在C#中可以使用DotNetty來實現TCP通信，以下是一個簡單的示例代碼：

using DotNetty.Buffers;
using DotNetty.Codecs;
using DotNetty.Common.Concurrency;
using DotNetty.Transport.Bootstrapping;
using DotNetty.Transport.Channels;
using DotNetty.Transport.Channels.Sockets;
using System;
using System.Net;
using System.Text;
using System.Threading.Tasks;

class Program
{
    static async Task Main(string[] args)
    {
        var group = new MultithreadEventLoopGroup();

        var bootstrap = new ServerBootstrap();
        bootstrap
            .Group(group)
            .Channel<TcpServerSocketChannel>()
            .Option(ChannelOption.SoBacklog, 100)
            .Handler(new LoggingHandler(LogLevel.INFO))
            .ChildHandler(new ActionChannelInitializer<ISocketChannel>(channel =>
            {
                IChannelPipeline pipeline = channel.Pipeline;

                pipeline.AddLast(new LengthFieldBasedFrameDecoder(ByteOrder.BigEndian, int.MaxValue, 0, 4, 0, 4, true));
                pipeline.AddLast(new LengthFieldPrepender(ByteOrder.BigEndian, 4, 0, false));
                pipeline.AddLast(new StringEncoder(Encoding.UTF8));
                pipeline.AddLast(new StringDecoder(Encoding.UTF8));
                pipeline.AddLast(new SimpleServerHandler());
            }));

        IChannel boundChannel = await bootstrap.BindAsync(IPAddress.Parse("127.0.0.1"), 8888);
        Console.ReadLine();

        await boundChannel.CloseAsync();
        await group.ShutdownGracefullyAsync(TimeSpan.FromMilliseconds(100), TimeSpan.FromSeconds(1));
    }
}

public class SimpleServerHandler : SimpleChannelInboundHandler<string>
{
    protected override void ChannelRead0(IChannelHandlerContext ctx, string msg)
    {
        Console.WriteLine($"Received from client: {msg}");

        // Echo back to client
        ctx.WriteAndFlushAsync(msg);
    }

    public override void ExceptionCaught(IChannelHandlerContext ctx, Exception cause)
    {
        Console.WriteLine($"Exception: {cause}");
        ctx.CloseAsync();
    }
}

以上代碼是一個簡單的TCP服務器示例，它監聽本地IP地址127.0.0.1的8888端口，并使用DotNetty來處理TCP通信。在SimpleServerHandler類中，實現了處理接收到的消息和異常的方法。可以根據實際需求修改代碼來實現自定義的TCP通信邏輯。