背景：跟上海的公司大佬一起开发一个项目，他用 c++ 写后端 我用 c# 写前端，用 udp 通信，我这边能收发消息，可就是怎么样都用收到的消息跟另一个字符判断不了相等，麻烦了一天多的　Ｂｕｇ，头都大佬

用 list 遍历出来接到的字节：

 byte[] data = state.UDPClient.EndReceive(ar, ref ipep);
            //这里可以做一个数据检查 如：void CheckData(data)
            string msgStr = Encoding.UTF8.GetString(data, 0, data.Length);
            List<char> list = new List<char>();
            foreach (char s in msgStr)
            {
                if (s != ' ')
                {
                    list.Add(s);
                }
            }
            msgStr = list.ToString();
            foreach (var item in list)
            {
                print("list char" + item);
            }

原理：是c+＋　在发送消息的时候　会在字节后面默认加一个　＼０　的字节，如果用ｃ＃接收消息，可以将最后一个字符给截掉

receiveData = client.Receive(ref remotePoint);//接收数据 
            receiveString = Encoding.Default.GetString(receiveData);
            string s = receiveString.Substring(0, receiveString.Length - 1);

unity UDP 异步接收消息代码：

using UnityEngine;
using System.Net;
using System.Net.Sockets;
using System.Threading;
using System;
using System.Text;
using System.Collections.Generic;
using UnityEngine.SceneManagement;

public class UDPAsyncRecvive : MonoBehaviour
{
    private bool ChangeScene;
    string receiveString = null;
    void Start()
    {
        ThreadRecvive();
    }



    void Update()
    {
        if (ChangeScene)
        {
            ChangeScene = false;
            receiveString = null;
            SceneManager.LoadScene("Scene0-ZLoadingScene");
            Debug.Log("切换场景");
        }
    }
    /// <summary>
    /// 开始线程接收
    /// </summary>
    private void ThreadRecvive()
    {
        //开一个新线程接收UDP发送的数据
        new Thread(delegate ()  //delegate()也可写成 ()=>
        {
            IPEndPoint ipep = new IPEndPoint(IPAddress.Any, 9000);
            UdpClient udp = new UdpClient(ipep);
            UDPState state = new UDPState(ipep, udp);
            udp.BeginReceive(CallBackRecvive, state); //异步接收
        })
        { IsBackground = true }.Start(); //设置为后台线程，并开启线程
    }

    /// <summary>
    /// 异步接收回调
    /// </summary>
    /// <param name="ar"></param>
    private void CallBackRecvive(IAsyncResult ar)
    {
        UDPState state = ar.AsyncState as UDPState;
        if (state != null)
        {
            IPEndPoint ipep = state.IPEP;
            //这里接收到数据后，应该做数据完整检查，这里只是单纯做一个接收
            byte[] data = state.UDPClient.EndReceive(ar, ref ipep);
            //这里可以做一个数据检查 如：void CheckData(data)
            string receiveString = Encoding.UTF8.GetString(data, 0, data.Length);
            string msgStr = receiveString.Substring(0, receiveString.Length - 1);
            if (msgStr.Trim().CompareTo("STATE-END") == 0)
            {
                ChangeScene = true;
                Debug.Log("切换场景");
            }

            //继续接收下一条消息
            state.UDPClient.BeginReceive(CallBackRecvive, state);
        }
    }

}

public class UDPState
{
    private UdpClient udpClient;

    public UdpClient UDPClient
    {
        get { return udpClient; }
    }

    private IPEndPoint ipep;
    public IPEndPoint IPEP
    {
        get { return ipep; }
    }

    //构造函数
    public UDPState(IPEndPoint ipep, UdpClient udpClient)
    {
        this.ipep = ipep;
        this.udpClient = udpClient;
    }
}