactive view continuously in synchronization with the
// document, even though it is inactive. However, doing so incurs a
// performance cost,as well as the programming cost of implementing
// OnUpdate hints. It may be less expensive, in terms of performance and
// programming,to re-sync the inactive view with the document only when it
// is reactivated. The following example illustrates the latter approach, // by reconnecting the newly active view and disconnecting the newly
// inactive view, through calls to CDocument::AddView and RemoveView.

BOOL CMainFrame::OnViewChange(UINT nCmdID)
{
 CView* pViewAdd;
 CView* pViewRemove;
 CDocument* pDoc = GetActiveDocument();
 UINT nCmdID;
   
 nCmdID = LOWORD(GetCurrentMessage()->wParam);

 if((nCmdID == ID_VIEW_VIEW1) && (m_currentView == 1))
   return;
 if((nCmdID == ID_VIEW_VIEW2) && (m_currentView == 2))
  return;

 if (nCmdID == ID_VIEW_VIEW2)
 {
  if (m_pView2 == NULL)
  {
   m_pView1 = GetActiveView();
   m_pView2 = new CMyView2;

// If OnSize has been overridden in CMyView2
// and GetDocument() is used in this override it can
// cause assertions and, if the assertions are ignored,
// cause access violations.

   m_pView2->Create(NULL, NULL, AFX_WS_DEFAULT_VIEW,
     rectDefault, this, AFX_IDW_PANE_FIRST + 1, NULL);
  }
   pViewAdd = m_pView2;
   pViewRemove = m_pView1;
   m_currentView= 2;
 }
 else
 {
  pViewAdd = m_pView1;
  pViewRemove = m_pView2;
  m_currentView= 1;
 }
    
// Set the child identifier of the active view to AFX_IDW_PANE_FIRST,
// so that CFrameWnd::RecalcLayout will allocate to this
// first pane, that portion in a client area of the frame window that is
// not allocated to control bars. Set the child identifier of the
// other view to anything besides AFX_IDW_PANE_FIRST; this
// example switches the child identifiers of the two views.

 int nSwitchChildID = pViewAdd->GetDlgCtrlID();
 pViewAdd->SetDlgCtrlID(AFX_IDW_PANE_FIRST);
 pViewRemove->SetDlgCtrlID(nSwitchChildID);

 // Show the newly active view and hide the inactive view.

 pViewAdd->ShowWindow(SW_SHOW);
 pViewRemove->ShowWindow(SW_HIDE);

 // Connect the newly active view to the document and
 // disconnect the inactive view.
 pDoc->AddView(pViewAdd);
 pDoc->RemoveView(pViewRemove);

 SetActiveView(pViewAdd);
 RecalcLayout();
}

출처 : MSDN