How send a command from Server (using a List of connections) to Client after connection established?

问题

I have these two classes that is part of my Server application (desktop) and need send a command back to Client after connection was established.

When i try make this way:

clients[i].Send("info");

the Send() routine (of Listener.cs) is accessible, but i have this following sintaxe error:

How solve this?

Listener.cs

using System;
using System.Collections.Generic;
using System.Text;
using System.Net;
using System.Net.Sockets;

class Listener
{
    Socket s;
    string IP;
    public List<Info> clients;

    public delegate void ReceivedEventHandler(Listener l, Info i, string received);
    public event ReceivedEventHandler Received;
    public delegate void DisconnectedEventHandler(Listener l, Info i);
    public event DisconnectedEventHandler Disconnected;

    bool listening = false;
    public Listener()
    {
        clients = new List<Info>();
        s = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
    }

    public bool Running
    {
        get { return listening; }
    }

    public void BeginListen(int port)
    {
        s.Bind(new IPEndPoint(IPAddress.Any, port));
        s.Listen(100);
        s.BeginAccept(new AsyncCallback(AcceptCallback), s);
        listening = true;
    }

    public void StopListen()
    {
        if (listening == true)
        {
            s.Close();
        }
    }

    void AcceptCallback(IAsyncResult ar)
    {
        Socket handler = (Socket)ar.AsyncState;
        Socket sock = handler.EndAccept(ar);
        Info i = new Info(sock);
        clients.Add(i);

        Console.WriteLine("New Connection: " + i.ID.ToString());
        clients[i].Send("info");
        sock.BeginReceive(i.buffer, 0, i.buffer.Length, SocketFlags.None, new AsyncCallback(ReadCallback), i);
        handler.BeginAccept(new AsyncCallback(AcceptCallback), handler);
    }

    void ReadCallback(IAsyncResult ar)
    {
        Info i = (Info)ar.AsyncState;
        try
        {
            int rec = i.sock.EndReceive(ar);
            if (rec != 0)
            {
                string data = Encoding.ASCII.GetString(i.buffer, 0, rec);
                Received(this, i, data);
            }
            else
            {
                Disconnected(this, i);
                return;
            }

            i.sock.BeginReceive(i.buffer, 0, i.buffer.Length, SocketFlags.None, new AsyncCallback(ReadCallback), i);
        }
        catch
        {
            Disconnected(this, i);
            i.sock.Close();
            clients.Remove(i);
        }
    }
}

Info.cs

using System;
using System.Collections.Generic;
using System.Text;
using System.Net;
using System.Net.Sockets;

public class Info
{
    public Socket sock;
    public Guid ID;
    public string RemoteAddress;
    public byte[] buffer = new byte[8192];

    public Info(Socket sock)
    {
        this.sock = sock; 
        ID = Guid.NewGuid(); 
        RemoteAddress = sock.RemoteEndPoint.ToString(); 
    }

    public void Send(string data)
    {
        byte[] buffer = Encoding.ASCII.GetBytes(data);
        sock.BeginSend(buffer, 0, buffer.Length, SocketFlags.None, new AsyncCallback((ar) =>
        {
            sock.EndSend(ar);
        }), buffer);
    }
}

Project of reference

回答1:

clients[i].Send("info");

This statement is incorrect. The variable 'i' refers to an instance of the Info class. It is not an integer index into the list. The correct call would be as below.

i.Send("info");

来源：https://stackoverflow.com/questions/52910928/how-send-a-command-from-server-using-a-list-of-connections-to-client-after-con