c# TCP Socket通讯基础

在做网络通讯方面的程序时，必不可少的是Socket通讯。

那么我们需要有一套既定的，简易的通讯流程。

如下：

<pre name="code" class="csharp">public class PublicSocket
    {
        public const string DOWNLOAD_STATUS_WAIT = "1";
        public const string DOWNLOAD_STATUS_PAUSE = "2";
        public const string DOWNLOAD_STATUS_DOWNLOADING = "3";
        public const string DOWNLOAD_STATUS_DOWNLOADED = "4";
        public const string DOWNLOAD_STATUS_ERROR = "5";

        //private XmlHelper xmlhelper = new XmlHelper();
        private TcpClient tcpMethod = new TcpClient();
        public static string LoginUserName = "";
        public static Socket HeadClient = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
        private static string iAddress = "192.168.1.1";
        private static int iPort = 7888;
        private static IPEndPoint endpoint = new IPEndPoint(IPAddress.Parse(iAddress), iPort);

        public const int LOGIN_NAMEERROR = 100000;
        public const int LOGIN_CODEERROR = 100001;
        public const int LOGIN_ERROR = 100002;
        public const int LOGIN_OK = 100003;

        public static bool AllowUpdate = true;

        public static void SocketConnect()
        {
            try
            {
                if (!HeadClient.Connected)
                {
                    HeadClient.Connect(endpoint);
                }
            }
            catch (Exception ex)
            { }
        }

        public static void SocketClose()
        {
            if (HeadClient.Connected)
            {
                HeadClient.Close();
            }
        }
public static void ThreadGetSingleDownloadedFile(object data)   //object参数可以实现界面传入数据进行使用
        {
            string retMD5 = string.Empty;
            try
            {
                HanleListItemClass formInter = data as HanleListItemClass;

                XmlDocument aa = XmlHelper.BuildXmlDoc("CMD", "1", "1",
                 new List<HollXmlNode> { new HollXmlNode("ID","2",null),
                                        new HollXmlNode("STATE","127",null) });
                //主要为了构建XML文件进行Socket的send操作
                //构造后如下  <?xml version='1.0' encoding='utf-8'?><CMD code='1'  index='1'>
                //                 <ID>2</ID>
                 //                <STATE>127</STATE></CMD>

                byte[] sendaskbyte = Encoding.UTF8.GetBytes(aa.InnerXml.ToString());
                int sendcount = 0;

                try
                {
                    sendcount = HeadClient.Send(sendaskbyte, sendaskbyte.Length, 0);
                }
                catch (Exception ex)
                {
                    // return LOGIN_ERROR;
                }

                if (sendcount == 0)
                {
                    //return LOGIN_ERROR;
                }

                int ret = SingleDownloadedFileWaitBack(formInter);

            }
            catch
            {
                //return LOGIN_ERROR;
            }
        }

        public static int SingleDownloadedFileWaitBack(HanleListItemClass tItemclass)
        {
            byte[] RetData = new byte[36 * 1024];
            Array.Clear(RetData, 0, RetData.Length);
            int datalen = 0;

            try
            {
                datalen = HeadClient.Receive(RetData);

                if (datalen == 0)
                {
                    return -1;
                }

                //接收到服务器返回的信息
                string tcpdatastring = Encoding.UTF8.GetString(RetData).Replace("\0", " "); ;

                //此处可以根据自己需求处理返回的信息 http://www.cnblogs.com/sosoft/

                return 0;

            }
            catch (Exception ex)
            {
                return 0;
            }
        }
    }

然后再界面调用的时候，我们只需要在事件中这么使用即可

 private void button1_Click(object sender, EventArgs e)   

    {  PublicSocket.SocketConnect();   

            ThreadPool.QueueUserWorkItem(new WaitCallback(SocketMethod.ThreadGetTotalState), this);     

  } 

同时也把构建XML的类分享出来，使得编码更加简便

 public class XmlHelper
     {
         private static string xmlinit = "<?xml version='1.0' encoding='utf-8'?><{0} code='{1}'  index='{2}'></{0}>";

         public static XmlDocument BuildXmlDoc(string xmltype, string code, string index, List<HollXmlNode> xmlnodes)
         {
             XmlDocument root = new XmlDocument();
             root.LoadXml(string.Format(xmlinit, xmltype, code, index));

             if (xmlnodes != null)
             {
                 for (int i = 0; i < xmlnodes.Count; i++)
                 {
                     XmlElement parentNode = root.CreateElement(xmlnodes[i].NodeName);

                     XmlText descText = root.CreateTextNode(xmlnodes[i].NodeValue);
                     parentNode.AppendChild(descText);

                     if (xmlnodes[i].NodeAtt != null)
                     {
                         if (xmlnodes[i].NodeAtt.Count > 0)
                         {
                             for (int j = 0; j < xmlnodes[i].NodeAtt.Count; j++)
                             {
                                 parentNode.SetAttribute(xmlnodes[i].NodeAtt[j].AttName, xmlnodes[i].NodeAtt[j].AttValue);
                             }
                         }
                     }

                     root.LastChild.AppendChild(parentNode);
                 }
             }

             return root;
         }

     }

 public class HollXmlNode
     {
         private string _nodename;
         private string _nodevalue;
         private List<HollXmlAttribute> _nodeatt;

         public HollXmlNode(string tnodename, string tnodevalue, List<HollXmlAttribute> tnodeatt)
         {
             _nodename = tnodename;
             _nodevalue = tnodevalue;
             _nodeatt = tnodeatt;
         }

         public string NodeName
         {
             get { return _nodename; }
             set { _nodename = value; }
         }

         public string NodeValue
         {
             get { return _nodevalue; }
             set { _nodevalue = value; }
         }

         public List<HollXmlAttribute> NodeAtt
         {
             get { return _nodeatt; }
             set { _nodeatt = value; }
         }
     }

     public class HollXmlAttribute
     {
         private string _attname;
         private string _attvalue;

         public HollXmlAttribute(string tname, string tvalue)
         {
             _attname = tname;
             _attvalue = tvalue;
         }

         public string AttName
         {
             get { return _attname; }
             set { _attname = value; }
         }

         public string AttValue
         {
             get { return _attvalue; }
             set { _attvalue = value; }
         }
     }