请问怎么编写C#用vs studio 2015连接上云服务器呢？

你了解TCP/IP socket编程相关知识吗？

网页链接

首先你要在云服务器上运行一个服务器程序，然后在本机运行客户端程序，两者通过TCP协议通讯交换数据(即你所说的连上云服务器)。

最简单的服务器程序：

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 = 13000; 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[256];
  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();

}
} 最简单的客户端：

static void Connect(String server, String message) { try { // Create a TcpClient. // Note, for this client to work you need to have a TcpServer // connected to the same address as specified by the server, port // combination. Int32 port = 13000; TcpClient client = new TcpClient(server, port);

// Translate the passed message into ASCII and store it as a Byte array.
Byte[] data = System.Text.Encoding.ASCII.GetBytes(message);         
// Get a client stream for reading and writing.
//  Stream stream = client.GetStream();

NetworkStream stream = client.GetStream();
// Send the message to the connected TcpServer. 
stream.Write(data, 0, data.Length);
Console.WriteLine("Sent: {0}", message);         
// Receive the TcpServer.response.

// Buffer to store the response bytes.
data = new Byte[256];
// String to store the response ASCII representation.
String responseData = String.Empty;
// Read the first batch of the TcpServer response bytes.
Int32 bytes = stream.Read(data, 0, data.Length);
responseData = System.Text.Encoding.ASCII.GetString(data, 0, bytes);
Console.WriteLine("Received: {0}", responseData);         
// Close everything.
stream.Close();         
client.Close();         

} catch (ArgumentNullException e) { Console.WriteLine("ArgumentNullException: {0}", e); } catch (SocketException e) { Console.WriteLine("SocketException: {0}", e); }

Console.WriteLine("\n Press Enter to continue..."); Console.Read(); }