Can't find TcpClient.GetStream method

Question

I'm watching this video to learn the basics on C# async communication. I'm using Microsoft Visual Studio 2013.

In this line:

_networkStream.Add(client.GetStream());

I'm getting this error:

'System.Collections.Generic.List' does not contain a definition for 'GetStream and no extension method 'GetStream' accepting a first argument of type 'System.Collections.Generic.List' could be found (are you missing a using directive or an assembly reference?)

Currently here's the code I have copied while watching the tutorial:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Threading;
using System.Net;
using System.Net.Sockets;
using System.IO;

namespace Networking
{
    public class ServerManager
    {
        public int Port { get; set; }
        private TcpListener _listener;
        private List<TcpClient> _client;
        private List<NetworkStream> _networkStream;

        public ServerManager(int port)
        {
            // Assigning Port from the parameter.
            Port = port;
            // Initialize the _listener to the port specified on the constructor.
            _listener = new TcpListener(new IPEndPoint(IPAddress.Any, Port));
            // Initialize the _client sockets list.
            _client = new List<TcpClient>();
            // Initialize the _networkStream which is useful for sending and receiving data.
            _networkStream = new List<NetworkStream>();
        }

        public void Start()
        {
            // Starts the _listener to listen.
            _listener.Start();
            _listener.BeginAcceptTcpClient(new AsyncCallback(ClientConnect), null);
        }

        public void Stop()
        {
            // Closes all the _client sockets and the network stream.
            for (int i = 0; i < _client.Count; i++)
            {
                _client[i].Close();
                _networkStream[i].Close();
            }

            // Stops the listener. The socket which listens and accept incoming client sockets.
            _listener.Stop();
        }

        private void ClientConnect(IAsyncResult ar)
        {
            // When any client connects.
            // Accept the connection.
            TcpClient client = _listener.EndAcceptTcpClient(ar);
            // Add on our client list.
            _client.Add(client);
            // Add the client's stream on our network stream.
            _networkStream.Add(_client.GetStream());
            Thread threadReceive = new Thread(new ParameterizedThreadStart(ClientReceiveData), null);
            threadReceive.Start(_client.Count);

            // Accept the next connection.
            _listener.BeginAcceptTcpClient(new AsyncCallback(ClientConnect), null);
        }

        private void ClientReceiveData(object obj)
        {
            throw new NotImplementedException();
        }
    }
}

Based from MSDN, TcpClient.GetStream method is under the namespace System.Net.Sockets, which I have already included without errors. And so, why am I getting the error?

Answer 1

_client is instance of List, client is instance of TcpClient. You need to use client.GetStream() instead of _client.GetStream().

  _networkStream.Add(client.GetStream());