#ifndef MY_APP_H_

#define MY_APP_H_

#include <afxwin.h>

class CMyApp:public CWinApp

{

public:

    virtual BOOL InitInstance();

};

#endif

=====================================

#include "stdafx.h"

#include "MyApp.h"

#include "resource.h"

#include "MyCustomCDialog.h"

BOOL CMyApp::InitInstance()

{

    /*

    CDialog dialog;

    dialog.Create(IDD_DIALOG_FIRST,NULL);

    dialog.ShowWindow(m_nCmdShow);

    */

    CMyCustomCDialog myDialog;

    myDialog.DoModal();

    //myDialog.ShowWindow(m_nCmdShow);

    /*myDialog.UpdateData(true);

    std::string result(myDialog.m_cstrEditFirst.GetBuffer());

    myDialog.m_cstrEditFirst.ReleaseBuffer();

    */

    ::MessageBox(NULL,"Message","Title",MB_OK);

    myDialog.DestroyWindow();

    return true;

}

CMyApp myApp;

#ifndef MY_CUSTOM_CDIALOG_H_

#define MY_CUSTOM_CDIALOG_H_

#include <afxwin.h>

#include "resource.h"

#include <string>

class CMyCustomCDialog:public CDialog

{

public:

    CMyCustomCDialog(CWnd* pParent=NULL);

    enum{ IDD=IDD_DIALOG_FIRST };

    //Overrides

protected:

    virtual void DoDataExchange(CDataExchange* pDX);

    //Implement

protected:

    afx_msg void OnDoAction();

    DECLARE_MESSAGE_MAP()

public:

    CString m_cstrEditFirst;

};

#endif

======================================

#include "stdafx.h"

#include "MyCustomCDialog.h"

CMyCustomCDialog::CMyCustomCDialog(CWnd* pParent)

    :CDialog(CMyCustomCDialog::IDD,pParent)

{

}

void CMyCustomCDialog::DoDataExchange(CDataExchange* pDX)

{

    CDialog::DoDataExchange(pDX);

    ::MessageBox(NULL,"Message_DoDataExchange","Title",MB_OK);

    DDX_Text(pDX,IDC_EDIT_FIRST,m_cstrEditFirst);

}

BEGIN_MESSAGE_MAP(CMyCustomCDialog,CDialog)

    ON_BN_CLICKED(IDC_BUTTON_ACTION,OnDoAction)

END_MESSAGE_MAP()

void CMyCustomCDialog::OnDoAction()

{

    HWND hWnd=::GetDlgItem(this->m_hWnd,IDC_EDIT_FIRST);

    char* pChar=new char[];

    memset(pChar,'\0',);

    ::GetWindowText(hWnd,pChar,);

    m_cstrEditFirst.Format("%s",pChar);

}