将窗格停靠到子框架

有时，应用程序必须具有不与主框架对接而是与子框架对接的窗格。通常它是 MDI 应用程序。在 MFC Feature Pack 中，这样的子帧是从 CMDIChildWndEx 类继承的，并且作为主框架（继承自 CMDIFrameWndEx）具有此类对接所需的所有代码。

但是儿童框架有一些技巧。这个例子展示了它们。

// Declare child frame
class CChildFrame : public CMDIChildWndEx
{
    DECLARE_DYNCREATE(CChildFrame)

protected:
    // declare our pane
    CDockablePane m_wndPane;

public:
    CChildFrame();

protected:
    virtual BOOL PreCreateWindow(CREATESTRUCT& cs);
    
    // CMDIChildWndEx class haven't serialization for state of the docking manager,
    // so we need to realize it manually.
    //
    // Docking state serialization methods:
    virtual void SaveBarState(LPCTSTR lpszProfileName) const;
    virtual void LoadBarState(LPCTSTR lpszProfileName);

protected:
    afx_msg int OnCreate(LPCREATESTRUCT lpCreateStruct);
    afx_msg void OnDestroy();

    DECLARE_MESSAGE_MAP()
};

// CChildFrame Implementation 

IMPLEMENT_DYNCREATE(CChildFrame, CMDIChildWndEx)

BEGIN_MESSAGE_MAP(CChildFrame, CMDIChildWndEx)
    ON_WM_CREATE()
    ON_WM_DESTROY()
END_MESSAGE_MAP()

CChildFrame::CChildFrame()
{
    // Trick#1: Add this line for enable floating toolbars
    m_bEnableFloatingBars = TRUE;
}

BOOL CChildFrame::PreCreateWindow(CREATESTRUCT& cs)
{
    if( !CMDIChildWndEx::PreCreateWindow(cs) )
        return FALSE;

    cs.style = WS_CHILD | WS_VISIBLE | WS_OVERLAPPED | WS_CAPTION | WS_SYSMENU
        | FWS_ADDTOTITLE | WS_THICKFRAME | WS_MINIMIZEBOX | WS_MAXIMIZEBOX | WS_MAXIMIZE;

    // Trick#2: Add this line for remove the ugly client edge of the child frame.
    cs.dwExStyle &= (~WS_EX_CLIENTEDGE);

    return TRUE;
}

void CChildFrame::SaveBarState(LPCTSTR lpszProfileName) const
{
    const_cast<CChildFrame*>(this)->GetDockingManager()->SaveState(lpszProfileName);

    // Trick#3: we need to call serialization method of CMFCToolBar panes that may be docked to the child frame.
    CObList list;
    const_cast<CChildFrame*>(this)->GetDockingManager()->GetPaneList(list, FALSE, NULL, FALSE);
    if (list.GetCount() > 0) {
        POSITION pos = list.GetTailPosition();
        while (pos != NULL) {
            CMFCToolBar* pToolBar = DYNAMIC_DOWNCAST(CMFCToolBar, list.GetPrev(pos));
            if (pToolBar != nullptr) {
                pToolBar->SaveState(lpszProfileName);
            }
        }
    }
}

void CChildFrame::LoadBarState(LPCTSTR lpszProfileName)
{
    // Trick#3: we need to call serialization method of CMFCToolBar panes that may be docked to the child frame.
    CObList list;
    GetDockingManager()->GetPaneList(list, FALSE, NULL, FALSE);
    if (list.GetCount() > 0) {
        POSITION pos = list.GetTailPosition();
        while (pos != NULL) {
            CMFCToolBar* pToolBar = DYNAMIC_DOWNCAST(CMFCToolBar, list.GetPrev(pos));
            if (pToolBar != nullptr) {
                pToolBar->LoadState(lpszProfileName);
            }
        }
    }

    GetDockingManager()->LoadState(lpszProfileName);
    GetDockingManager()->SetDockState();
    GetDockingManager()->ShowDelayShowMiniFrames(TRUE);

    // Trick#4: MFC BUGFIX: force assigning the child frame docking manager to all miniframes (for details look at http://stackoverflow.com/q/39253843/987850).
    for (POSITION pos = GetDockingManager()->GetMiniFrames().GetHeadPosition(); pos != NULL;)
    {
        CWnd* pWndNext = (CWnd*)GetDockingManager()->GetMiniFrames().GetNext(pos);
        if (pWndNext != nullptr && pWndNext->IsKindOf(RUNTIME_CLASS(CPaneFrameWnd))) {
            STATIC_DOWNCAST(CPaneFrameWnd, pWndNext)->SetDockingManager(GetDockingManager());
        }
    }
}

int CChildFrame::OnCreate(LPCREATESTRUCT lpCreateStruct)
{
    bool bRes = CMDIChildWndEx::OnCreate(lpCreateStruct) == 0;
    if (bRes)
    {
        // enable docking
        EnableDocking(CBRS_ALIGN_ANY);

        // enable Visual Studio 2005 style docking window behavior
        CDockingManager::SetDockingMode(DT_SMART);

        // Creating the pane.
        // ID_VIEW_PANE_ID - pane ID, must be declared in resource.h
        // CRect(0, 0, 100, 100) - default pane size in floating state (pane is not docked to any frame sides).
        // CBRS_LEFT - default side for pane docking.
        if (!m_wndPane.Create(_T("My Pane"), this, CRect(0, 0, 100, 100), TRUE, ID_VIEW_PANE_ID, WS_CHILD | WS_VISIBLE | WS_CLIPSIBLINGS | WS_CLIPCHILDREN | CBRS_LEFT | CBRS_FLOAT_MULTI)) {
            TRACE0("Failed to create Pane\n");
            return -1; // failed to create
        }
        // Enable docking and redocking pane to frame any sides (you can pass a combination of CBRS_ALIGN_ flags)
        m_wndPane.EnableDocking(CBRS_ALIGN_ANY);

        // Dock pane to the default (left) side of the frame.
        DockPane(&m_wndPane);
    }

    // Loading dock manager state
    if (bRes) {
       LoadBarState(theApp.GetRegSectionPath(_T("ChildFrame")));
    }

    return bRes ? 0 : 1;
}

void CChildFrame::OnDestroy()
{
    // Save dock manager state
    SaveBarState(theApp.GetRegSectionPath(_T("ChildFrame")));

    CMDIChildWndEx::OnDestroy();
}