用C++建立客户端Socket，怎么用C#建立服务器端Socket进行通信，C++发数据，C#收数据。请给出示例代码。

TcpListener进行监听就可以了。
using System;
using System.IO;
using System.Net;
using System.Net.Sockets;
using System.Text;

class MyTcpListener
{
public static void Main()
{
TcpListener server=null;
try
{
// Set the TcpListener on port 13000.
Int32 port = 8000;
IPAddress localAddr = IPAddress.Parse("127.0.0.1");

// TcpListener server = new TcpListener(port);
server = new TcpListener(localAddr, port);

// Start listening for client requests.
server.Start();

// Buffer for reading data
Byte[] bytes = new Byte[4096];
String data = null;

// Enter the listening loop.
while(true)
{
Console.Write("Waiting for a connection... ");

// Perform a blocking call to accept requests.
// You could also user server.AcceptSocket() here.
TcpClient client = server.AcceptTcpClient();
Console.WriteLine("Connected!");

data = null;

// Get a stream object for reading and writing
NetworkStream stream = client.GetStream();

int i;

// Loop to receive all the data sent by the client.
while((i = stream.Read(bytes, 0, bytes.Length))!=0)
{
// Translate data bytes to a ASCII string.
data = System.Text.Encoding.ASCII.GetString(bytes, 0, i);
Console.WriteLine("Received: {0}", data);

// Process the data sent by the client.
data = data.ToUpper();

byte[] msg = System.Text.Encoding.ASCII.GetBytes(data);

// Send back a response.
stream.Write(msg, 0, msg.Length);
Console.WriteLine("Sent: {0}", data);
}

// Shutdown and end connection
client.Close();
}
}
catch(SocketException e)
{
Console.WriteLine("SocketException: {0}", e);
}
finally
{
// Stop listening for new clients.
server.Stop();
}

Console.WriteLine("\nHit enter to continue...");
Console.Read();
}
}

当然，官方的这个示例是单线程的，一次只能处理一个客户端，你可以将accept到的client扔到一个独立的线程，这样就可以多客户端并发处理了。