[网络协议](C#)TCP 异步重连机制

• 在csdn找了很久也没有找到合适的，找半天demo运行还是有问题的，真是服了，在这里记录自己的心得，如果有问题的话，麻烦指正。

• 发送检测tcp连接是否成功，不成功则重连。

• 加载缓冲区，当连接不成功时候，发送字符将会进行保存，连接成功之后以500ms的速度依次发送。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

using System.Collections;
using System.Net.Sockets;
using System.Diagnostics;
using System.IO;
using System.Net;
using System.Timers;

namespace SocketProject
{
    class TcpClient
    {
        private int port;
        private string name;
        private List<string> stringList = new List<string>();
        private static readonly TcpClient singleInstance = new TcpClient();
        Socket tcpClient;
        private Timer timer;

        //单例模式
        public static TcpClient GetInstance
        {
            get
            {
                return singleInstance;
            }
        }

        public TcpClient()
        {

        }

        public void TryToConnet(string Name, int Port)
        {
            port = Port;
            name = Name;

            if (null != timer)
            {
                timer.Stop();
            }

            if (null != tcpClient)
            {
                tcpClient.Close();
                tcpClient = null;
            }
            tcpClient = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            tcpClient.BeginConnect(name, port, Connect, null);
        }

        private void Connect(IAsyncResult ar)
        {
            try
            {
                tcpClient.EndConnect(ar);
                if (tcpClient.Connected)
                {
                    Console.WriteLine($"Connected Succeed");
                    if (timer != null)
                    {
                        timer.Start();
                    }
                    else
                    {
                        //设置定时间隔(毫秒为单位)
                        int interval = 500;
                        timer = new System.Timers.Timer(interval);
                        //设置执行一次（false）还是一直执行(true)
                        timer.AutoReset = true;
                        //设置是否执行System.Timers.Timer.Elapsed事件
                        timer.Enabled = true;
                        //绑定Elapsed事件
                        timer.Elapsed += new System.Timers.ElapsedEventHandler(TimeOut);

                        timer.Start();
                    }
                }
            }

            catch (SocketException ex)
            {
                Console.WriteLine($"Message = {ex.Message} Error code = {ex.ErrorCode}");
                TryToConnet(name, port);
            }
        }


        //连接完成将缓冲区的数据发送到服务器
        private void TimeOut(object sender, ElapsedEventArgs e)
        {
            if (stringList.Count > 0)
            {
                SendMsg(stringList[0]);
            }
            else
            {
                timer.Stop();
            }
        }

        public void Close()
        {

            if (tcpClient != null && tcpClient.Connected)
            {
                tcpClient.Close();
            }
        }

        //判断连接断开
        bool IsConnected()
        {
            bool isConnected = true;
            try
            {
                // Detect if client disconnected
                if (tcpClient != null && tcpClient.Poll(0, SelectMode.SelectRead))
                {
                    byte[] buff = new byte[1];
                    if (tcpClient.Receive(buff, SocketFlags.Peek) == 0)
                    {
                        // Client disconnected
                        isConnected = false;
                    }
                }

            }
            catch (SocketException se)
            {
                Console.WriteLine($" se.ErrorCode == {se.ErrorCode} se.Message == {se.Message}");
                isConnected = false;
            }
            return isConnected;
        }

        //发送消息和重连
        public void SendMsg(string msg)
        {
            if (!stringList.Contains(msg))
            {
                stringList.Add(msg);
            }

            if (null == tcpClient || !tcpClient.Connected)
            {
                return;
            }

            try
            {
                if (IsConnected())
                {
                    byte[] msgBytes = Encoding.UTF8.GetBytes(stringList[0]);
                    tcpClient.Send(msgBytes);
                    stringList.RemoveAt(0);
                }
                else
                {
                    TryToConnet(name, port);
                }
            }
            catch (SocketException e)
            {
                Console.WriteLine("{0} Error code: {1}.", e.Message, e.ErrorCode);
            }
            catch (ObjectDisposedException obj)
            {
                Console.WriteLine(string.Format("ObjectDisposedException：{0}", obj.Message));
            }
        }
    }
}