C# Socket 入门4 UPD 发送结构体

今天我们来学 socket  发送结构体

1. 先看要发送的结构体

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

namespace Lin.p2p.Mo
{
    /// <summary>
    /// 通信消息格式
    /// </summary>
    [Serializable]
    [StructLayout(LayoutKind.Sequential, Pack = 1)]
    public struct CP2PMessage
    {
        public sbyte nMessageTypes;
        public int Value;
    }
}

2. 请看服务端

using System;
using System.Collections.Generic;
using System.Text;
using System.Net.Sockets;
using System.Net;
using Lin.p2p;
using Lin.p2p.Mo;

namespace ConsoleApplication1
{
    class Program
    {
        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("This is a Server, host name is {0}", Dns.GetHostName());
            Console.WriteLine("Waiting for a client...");

            // 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)Tool.BytesToStruct(buffer, msg.GetType());

            Console.WriteLine("接收的值为:{0}", msg.Value);

            Console.ReadKey();
        }
    }
}

2.其中重要的一段就是把  结构体转为 byte数组

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

namespace Lin.p2p.Mo
{
    public class Tool
    {
        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. 最后看客户端

            // 1.创建套节字
             m_s = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);

            // 2.填写服务器IP
            IPAddress ip = IPAddress.Parse("127.0.0.1");
            IPEndPoint ipe = new IPEndPoint(ip, 4321);


            //向服务器发送本用户信息
             CP2PMessage msg = new CP2PMessage();
            msg.nMessageTypes = (sbyte)Cmd.UserLogin;
            msg.Value = 10;

            var buffer = Fun.StructToBytes(msg);

            m_s.SendTo(buffer, buffer.Length, SocketFlags.None, ipe);

            Console.ReadKey();

4. 哈哈，当然， 效果来也~~