一、通讯基类
using System;
using System.Net.Sockets;
using System.Net ;
using System.IO ;
using System.Windows.Forms;
using System.Text;

 namespace BaseClass
{
     ///<summary>
     /// 传送信息的格式为 给定长度的命令部分+给定长度的命令注释部分+可变长度的长度信息+可变长度的信息部分
     ///</summary>
     publicclass CommunClass
     {
         public CommunClass()
         {
              //
              // TODO: 在此处添加构造函数逻辑
              //
         }
         ///<summary>
         /// 命令部分的长度
         ///</summary>
          privatestaticreadonlyint CMDLEN = 50 ;
         ///<summary>
         /// 命令注释部分的长度
         ///</summary>
          privatestaticreadonlyint DESCLEN = 100 ;
         ///<summary>
         /// 可变长度的长度信息部分所占的字节数
         ///</summary>
          privatestaticreadonlyint DYNAMICLENGTHLEN = 10 ;
         ///<summary>
         /// 每次处理可变信息部分的长度
         ///</summary>
          privatestaticreadonlyint DEALLEN = 1024 ;            
         ///<summary>
         /// /应答的最大长度
         ///</summary>
          privatestaticreadonlyint RESPONLEN = 20 ;
         ///<summary>
         /// 用于填充命令或注释不足长度部分的字符
         ///</summary>   
          privatestaticreadonlychar FILLCHAR = '^' ;

          ///<summary>
         /// 成功发送一部分数据后的回调方法(也可以认为是触发的事件，但严格来说还不是)
         ///</summary>
          publicdelegatevoid OnSend(int iTotal,int iSending) ;

          ///<summary>
         /// 根据给定的服务器和端口号建立连接
         ///</summary>
         ///<param name="strHost">服务器名</param>
         ///<param name="iPort">端口号</param>
         ///<returns></returns>
         publicstatic Socket ConnectToServer(string strHost,int iPort)
         {            
              try
              {
                   IPAddress ipAddress = Dns.Resolve(strHost).AddressList[0];
                   IPEndPoint ipPoint = new IPEndPoint(ipAddress,iPort) ;

                    Socket s = new Socket(AddressFamily.InterNetwork,SocketType.Stream,ProtocolType.Tcp) ;
                   s.Connect(ipPoint) ;
                   return s ;
              }
              catch (Exception e)
              {
                   throw (new Exception("建立到服务器的连接出错" + e.Message)) ;
              }
         }
         ///<summary>
         /// 将文本写到Socket中
         ///</summary>
         ///<param name="s">要发送信息的Socket</param>
         ///<param name="strInfo">要发送的信息</param>
         ///<returns>是否成功</returns>
         publicstaticbool WriteTextToSocket(Socket s,string strInfo)
         {
              byte [] buf = Encoding.UTF8.GetBytes(strInfo) ;
              try
              {
                   s.Send(buf,0,buf.Length,SocketFlags.None) ;
                   returntrue ;
              }
              catch(Exception err)
              {
                   MessageBox.Show("发送文本失败！"+err.Message) ;
                   returnfalse ;
              }
         }
         ///<summary>
         /// 将命令文本写到Socket中
         ///</summary>
         ///<param name="s">要发送命令文本的Socket</param>
         ///<param name="strInfo">要发送的命令文本</param>
         ///<returns>是否成功</returns>
         publicstaticbool WriteCommandToSocket(Socket s,string strCmd)
         {
              if (strCmd == "")
                   strCmd = "NOP" ;
              strCmd = strCmd.PadRight(CMDLEN,FILLCHAR) ;
              return WriteTextToSocket(s,strCmd) ;         
         }
         ///<summary>
         /// 将命令注释写到Socket中
         ///</summary>
         ///<param name="s">要发送命令注释的Socket</param>
         ///<param name="strInfo">要发送的命令注释</param>
         ///<returns>是否成功</returns>
         publicstaticbool WriteCommandDescToSocket(Socket s,string strDesc)
         {
              if (strDesc == "")
                   strDesc = "0" ;
              strDesc = strDesc.PadRight(DESCLEN,FILLCHAR) ;
              return WriteTextToSocket(s,strDesc) ;             
         }
         ///<summary>
         /// 发送可变信息的字节数
         ///</summary>
         ///<param name="s">要发送字节数的Socket</param>
         ///<param name="iLen">字节数</param>
         ///<returns>是否成功</returns>
         publicstaticbool WriteDynamicLenToSocket(Socket s,int iLen)
         {            
              string strLen = iLen.ToString().PadRight(DYNAMICLENGTHLEN,FILLCHAR) ;
              return WriteTextToSocket(s,strLen) ;         
         }
         ///<summary>
         /// 将缓存的指定部分发送到Socket
         ///</summary>
         ///<param name="s">要发送缓存的Socket</param>
         ///<param name="buf">要发送的缓存</param>
         ///<param name="iStart">要发送缓存的起始位置</param>
         ///<param name="iCount">要发送缓存的字节数</param>
         ///<param name="iBlock">每次发送的字节说</param>
         ///<param name="SendSuccess">每次发送成功后的回调函数</param>
         ///<returns>是否发送成功</returns>
         publicstaticbool WriteBufToSocket(Socket s,byte [] buf,int iStart,int iCount,int iBlock,OnSend SendSuccess)
         {   
              int iSended = 0 ;
              int iSending = 0 ;
              while(iSended<iCount)
              {
                   if (iSended + iBlock <= iCount)
                        iSending = iBlock ;
                   else
                        iSending = iCount - iSended ;
                   s.Send(buf,iStart+iSended,iSending,SocketFlags.None) ;                     
                   iSended += iSending ;
                   if (ReadResponsionFromSocket(s)=="OK")
                       if (SendSuccess != null)
                        SendSuccess(iCount,iSended) ;
                   else
                       returnfalse;
              }
             returntrue ;                      
         }
         ///<summary>
         /// 将长度不固定文本发送到socket
         ///</summary>
         ///<param name="s">要发送文本的Socket</param>
         ///<param name="strText">要发送的文本</param>
         ///<param name="OnSendText">成功发送一部分文本后的回调函数</param>
         ///<param name="settextlen">得到文本长度的回调函数</param>
         ///<returns></returns>
         publicstaticbool WriteDynamicTextToSocket(Socket s,string strText,
              OnSend OnSendText)
         {
              byte [] buf = Encoding.UTF8.GetBytes(strText) ;

                            int iLen = buf.Length ;
              try
              {
                   WriteDynamicLenToSocket(s,iLen) ;
                   return WriteBufToSocket(s,buf,0,iLen,DEALLEN,OnSendText) ;
              }
              catch(Exception err)
              {
                   MessageBox.Show("发送文本失败！"+err.Message) ;
                   returnfalse ;
              }
         }
         ///<summary>
         /// 将文件写到Socket
         ///</summary>
         ///<param name="s">要发送文件的Socket</param>
         ///<param name="strFile">要发送的文件</param>
         ///<returns>是否成功</returns>
         publicstaticbool WriteFileToSocket(Socket s,string strFile,
              OnSend OnSendFile)
         {
              FileStream fs = new FileStream(strFile,FileMode.Open,FileAccess.Read,FileShare.Read) ;
              int iLen = (int)fs.Length ;
              WriteDynamicLenToSocket(s,iLen) ;
              byte [] buf = newbyte[iLen] ;
              try
              {
                   fs.Read(buf,0,iLen) ;
                   return WriteBufToSocket(s,buf,0,iLen,DEALLEN,OnSendFile) ;
              }
              catch(Exception err)
              {
                   MessageBox.Show("发送文件失败！"+err.Message) ;
                   returnfalse ;
              }
              finally
              {
                   fs.Close() ;
              }             
         }
         ///<summary>
         /// 对方对自己消息的简单回应
         ///</summary>
         ///<param name="s"></param>
         ///<returns></returns>
         publicstaticstring ReadResponsionFromSocket( Socket s)
         {
              byte [] bufCmd = newbyte[RESPONLEN] ;
              int iCount = s.Receive(bufCmd) ;
              string strRespon = Encoding.UTF8.GetString(bufCmd,0,iCount) ;
              return strRespon ;
         }
         ///<summary>
         /// 从Socket读取命令
         ///</summary>
         ///<param name="s">要读取命令的Socket</param>
         ///<returns>读取的命令</returns>
         publicstaticstring ReadCommandFromSocket( Socket s)
         {                 
              byte [] bufCmd = newbyte[CMDLEN] ;
              int iCount = s.Receive(bufCmd,0,CMDLEN,SocketFlags.Partial) ;
              string strCommand = Encoding.UTF8.GetString(bufCmd,0,CMDLEN) ;
              return strCommand = strCommand.TrimEnd(FILLCHAR) ;
         }
         ///<summary>
         /// 读取命令注释
         ///</summary>
         ///<param name="s">要读取命令注释的Socket</param>
         ///<returns>读取的命令注释</returns>
         publicstaticstring ReadCommandDescFromSocket( Socket s)
         {                 
              byte [] bufCmd = newbyte[DESCLEN] ;
              int iCount = s.Receive(bufCmd,0,DESCLEN,SocketFlags.Partial) ;
              string strCommand = Encoding.UTF8.GetString(bufCmd,0,DESCLEN) ;
              return strCommand = strCommand.TrimEnd(FILLCHAR) ;
         }
         ///<summary>
         /// 读取可变部分的长度
         ///</summary>
         ///<param name="s">要读取可变部分长度的Socket</param>
         ///<returns>读取的可变部分的长度</returns>
         publicstaticint ReadDynamicLenFromSocket( Socket s)
         {                 
              byte [] bufCmd = newbyte[DYNAMICLENGTHLEN] ;
              int iCount = s.Receive(bufCmd,0,DYNAMICLENGTHLEN,SocketFlags.Partial) ;
              string strCommand = Encoding.UTF8.GetString(bufCmd,0,DYNAMICLENGTHLEN) ;
              returnint.Parse(strCommand.TrimEnd(FILLCHAR)) ;
         }
         ///<summary>
         /// 读取文本形式的可变信息
         ///</summary>
         ///<param name="s">要读取可变信息的Socket</param>
         ///<returns>读取的可变信息</returns>
         publicstaticstring ReadDynamicTextFromSocket( Socket s)
         {            
              int iLen = ReadDynamicLenFromSocket(s) ;

               byte [] buf = newbyte[iLen] ;
              string strInfo = "" ;

               int iReceiveded = 0 ;
              int iReceiveing = 0 ;
              while(iReceiveded<iLen)
              {
                   if (iReceiveded + DEALLEN <= iLen)
                        iReceiveing = DEALLEN ;
                   else
                        iReceiveing = iLen - iReceiveded ;                   
                   s.Receive(buf,iReceiveded,iReceiveing,SocketFlags.None) ;    
                   CommunClass.WriteTextToSocket(s,"OK") ;
                   iReceiveded+= iReceiveing ;
              }

               strInfo = Encoding.UTF8.GetString(buf,0,iLen) ;

                            return strInfo ;
         }
         ///<summary>
         /// 读取文件形式的可变信息
         ///</summary>
         ///<param name="s">要读取可变信息的Socket</param>
         ///<param name="strFile">读出后的文件保存位置</param>
         ///<returns>是否读取成功</returns>
         publicstaticbool ReadDynamicFileFromSocket( Socket s,string strFile)
         {            
              int iLen = ReadDynamicLenFromSocket(s) ;
              byte [] buf = newbyte[iLen] ;
              FileStream fs = new FileStream(strFile,FileMode.Create,FileAccess.Write) ;

                            try
              {
                   int iReceiveded = 0 ;
                   int iReceiveing = 0 ;
                   while(iReceiveded<iLen)
                   {
                       if (iReceiveded + DEALLEN <= iLen)
                            iReceiveing = DEALLEN ;
                       else
                            iReceiveing = iLen - iReceiveded ;                   
                        s.Receive(buf,iReceiveded,iReceiveing,SocketFlags.None) ;    
                        CommunClass.WriteTextToSocket(s,"OK") ;
                        iReceiveded+= iReceiveing ;
                   }
                   fs.Write(buf,0,iLen) ;
                   returntrue ;
              }
              catch(Exception err)
              {
                   MessageBox.Show("接收文件失败"+err.Message) ;
                   returnfalse ;
              }
              finally
              {
                   fs.Close() ;
              }             
         }
     }//end class
}//end namespace
面介绍了通讯的基类，下面就是使用那个类进行发送和接收的部分：

二、发送部分：
发送咱们使用了多线程，可以同时进行多个任务，比如发送文件、发送文本等，互不影响：
发送文本方法：
private void StartSendText(string strHost,int iPort,string strInfo)
       {
           SendText stText = new SendText(strHost,iPort,strInfo,new CommunClass.OnSend(OnSendDrawProgress)) ;
           StartThread(new ThreadStart(stText.Send)) ;
       }
下面是他调用用到的一些方法：
开始一个线程
private void StartThread(ThreadStart target)
       {
           Thread doStep = new Thread(target) ;          
           doStep.IsBackground = true ;
           doStep.Start() ;
       }
 发送一部分（本文设置的是1024字节）成功后的回调方法
        public void OnSendDrawProgress(int iTotal,int iSending)
       {  
           if (iTotal != pbMain.Maximum)
               pbMain.Maximum = iTotal ;
                pbMain.Value = iSending ;
       }
因为使用的是线程，所以发送文本使用的是一个发送文本类的方法，该类如下：
public class SendText
     {
          private string Host ;
          private int Port ;
          private string Info ;
          private CommunClass.OnSend onsend ;
         public SendText(string strHost,int iPort,string strInfo,
              CommunClass.OnSend onSend)
         {
              Host = strHost ;
              Port = iPort ;
              Info = strInfo ;
              onsend = onSend ;
         }
         public void Send()
         {
              Socket s = null ;
              try
              {
                   s = CommunClass.ConnectToServer(Host,Port) ;

                    CommunClass.WriteCommandToSocket(s,"SENDTEXT") ;
                   CommunClass.WriteCommandDescToSocket(s,"") ;                  
                   CommunClass.WriteDynamicTextToSocket(s,Info,onsend) ;
              }
              catch (Exception e)
              {
                   MessageBox.Show(e.Message) ;
              }
              finally
              {
                   if (s != null)
                        s.Close() ;
              }
         }

      }//end class

      这样就可以使用一个线程发送文本了。
发送文件的方法也类似：
private void StartSendFile(string strHost,int iPort,string strFile)
       {
           SendFile sfFile = new SendFile(strHost,iPort,strFile,this.pbMain) ;
           pbMain.Value = 0 ;
           StartThread(new ThreadStart(sfFile.Send)) ;       
       }
发送文件的类：
public class SendFile
     {
          private string Host ;
          private int Port ;
          private string FileToSend ;
          private ProgressBar pbar;

          public SendFile(string strHost,int iPort,string strFile,ProgressBar pbMain)
         {
              Host = strHost ;
              Port = iPort ;
              FileToSend = strFile ;
              pbar = pbMain ;
         }
         public void Send()
         {
              Socket s = null ;
              try
              {                  
                   s = CommunClass.ConnectToServer(Host,Port) ;

                    CommunClass.WriteCommandToSocket(s,"SENDFILE") ;
                   CommunClass.WriteCommandDescToSocket(s,"") ;

                                      CommunClass.WriteFileToSocket(s,FileToSend,new CommunClass.OnSend(OnSendDrawProgress)) ;
              }
              catch (Exception e)
              {
                   MessageBox.Show(e.Message) ;
              }
              finally
              {
                   if (s != null)
                        s.Close() ;
              }
         }

                   public void OnSendDrawProgress(int iTotal,int iSending)
         {   
              if (iTotal != pbar.Maximum)
                   pbar.Maximum = iTotal ;

                          pbar.Value = iSending ;
         }        

          }//end class
当然，你发送一个命令让服务器端启动一个程序（靠，这不成木马了吗？）也可以：
俺这里只给出一部分代码，其余的您自己可以发挥以下：
public class ExeCuteFile
     {
          private string Host ;
          private int Port ;
          private string FileName ;
          private string cmdParam ;

                  public ExeCuteFile(string strHost,int iPort,string strFileName,string strCmdParam)
         {
              Host = strHost ;
              Port = iPort ;
              FileName = strFileName ;
              cmdParam = strCmdParam ;
         }

                  public void Send()
         {
                   Socket s = null ;
              try
              {
                   s = CommunClass.ConnectToServer(Host,Port) ;

                    CommunClass.WriteCommandToSocket(s,"EXECUTEFILE") ;
                   CommunClass.WriteCommandDescToSocket(s,FileName) ;
                   CommunClass.WriteDynamicTextToSocket(s,"",null) ;
                   MessageBox.Show(CommunClass.ReadDynamicTextFromSocket(s)) ;
              }
              catch (Exception e)
              {
                   MessageBox.Show(e.Message) ;
              }
              finally
              {
                   if (s != null)
                        s.Close() ;
              }

          }
     }
三、下面是服务器端接受信息的代码：
创建监听：
///<summary>
         /// 再给定的主机和端口上创建监听程序
         ///</summary>
         ///<param name="strAddress"></param>
         ///<param name="iPort"></param>
          private void BuildingServer(string strAddress,int iPort)
         {
              IPAddress ipAddress = Dns.Resolve(strAddress).AddressList[0];

                            try
              {
                   listener = new TcpListener(ipAddress, iPort);   
              }
              catch ( Exception e)
              {
                   AddInfo(e.Message) ;
              }
         }

开始监听：
///<summary>
         /// 开始监听
         ///</summary>
          private void StartListen()
         {
              bool done = false;       

               listener.Start();
              while (!done)
              {
                   Socket s = listener.AcceptSocket() ;
                   if(s != null)
                   {
                        DealWithSocket dws = new DealWithSocket(s,this.tbLog) ;
                        StartThread(new ThreadStart(dws.DealWith)) ;
     &, nbsp;             }
              }        
         }

 private void StartThread(ThreadStart target)
         {
              Thread doStep = new Thread(target) ;
              doStep.IsBackground = true ;
              doStep.Start() ;
         }
开始监听后，对于每一个监听到的客户端的连接都用一个单独的线程来处理,处理通过类DealWithSocket来完成,下面是类代码:
public class DealWithSocket
     {
          private Socket s = null ;
          private TextBox tbLog = null ;
         public DealWithSocket(Socket newSocket,TextBox tbInfo)
         {
              s = newSocket ;
              tbLog = tbInfo ;
         }

          public void DealWith()
         {
              string strCmd = CommunClass.ReadCommandFromSocket(s) ;
              string strDesc = CommunClass.ReadCommandDescFromSocket(s) ;
              AddInfo(strCmd) ;
              switch(strCmd)
              {
                   case "SENDFILE" :
                        CommunClass.ReadDynamicFileFromSocket(s,"e:\\rrr.txt") ;                       
                       break ;
                   case "EXECUTEFILE" :
                       string strParam = CommunClass.ReadDynamicTextFromSocket(s) ;
                       string strResult = ExeCuteFile(strDesc,strParam) ;
                        CommunClass.WriteDynamicTextToSocket(s,strResult,null) ;
                       break ;
                   default:              
                       string strDetail = CommunClass.ReadDynamicTextFromSocket(s) ;
                        AddInfo(strDetail) ;
                       break ;
              }
              try
              {
                   s.Close() ;
              }
              catch (Exception e)
              {
                   AddInfo(e.Message) ;
              }
         }
          private void AddInfo(string strInfo)
         {
              string Info = DateTime.Now.ToLongTimeString() + " "+ strInfo +"\r\n" ;
              tbLog.Text += Info ;
              tbLog.Refresh() ;
         }
          private string ExeCuteFile(string strFileName,string strCmdParam)
         {
              System.Diagnostics.Process proc = new System.Diagnostics.Process() ;
              proc.StartInfo.FileName = strFileName ;
              proc.StartInfo.Arguments = strCmdParam ;
              try
              {
                   proc.Start() ;
                   return "OK" ;
              }
              catch(Exception err)
              {
                   return err.Message ;
              }
         }
     }//end class