请MFC高手进入，帮小弟解释下这写MFC代码，非常感谢。

Question

// MFC练习Dlg.cpp : implementation file
//

#include "stdafx.h"
#include "MFC练习.h"
#include "MFC练习Dlg.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

/////////////////////////////////////////////////////////////////////////////
// CMFCDlg dialog

CMFCDlg::CMFCDlg(CWnd* pParent /*=NULL*/)
: CDialog(CMFCDlg::IDD, pParent)
{
//{{AFX_DATA_INIT(CMFCDlg)
// NOTE: the ClassWizard will add member initialization here
//}}AFX_DATA_INIT
// Note that LoadIcon does not require a subsequent DestroyIcon in Win32
m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);
}

void CMFCDlg::DoDataExchange(CDataExchange* pDX)
{
CDialog::DoDataExchange(pDX);
//{{AFX_DATA_MAP(CMFCDlg)
// NOTE: the ClassWizard will add DDX and DDV calls here
//}}AFX_DATA_MAP
}

BEGIN_MESSAGE_MAP(CMFCDlg, CDialog)
//{{AFX_MSG_MAP(CMFCDlg)
ON_WM_PAINT()
ON_WM_QUERYDRAGICON()
//}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////

BOOL CMFCDlg::OnInitDialog()
{
CDialog::OnInitDialog();
this automatically
SetIcon(m_hIcon, TRUE);
SetIcon(m_hIcon, FALSE);

return TRUE;
to a control
}
the code below
document/view model,

void CMFCDlg::OnPaint()
{
if (IsIconic())
{
CPaintDC dc(this);
painting

SendMessage(WM_ICONERASEBKGND, (WPARAM) dc.GetSafeHdc(), 0);
int cxIcon = GetSystemMetrics(SM_CXICON);
int cyIcon = GetSystemMetrics(SM_CYICON);
CRect rect;
GetClientRect(&rect);
int x = (rect.Width() - cxIcon + 1) / 2;
int y = (rect.Height() - cyIcon + 1) / 2;
dc.DrawIcon(x, y, m_hIcon);
}
else
{
CDialog::OnPaint();
}
}
the user drags
HCURSOR CMFCDlg::OnQueryDragIcon()
{
return (HCURSOR) m_hIcon;
}

//////////////
刚学习MFC,帮小弟详细解释下上面的话,非常的感谢,非常的谢谢.—、—

Answer 1

该段代码中除了void CMFCDlg::OnPaint函数加了自己的处理之外，其他的都是MFC向导默认生成的，CMFCDlg::CMFCDlg(CWnd* pParent /*=NULL*/) 是构造函数；
void CMFCDlg::DoDataExchange(CDataExchange* pDX)是定义数据交换；
BEGIN_MESSAGE_MAP(CMFCDlg, CDialog) 定义消息映射；
BOOL CMFCDlg::OnInitDialog() 为对话框初始化函数；
void CMFCDlg::OnPaint() 窗口绘制函数；
程序在OnPaint函数中除了默认的窗口绘制之外，在窗口的右下角绘制了一个程序图标。