OK。把邮件发送类转过来，让大家看看

using System;
using System.Text;
using System.IO;
using System.Net;
using System.Net.Sockets;
namespace Blood.Com.ClassLib
{    
    /// <summary>
    /// TcpClient派生类，用来进行SMTP服务器的连接工作
    /// </summary>
    public class SMTPClient : TcpClient
    {
        public bool isConnected()
        {
       return Active;
        }
        public void SendCommandToServer(string Command)
        {
       NetworkStream ns = this.GetStream() ;
       byte[]    WriteBuffer ;
       WriteBuffer = new byte[1024] ;
       WriteBuffer = Encoding.Default.GetBytes(Command) ;
       ns.Write(WriteBuffer,0,WriteBuffer.Length);
       return    ;
        }    
        public string GetServerResponse()
        {

补充：asp.net教程,远程及网络应用