<appSettings>
  <add key="maxQueueCount" value="10"/>
  <add key="failoverServer" value="192.168.250.113,192.168.250.141"/>
</appSettings>

Install.bat
@echo off
path %SystemRoot%\Microsoft.NET\Framework\v4.0.30319;%path%
installutil %~dp0\WindowsChat.exe
%SystemRoot%\system32\sc failure "ChatService" reset= 30 actions= restart/1000
pause
@echo on

Uninstall.bat
@echo off
path %SystemRoot%\Microsoft.NET\Framework\v4.0.30319;%path%
installutil -u %~dp0\WindowsChat.exe
pause
@echo on

namespace WindowsChat
{
  public delegate void WriteInfo(string info);

  public class SocketHelper
  {
    #region 构造函数
    public SocketHelper()
    {
    }
    public SocketHelper(WriteInfo method)
    {
      this.method = method;
    }
    #endregion

    public static Socket LocalSocket = null;
    private object lockObj = new object();
    public static List<Socket> Clients = new List<Socket>();
    private WriteInfo method = null;

    /// <summary>
    /// 创建Socket
    /// </summary>
    /// <param name="port">端口默认 11011</param>
    /// <param name="backlog">The maximum length of the pending connections queue.</param>
    /// <returns></returns>
    public Socket Create(int port = 11011, int backlog = 100)
    {
      if (LocalSocket == null)
      {
        IPEndPoint ipEndPoint = new IPEndPoint(IPAddress.Any, port);//本机预使用的IP和端口
        LocalSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
        LocalSocket.Bind(ipEndPoint);
        LocalSocket.Listen(backlog);
      }
      return LocalSocket;
    }

    /// <summary>
    /// 查找客户端连接
    /// </summary>
    /// <param name="id">标识</param>
    /// <returns></returns>
    private Socket FindLinked(string id)
    {
      foreach (var item in Clients)
      {
        if (item.RemoteEndPoint.ToString() == id)
          return item;
      }
      return null;
    }

    /// <summary>
    /// 接受远程连接
    /// </summary>
    public void Accept()
    {
      if (LocalSocket != null)
      {
        while (true)
        {
          Socket client = LocalSocket.Accept();
          Thread thread = new Thread(new ParameterizedThreadStart(Revice));
          thread.Start(client);
          WriteLog("客户端：" + client.RemoteEndPoint.ToString() + " 接入");
          lock (lockObj)
          {
            Clients.Add(client);
          }
          BroadCast("ADD|" + client.RemoteEndPoint.ToString());
        }
      }
    }

    /// <summary>
    /// 日志
    /// </summary>
    /// <param name="info">信息</param>
    private void WriteLog(string info)
    {
      using (FileStream fs = new FileStream("C:\\chatservice.txt", FileMode.Append, FileAccess.Write, FileShare.ReadWrite))
      {
        using (StreamWriter sw = new StreamWriter(fs, Encoding.UTF8))
        {
          sw.WriteLine(info);
        }
      }
      if (method != null)
      {
        method(info);
      }
    }

    /// <summary>
    /// 广播
    /// </summary>
    /// <param name="info">信息</param>
    public void BroadCast(string info)
    {
      foreach (var item in Clients)
      {
        try
        {
          item.Send(Encoding.UTF8.GetBytes(info));
        }
        catch (Exception ex)
        {
          WriteLog(item.RemoteEndPoint.ToString() + ex.Message);
          continue;
        }
      }
    }

    /// <summary>
    /// 介绍信息
    /// </summary>
    /// <param name="client"></param>
    public void Revice(object client)
    {
      Socket param = client as Socket;
      var remoteName = param.RemoteEndPoint.ToString();
      if (param != null)
      {
        int res = 0;
        while (true)
        {
          byte[] buffer = new byte[10240];
          int size = param.ReceiveBufferSize;
          try
          {
            res = param.Receive(buffer);
          }
          catch (SocketException ex)
          {
            if (ex.SocketErrorCode == SocketError.ConnectionReset)
            {
              Clients.Remove(param);
              WriteLog("客户端：" + remoteName + "断开连接1");
              BroadCast("REMOVE|" + remoteName);
              param.Close();
              return;
            }
          }

          if (res == 0)
          {
            Clients.Remove(param);
            WriteLog("客户端：" + remoteName + "断开连接2");
            BroadCast("REMOVE|" + remoteName);
            param.Close();
            return;
          }
          var clientMsg = Encoding.UTF8.GetString(buffer, 0, res);
          WriteLog(string.Format("收到客户端{0}命令：{1}", remoteName, clientMsg));
          if (clientMsg == "GETALL")
          {
            StringBuilder sb = new StringBuilder();
            foreach (var item in Clients)
            {
              sb.AppendFormat("{0}|", item.RemoteEndPoint.ToString());
            }
            param.Send(Encoding.UTF8.GetBytes("ALL|" + sb.ToString()));
          }
          else if (clientMsg == "OFFLINE")
          {
            if (Clients.Contains(param))
            {
              Clients.Remove(param);
              WriteLog("客户端：" + remoteName + "断开连接2");
              BroadCast("REMOVE|" + remoteName);
              param.Close();
              return;
            }
          }
          else if (clientMsg.StartsWith("TRANST|"))
          {
            var msgs = clientMsg.Split('|');
            var toSocket = FindLinked(msgs[1]);
            if (toSocket != null)
            {
              WriteLog(remoteName + "发给" + msgs[1] + "的消息" + msgs[2]);
              toSocket.Send(Encoding.UTF8.GetBytes("TRANSF|" + remoteName + "|" + msgs[2]));
            }
          }
        }
      }
    }
  }
}

public partial class ChatService : ServiceBase
{
    SocketHelper helper;
    Thread mainThread;

    public ChatService()
    {
      InitializeComponent();
    }

    protected override void OnStart(string[] args)
    {
      if (helper == null)
      {
        helper = new SocketHelper();
      }
      helper.Create();
      mainThread = new Thread(new ThreadStart(helper.Accept));
      mainThread.IsBackground = true;
      mainThread.Start();
    }

    protected override void OnStop()
    {
      helper.BroadCast("SHUTDOWN");
    }
}