C# TCP服务异步向客服端传输多个文件到客服端保存到本地

在C#中，通过TCP协议创建一个异步的文件传输服务，你可以使用`Socket`或`.NET Core`的`System.Net.Sockets`库。下面是一个简化的示例，展示了如何使用`TcpListener`监听客户端连接，并通过`FileStream`异步发送多个文件：

using System;
using System.IO;
using System.Net;
using System.Net.Sockets;

class FileServer
{
    private TcpListener listener;
    private int port = 8000; // 设置监听端口

    public async Task Start()
    {
        listener = new TcpListener(IPAddress.Any, port);
        await listener.StartAsync();

        Console.WriteLine($"TCP server started on {listener.LocalEndpoint}");

        while (true)
        {
            var client = await listener.AcceptTcpClientAsync();
            Console.WriteLine($"Accepted connection from: {client.Client.RemoteEndPoint}");

            await HandleFileTransfer(client);
        }
    }

    private async Task HandleFileTransfer(TcpClient client)
    {
        try
        {
            using Stream inputStream = client.GetStream();
            string[] filesToSend = { "file1.txt", "file2.jpg" }; // 文件列表

            foreach (string file in filesToSend)
            {
                byte[] buffer = File.ReadAllBytes(file);
                await SendFileStream(inputStream, buffer, file);
            }

            Console.WriteLine("Files sent successfully.");
        }
        catch (Exception ex)
        {
            Console.WriteLine($"Error: {ex.Message}");
        }
        finally
        {
            client.Close();
        }
    }

    private async Task SendFileStream(Stream outputStream, byte[] data, string fileName)
    {
        using (MemoryStream memoryStream = new MemoryStream(data))
        using (NetworkStream networkStream = new NetworkStream(outputStream))
        {
            ASCIIEncoding asciiEncoding = new ASCIIEncoding();
            string filePathLength = asciiEncoding.GetString(BitConverter.GetBytes(data.Length));
            await networkStream.WriteAsync(asciiEncoding.GetBytes(filePathLength), 0, filePathLength.Length);

            await networkStream.WriteAsync(memoryStream.ToArray(), 0, data.Length);
        }
    }

    // 主函数启动服务
    static void Main(string[] args)
    {
        var server = new FileServer();
        server.Start().GetAwaiter().GetResult();
    }
}

在这个例子中，服务器首先接收来自客户端的连接，然后遍历文件列表并逐个读取每个文件的内容，将其转换为字节数组，再通过网络流异步发送给客户端。每个文件之前会先发送一个表示文件长度的信息。