构建一个动态的用户界面，使用一个CWnd空闲池

// CWndContainer manages a collection of CWndControl instances and

// is designed for attachment to a CDialog such as CControlDlg.

// When a control is added to the container, the free pool is used

// to acquire an appropriate CWnd for attachment to the control.<

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// If none is available, the container will create a new CWnd for



// it by using the factory class. When a control is removed from<

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// the container, its CWnd is detached and added to the free pool



// for later reuse.

class CWndContainer

{

public:

    CWndContainer();

     CWndContainer();

    

    // Attach to CDialog.

    void AttachWnd(CWnd* pWnd);

    void DetachWnd();

    

    // Set resource ID range for control CWnds.

    void SetResourceIdRange(UINT minResourceId, UINT maxResourceId);

    

    // Control management.

    void AddControl(CWndControl* pControl);

    void AddControls(const std::list<CWndControl*>& controlList);

    void RemoveControl(CWndControl* pControl);

    void RemoveAllControls();

    

    // Find controls.

    CWndControl* GetControl(const CString& controlName);

    CWndControl* GetControl(UINT resourceId);

    void         GetControls(std::list<CWndControl*>& controlList) const;



    // Message handling.

    BOOL OnCmdMsg(UINT nID, int nCode, void* pExtra, 

                  AFX_CMDHANDLERINFO* pHandlerInfo);

};

// IWndEventHandler interface.

class IWndEventHandler

{

public:

    virtual void HandleWndEvent(const CWndEvent& ev) = 0;

};

// CWndEvent class.

class CWndEvent

{

public:

    // Constructor / destructor.

    CWndEvent(CWndControl* sender, const CString& text);

     CWndEvent();

    

    // Public methods.

    CWndControl* GetSender() const;

    CString      GetText() const;

    void         AddProperty(const CString& name, const CString& value);

    bool         GetProperty(const CString& name, CString& value) const;

};

// Filename: MyDlg.h



...



#include "WndEvent.h"



// Forward declarations.

class CWndContainer;

class CWndButton;



// CMyDlg class.

class CMyDlg : public CDialog, public IWndEventHandler

{

    DECLARE_DYNAMIC(CMyDlg)



public:

    CMyDlg(CWnd* pParent = NULL);

    virtual  CMyDlg();



    // IWndEventHandler overrides.

    virtual void HandleWndEvent(const CWndEvent& ev);



    ...



protected:

    virtual BOOL OnInitDialog();    

    virtual BOOL OnCmdMsg(UINT nID, int nCode, void* pExtra,

                          AFX_CMDHANDLERINFO* pHandlerInfo);

    ...

        

private:

    CWndContainer* m_container;

    CWndButton*    m_button;

    

    ...

};



...

// Filename: MyDlg.cpp



#include "stdafx.h"

#include "MyDlg.h"

#include "WndContainer.h"

#include "WndControl.h"



...



CMyDlg::CMyDlg(CWnd* pParent /*=NULL*/)

    : CDialog(CMyDlg::IDD, pParent)

{

    m_button = NULL;



    // Create an instance of the container

    // and attach it to the dialog.

    m_container = new CWndContainer;

    m_container->AttachWnd(this);    

}



CMyDlg:: CMyDlg()

{

    // Detach the container from the dialog

    // and then delete it.

    m_container->DetachWnd();

    delete m_container;



    // Delete the button.

    delete m_button;

}



BOOL CMyDlg::OnInitDialog()

{

    CDialog::OnInitDialog();

    

    // Create a CWndButton and set its properties.

    m_button = new CWndButton;

    m_button->SetName(_T("Button1"));

    m_button->SetText(_T("Hello World!"));

    m_button->SetLocation(CPoint(10,10));

    m_button->SetSize(CSize(100,24));



    // Attach an event handler to the button.

    m_button->AddEventHandler(this);



    // Add the button to the container.

    m_container->AddControl(m_button);



    return TRUE;  // return TRUE unless you set the focus to a control

                  // EXCEPTION: OCX Property Pages should return FALSE

}



BOOL CMyDlg::OnCmdMsg(UINT nID, int nCode, void* pExtra, AFX_CMDHANDLERINFO* pHandlerInfo)

{

    // Let the container handle the message.

    if ( m_container != NULL )

    {

        BOOL isHandled = m_container->OnCmdMsg(nID, nCode, pExtra, pHandlerInfo);

        if ( isHandled )

            return TRUE;

    }

    

    return CDialog::OnCmdMsg(nID, nCode, pExtra, pHandlerInfo);    

}



void CMyDlg::HandleWndEvent(const CWndEvent& ev)

{

    if ( ev.GetSender()->GetName() == _T("Button1") )

    {

        MessageBox(ev.GetText(), _T("CMyDlg"));

    }

}



...