C#异步TCP客户端连接

前言：C#平常的TCP客户端连接不稳定，时常断线，这时我使用了异步连接之后就没有断线了。

旧连接代码：

//创建用于通讯的socket
 PlcClass.Instance.socketsend = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
 IPAddress ip = IPAddress.Parse(BaseData.Instance.tcp_ip);
 IPEndPoint port = new IPEndPoint(ip, Convert.ToInt32(BaseData.Instance.tcp_port));
 //连接对应的端口
 PlcClass.Instance.socketsend.Connect(port);
 // 接收信息
 byte[] buffer = new byte[1024 * 1024 * 2];
 int i = socketsend.Receive(buffer);
 string str = Encoding.UTF8.GetString(buffer, 0, i);
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新异步连接代码

TcpClient tcpClient;
byte[] ReadBytes = new byte[1024 * 1024];
//连接服务器
public void ConnectServer(string ip, int port)//填写服务端IP与端口
{
    try
    {
        tcpClient = new System.Net.Sockets.TcpClient();//构造Socket
        tcpClient.BeginConnect(IPAddress.Parse(ip), port, Lianjie, null);//开始异步
    }
    catch (Exception e)
    {
        MessageBox.Show(e.Message);
    }
}

//连接判断
void Lianjie(IAsyncResult ar)
{
    try
    {
        if (!tcpClient.Connected)
        {
            IPAddress ip = IPAddress.Parse(BaseData.Instance.tcp_ip);
            tcpClient.BeginConnect(ip, Convert.ToInt32(BaseData.Instance.tcp_port), Lianjie, null);
        }
        else
        {
            tcpClient.EndConnect(ar);//结束异步连接
            tcpClient.GetStream().BeginRead(ReadBytes, 0, ReadBytes.Length, ReceiveCallBack, null);
        }
    }
    catch (Exception ex)
    {
        MessageBox.Show("连接失败：" + ex.Message);
    }
   
}


//接收消息
void ReceiveCallBack(IAsyncResult ar)
{
    try
    {
        int len = tcpClient.GetStream().EndRead(ar);//结束异步读取
        if (len > 0)
        {
            string str = Encoding.UTF8.GetString(ReadBytes, 0, len);
            str = Uri.UnescapeDataString(str);
            ,...逻辑处理....
            tcpClient.GetStream().BeginRead(ReadBytes, 0, ReadBytes.Length, ReceiveCallBack, null);
        }
        else
        {
            tcpClient = null;
            ConnectServer(BaseData.Instance.tcp_ip, Convert.ToInt32(BaseData.Instance.tcp_port));
        }
    }
    catch (Exception e)
    {
        MessageBox.Show(e.Message);
    }
}

//发送消息
public void SendMsg(string msg)
{
    try
    {
        byte[] msgBytes = Encoding.UTF8.GetBytes(msg);
        tcpClient.GetStream().BeginWrite(msgBytes, 0, msgBytes.Length, (ar) => {
            tcpClient.GetStream().EndWrite(ar);//结束异步发送
        }, null);//开始异步发送
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message);
    }
   
}

/// <summary>
/// 断开连接
/// </summary>
public void TcpClose()
{
    try
    {
        if (tcpClient != null && tcpClient.Client.Connected)
            tcpClient.Close();
        if (!tcpClient.Client.Connected)
        {
            tcpClient.Close();//断开挂起的异步连接
        }
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message);
    }
   
}
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