帮我写一个MFC网络编程的程序

好的，这里提供一个简单的MFC网络编程的程序，实现了客户端和服务器端的通信。

客户端代码：

#include "stdafx.h"
#include "Client.h"
#include "ClientDlg.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#endif

CWinApp theApp;

using namespace std;

int main(int argc, TCHAR* argv[], TCHAR* envp[])
{
    int nRetCode = 0;

    HMODULE hModule = ::GetModuleHandle(nullptr);

    if (hModule != nullptr)
    {
        // 初始化 MFC 并在失败时显示错误
        if (!AfxWinInit(hModule, nullptr, ::GetCommandLine(), 0))
        {
            // TODO: 请更改错误代码以符合您的需要
            wprintf(L"严重错误: MFC 初始化失败\n");
            nRetCode = 1;
        }
        else
        {
            // 创建对话框并运行
            CClientDlg dlg;
            theApp.m_pMainWnd = &dlg;
            nRetCode = dlg.DoModal();
        }
    }
    else
    {
        // TODO: 请更改错误代码以符合您的需要
        wprintf(L"严重错误: GetModuleHandle 失败\n");
        nRetCode = 1;
    }

    return nRetCode;
}

服务器端代码：

#include "stdafx.h"
#include "Server.h"
#include "ServerDlg.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#endif

CWinApp theApp;

using namespace std;

int main(int argc, TCHAR* argv[], TCHAR* envp[])
{
    int nRetCode = 0;

    HMODULE hModule = ::GetModuleHandle(nullptr);

    if (hModule != nullptr)
    {
        // 初始化 MFC 并在失败时显示错误
        if (!AfxWinInit(hModule, nullptr, ::GetCommandLine(), 0))
        {
            // TODO: 请更改错误代码以符合您的需要
            wprintf(L"严重错误: MFC 初始化失败\n");
            nRetCode = 1;
        }
        else
        {
            // 创建对话框并运行
            CServerDlg dlg;
            theApp.m_pMainWnd = &dlg;
            nRetCode = dlg.DoModal();
        }
    }
    else
    {
        // TODO: 请更改错误代码以符合您的需要
        wprintf(L"严重错误: GetModuleHandle 失败\n");
        nRetCode = 1;
    }

    return nRetCode;
}

客户端对话框代码：

#include "stdafx.h"
#include "Client.h"
#include "ClientDlg.h"
#include <winsock2.h>
#include <iostream>
#include <string>

#pragma comment(lib,"ws2_32.lib")

using namespace std;

#ifdef _DEBUG
#define new DEBUG_NEW
#endif

#define BUFFER_SIZE 1024

CClientDlg::CClientDlg(CWnd* pParent /*=nullptr*/)
    : CDialogEx(IDD_CLIENT_DIALOG, pParent)
{
    m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);
}

void CClientDlg::DoDataExchange(CDataExchange* pDX)
{
    CDialogEx::DoDataExchange(pDX);
    DDX_Control(pDX, IDC_EDIT1, m_EditBox);
    DDX_Control(pDX, IDC_SEND, m_SendButton);
    DDX_Control(pDX, IDC_IPADDRESS1, m_ServerIP);
    DDX_Control(pDX, IDC_PORT, m_Port);
}

BEGIN_MESSAGE_MAP(CClientDlg, CDialogEx)
    ON_WM_PAINT()
    ON_WM_QUERYDRAGICON()
    ON_BN_CLICKED(IDC_SEND, &CClientDlg::OnBnClickedSend)
    ON_WM_CLOSE()
END_MESSAGE_MAP()

BOOL CClientDlg::OnInitDialog()
{
    CDialogEx::OnInitDialog();

    // 将“关于...”菜单项添加到系统菜单中。

    // IDM_ABOUTBOX 必须在系统命令范围内。
    ASSERT((IDM_ABOUTBOX & 0xFFF0) == IDM_ABOUTBOX);
    ASSERT(IDM_ABOUTBOX < 0xF000);

    CMenu* pSysMenu = GetSystemMenu(FALSE);
    if (pSysMenu != nullptr)
    {
        CString strAboutMenu;
        strAboutMenu.LoadString(IDS_ABOUTBOX);
        if (!strAboutMenu.IsEmpty())
        {
            pSysMenu->AppendMenu(MF_SEPARATOR);
            pSysMenu->AppendMenu(MF_STRING, IDM_ABOUTBOX, strAboutMenu);
        }
    }

    // 设置此对话框的图标。当应用程序主窗口不是对话框时，框架将自动
    //  执行此操作
    SetIcon(m_hIcon, TRUE);         // 设置大图标
    SetIcon(m_hIcon, FALSE);        // 设置小图标

    // TODO: 在此添加额外的初始化代码
    WSADATA wsaData;
    if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0) {
        MessageBox(_T("Failed to load Winsock library!"), _T("Error"), MB_ICONERROR | MB_OK);
        return FALSE;
    }

    return TRUE;  // 除非将焦点设置到控件，否则返回 TRUE
}

void CClientDlg::OnPaint()
{
    if (IsIconic())
    {
        CPaintDC dc(this); // 用于绘制的设备上下文

        SendMessage(WM_ICONERASEBKGND, reinterpret_cast<WPARAM>(dc.GetSafeHdc()), 0);

        // 将图标居中绘制
        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;

        // 绘制图标
        dc.DrawIcon(x, y, m_hIcon);
    }
    else
    {
        CDialogEx::OnPaint();
    }
}

HCURSOR CClientDlg::OnQueryDragIcon()
{
    return static_cast<HCURSOR>(m_hIcon);
}

void CClientDlg::OnClose()
{
    WSACleanup();
    CDialogEx::OnClose();
}

void CClientDlg::OnBnClickedSend()
{
    // 获取服务器IP和端口号
    CString serverIPStr;
    m_ServerIP.GetWindowText(serverIPStr);
    char* serverIP = CStringA(serverIPStr).GetBuffer();
    CString portStr;
    m_Port.GetWindowText(portStr);
    int port = _ttoi(portStr);

    // 创建socket
    SOCKET sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (sock == INVALID_SOCKET) {
        MessageBox(_T("Failed to create socket!"), _T("Error"), MB_ICONERROR | MB_OK);
        return;
    }

    // 设置服务器地址
    SOCKADDR_IN serverAddr;
    serverAddr.sin_family = AF_INET;
    serverAddr.sin_port = htons(port);
    serverAddr.sin_addr.s_addr = inet_addr(serverIP);

    // 连接服务器
    if (connect(sock, (SOCKADDR*)&serverAddr, sizeof(serverAddr)) == SOCKET_ERROR) {
        MessageBox(_T("Failed to connect to server!"), _T("Error"), MB_ICONERROR | MB_OK);
        closesocket(sock);
        return;
    }

    // 发送数据
    CString msg;
    m_EditBox.GetWindowText(msg);
    char* buffer = CStringA(msg).GetBuffer();
    int len = strlen(buffer);
    send(sock, buffer, len, 0);

    // 接收数据
    char recvBuffer[BUFFER_SIZE] = {};
    int recvLen = recv(sock, recvBuffer, BUFFER_SIZE, 0);
    CString recvMsg = CString(recvBuffer, recvLen);
    MessageBox(recvMsg, _T("Message Received"), MB_ICONINFORMATION | MB_OK);

    // 关闭socket
    closesocket(sock);
}

服务器端对话框代码：

#include "stdafx.h"
#include "Server.h"
#include "ServerDlg.h"
#include <winsock2.h>
#include <iostream>
#include <string>

#pragma comment(lib,"ws2_32.lib")

using namespace std;

#ifdef _DEBUG
#define new DEBUG_NEW
#endif

#define BUFFER_SIZE 1024

CServerDlg::CServerDlg(CWnd* pParent /*=nullptr*/)
    : CDialogEx(IDD_SERVER_DIALOG, pParent)
{
    m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);
}

void CServerDlg::DoDataExchange(CDataExchange* pDX)
{
    CDialogEx::DoDataExchange(pDX);
    DDX_Control(pDX, IDC_EDIT1, m_EditBox);
    DDX_Control(pDX, IDC_LISTEN, m_ListenButton);
    DDX_Control(pDX, IDC_PORT, m_Port);
}

BEGIN_MESSAGE_MAP(CServerDlg, CDialogEx)
    ON_WM_PAINT()
    ON_WM_QUERYDRAGICON()
    ON_BN_CLICKED(IDC_LISTEN, &CServerDlg::OnBnClickedListen)
    ON_WM_CLOSE()
END_MESSAGE_MAP()

BOOL CServerDlg::OnInitDialog()
{
    CDialogEx::OnInitDialog();

    // 将“关于...”菜单项添加到系统菜单中。

    // IDM_ABOUTBOX 必须在系统命令范围内。
    ASSERT((IDM_ABOUTBOX & 0xFFF0) == IDM_ABOUTBOX);
    ASSERT(IDM_ABOUTBOX < 0xF000);

    CMenu* pSysMenu = GetSystemMenu(FALSE);
    if (pSysMenu != nullptr)
    {
        CString strAboutMenu;
        strAboutMenu.LoadString(IDS_ABOUTBOX);
        if (!strAboutMenu.IsEmpty())
        {
            pSysMenu->AppendMenu(MF_SEPARATOR);
            pSysMenu->AppendMenu(MF_STRING, IDM_ABOUTBOX, strAboutMenu);
        }
    }

    // 设置此对话框的图标。当应用程序主窗口不是对话框时，框架将自动
    //  执行此操作
    SetIcon(m_hIcon, TRUE);         // 设置大图标
    SetIcon(m_hIcon, FALSE);        // 设置小图标

    // TODO: 在此添加额外的初始化代码
    WSADATA wsaData;
    if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0) {
        MessageBox(_T("Failed to load Winsock library!"), _T("Error"), MB_ICONERROR | MB_OK);
        return FALSE;
    }

    return TRUE;  // 除非将焦点设置到控件，否则返回 TRUE
}

void CServerDlg::OnPaint()
{
    if (IsIconic())
    {
        CPaintDC dc(this); // 用于绘制的设备上下文

        SendMessage(WM_ICONERASEBKGND, reinterpret_cast<WPARAM>(dc.GetSafeHdc()), 0);

        // 将图标居中绘制
        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;

        // 绘制图标
        dc.DrawIcon(x, y, m_hIcon);
    }
    else
    {
        CDialogEx::OnPaint();
    }
}

HCURSOR CServerDlg::OnQueryDragIcon()
{
    return static_cast<HCURSOR>(m_hIcon);
}

void CServerDlg::OnClose()
{
    WSACleanup();
    CDialogEx::OnClose();
}

void CServerDlg::OnBnClickedListen()
{
    // 获取监听端口号
    CString portStr;
    m_Port.GetWindowText(portStr);
    int port = _ttoi(portStr);

    // 创建socket
    SOCKET listenSock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (listenSock == INVALID_SOCKET) {
        MessageBox(_T("Failed to create socket!"), _T("Error"), MB_ICONERROR | MB_OK);
        return;
    }

    // 设置本地地址
    SOCKADDR_IN localAddr;
    localAddr.sin_family = AF_INET;
    localAddr.sin_port = htons(port);
    localAddr.sin_addr.s_addr = htonl(INADDR_ANY);

    // 绑定本地地址
    if (bind(listenSock, (SOCKADDR*)&localAddr, sizeof(localAddr)) == SOCKET_ERROR) {
        MessageBox(_T("Failed to bind socket!"), _T("Error"), MB_ICONERROR | MB_OK);
        closesocket(listenSock);
        return;
    }

    // 监听
    if (listen(listenSock, SOMAXCONN) == SOCKET_ERROR) {
        MessageBox(_T("Failed to listen socket!"), _T("Error"), MB_ICONERROR | MB_OK);
        closesocket(listenSock);
        return;
    }

    // 接受连接请求
    SOCKADDR_IN clientAddr;
    int clientAddrSize = sizeof(clientAddr);
    SOCKET clientSock = accept(listenSock, (SOCKADDR*)&clientAddr, &clientAddrSize);
    if (clientSock == INVALID_SOCKET) {
        MessageBox(_T("Failed to accept connection!"), _T("Error"), MB_ICONERROR | MB_OK);
        closesocket(listenSock);
        return;
    }

    // 接收数据
    char recvBuffer[BUFFER_SIZE] = {};
    int recvLen = recv(clientSock, recvBuffer, BUFFER_SIZE, 0);
    CString recvMsg = CString(recvBuffer, recvLen);
    MessageBox(recvMsg, _T("Message Received"), MB_ICONINFORMATION | MB_OK);

    // 发送数据
    CString msg;
    m_EditBox.GetWindowText(msg);
    char* buffer = CStringA(msg).GetBuffer();
    int len = strlen(buffer);
    send(clientSock, buffer, len, 0);

    // 关闭socket
    closesocket(clientSock);
    closesocket(listenSock);
}

注意事项：

1. 在使用Winsock库之前，需要先调用WSAStartup函数进行初始化。
2. 在使用socket函数创建套接字之前，需要先指定协议族、套接字类型和协议类型。
3. 在使用bind函数将套接字绑定到本地地址之前，需要先指定本地地址的IP地址、端口号和协议族。
4. 在使用listen函数进行监听之前，需要先指定backlog参数，表示等待连接队列的最大长度。
5. 在使用accept函数接受客户端连接请求之前，需要先指定客户端地址结构体的大小。
6. 在使用send和recv函数发送和接收数据时，需要注意缓冲区的大小。