c# - 使用 TCP 在 C# 中实现 FTP 客户端

Question

我一直在使用 C# 中的 TCP 套接字，并且在与我设置的 FTP 服务器通信时遇到了一些问题。我最初可以连接并收到 220 消息，但是当我发送“USER nrcrast”命令时，我从未收到响应，并且 DataAvailable 属性返回 false。有人知道我做错了什么吗？到目前为止，这是我的代码:

namespace TCPClient
{
public partial class TCPClientForm : Form
{


    private TcpClient myClient;
    NetworkStream stream;

    public TCPClientForm()
    {
        InitializeComponent();
        send();

    }

    void send()
    {

        while (true)
        {
            try
            {
                myClient = new TcpClient("nrcrast.dyndns.info", 21);
                break;
            }
            catch (SocketException ex)
            {
                Console.WriteLine(ex.ToString());
            }

        }
        stream = myClient.GetStream();
        int sendOffset = 0;
        int recOffset=0;

        int dataLength;
        Byte[] receiveData = new Byte[256];


        // wait for a response
        dataLength = stream.Read(receiveData, recOffset, receiveData.Length);
        String recvdMessage = System.Text.Encoding.ASCII.GetString(receiveData, 0, dataLength);
        Console.WriteLine(recvdMessage.ToString());
         recOffset+=dataLength;


        String message = "USER nrcrast";
        Byte[] data = System.Text.Encoding.ASCII.GetBytes(message);
        stream.Write(data, 0, data.Length);
        sendOffset += data.Length;

        // wait for a response
        while (!stream.DataAvailable)
        {
        }
        dataLength = stream.Read(receiveData, 0, receiveData.Length);
        recvdMessage = System.Text.Encoding.ASCII.GetString(receiveData, 0, dataLength);
        Console.WriteLine(recvdMessage.ToString());


    }


}

Answer 1

暗杀，需要在命令末尾放回车换行

String message = "USER nrcrast\r\n";