c# socket通信 传输文件

在C#中，使用Socket进行文件传输通常是通过分块读写的方式来实现的，因为一次完整的文件可能会非常大，不适合一次性发送。这里是一个简单的示例，展示如何使用TCP协议进行文件上传和下载：

### 文件上传:

1. **打开套接字并设置服务器端口**:

TcpListener listener = new TcpListener(IPAddress.Any, PortNumber);
listener.Start();

2. **接受连接并处理文件发送**:

Socket client = listener.AcceptSocket();
using (FileStream fileStream = File.OpenRead(FileToUpload))
{
    byte[] buffer = new byte[BufferSize];
    int bytesRead;
    while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) > 0)
    {
        client.Send(buffer, bytesRead);
    }
}
fileStream.Close();
client.Close();

### 文件下载:

1. **服务器创建套接字并监听客户端请求**:

TcpClient client = await listener.AcceptTcpClientAsync();

2. **创建文件流准备接收文件**:

NetworkStream networkStream = client.GetStream();
using (FileStream outputStream = File.Create(DownloadPath))
{
    byte[] buffer = new byte[BufferSize];
    int bytesReceived;
    while ((bytesReceived = networkStream.Read(buffer, 0, buffer.Length)) > 0)
    {
        outputStream.Write(buffer, 0, bytesReceived);
    }
}
networkStream.Close();
client.Close();