C# Socket 入门5 UPD 结构体 与 C++ 通信

这篇文章本来是星期五晚写好了， 因6日去旅游了， 没来得急发上来

1. 同样， 我们先看看这一个比简单的 结构体

using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;

namespace CSharp_Socket_5
{
    /// <summary>
    /// 通信消息格式
    /// </summary>
    [Serializable]
    [StructLayout(LayoutKind.Sequential, Pack = 1)]
    public struct CP2PMessage
    {
        public ushort id;
    }
}

C++ 版本

struct CP2PMessage
{
    WORD id;
};

2. C# 服务端，  和之前的一样滴~~  看来是不是很亲切也~

using System;
using System.Collections.Generic;
using System.Text;
using System.Net.Sockets;
using System.Net;
using System.Runtime.InteropServices;

namespace CSharp_Socket_5
{
    class Program
    {
        /// <summary>
        /// 服务端
        /// </summary>
        /// <param name="args"></param>
        static void Main(string[] args)
        {
            // 1.创建套节字
            Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);

            // 2.填充IP
            IPEndPoint ipe = new IPEndPoint(IPAddress.Any, 4321);

            // 3.绑定
            socket.Bind(ipe);

            // 等待客户机连接
            Console.WriteLine("这个服务器, host name is {0}", Dns.GetHostName());
            Console.WriteLine("等待客户端连接....");

            // 4.得客户机IP
            IPEndPoint sender = new IPEndPoint(IPAddress.Any, 0);
            EndPoint remote = (EndPoint)sender;

            // 5.接收客户机数据
            byte[] buffer = new byte[1024];
            socket.ReceiveFrom(buffer, ref remote);

            CP2PMessage msg = new CP2PMessage();
            msg = (CP2PMessage)BytesToStruct(buffer, msg.GetType());

            Console.WriteLine("接C++收的值为:{0}", msg.id);

            Console.ReadKey();

        }

        public static byte[] StructToBytes(object obj)
        {
            int size = Marshal.SizeOf(obj);
            byte[] bytes = new byte[size];
            IntPtr structPtr = Marshal.AllocHGlobal(size); //分配结构体大小的内存空间
            Marshal.StructureToPtr(obj, structPtr, false); //将结构体拷到分配好的内存空间
            Marshal.Copy(structPtr, bytes, 0, size);       //从内存空间拷到byte数组
            Marshal.FreeHGlobal(structPtr);                //释放内存空间
            return bytes;
        }

        public static object BytesToStruct(byte[] bytes, Type type)
        {
            int size = Marshal.SizeOf(type);
            if (size > bytes.Length)
                return null;
            IntPtr structPtr = Marshal.AllocHGlobal(size); //分配结构大小的内存空间
            Marshal.Copy(bytes, 0, structPtr, size);       //将byte数组拷到分配好的内存空间
            object obj = Marshal.PtrToStructure(structPtr, type);
            Marshal.FreeHGlobal(structPtr);
            return obj;
        }
    }
}

3. 重点了，，C++ 客户端

#include <winsock2.h>
#include <stdio.h>
#pragma comment(lib, "WS2_32.lib")

struct CP2PMessage
{
    WORD id;
};

void main()
{
    //初始化 WS2_32.dll
    WSADATA wsaData;
    ::WSAStartup(MAKEWORD(2,2), & wsaData);

    // 1.创建套节字
    SOCKET s = ::socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);

    // 2.填写服务器IP
    sockaddr_in sin;
    sin.sin_family = AF_INET;
    sin.sin_port = ::htons(4321);
    sin.sin_addr.S_un.S_addr = ::inet_addr("127.0.0.1");

    // 3. 向服务器发送消息
    CP2PMessage msg;
    msg.id = 10;

    ::sendto(s, (char*)&msg, sizeof(msg), 0, (sockaddr*)&sin, sizeof(sin));
}

4. 完成了，，，这么， 请看效果图！！