实现多个机器间心跳信息的同步访问处理,适用于主从计算环境下的信息传递处理.

				using System;
				using System.Drawing;
				using System.Collections;
				using System.ComponentModel;
				using System.Windows.Forms;
				using System.Data;
				using System.Net;
				using System.Net.Sockets;
				using System.Text;
				
				namespace HeartbeatServer
				{
					/// 
					/// The ServerForm contains the Functions for receiving and observing
					/// the Heartbeat via UDP local.
					/// 
					public class ServerForm : System.Windows.Forms.Form
					{
						private System.ComponentModel.Container components = null;
				
						private System.Windows.Forms.Label lblError;
				
						private DateTime lastUpdate;
						private Socket udpServerSocket;
						private EndPoint ep = new IPEndPoint(IPAddress.Any, 10000);
						private System.Timers.Timer checkTimer = new System.Timers.Timer();
						private byte[] buffer = new byte[1024];
				
						/// 
						/// Constructor. Initializes the Form, the Socket and the Timer
						/// 
						public ServerForm()
						{
							InitializeComponent();
				
							udpServerSocket = new Socket(AddressFamily.InterNetwork,
								SocketType.Dgram, ProtocolType.Udp);
							udpServerSocket.Bind(ep);
							udpServerSocket.BeginReceiveFrom(buffer, 0, 1024, SocketFlags.None, ref ep, new AsyncCallback(ReceiveData), udpServerSocket);
						
							checkTimer.Interval = 1000;
							checkTimer.AutoReset = true;
							checkTimer.Elapsed += new System.Timers.ElapsedEventHandler(checkTimer_Elapsed);
							checkTimer.Start();
						}
				
						/// 
						/// Dispose used Ressources.
						/// 
						protected override void Dispose( bool disposing )
						{
							if( disposing )
							{
								if (components != null) 
								{
									components.Dispose();
								}
							}
							base.Dispose( disposing );
						}
				
						#region Vom Windows Form-Designer generierter Code
						/// 
						/// Erforderliche Methode f黵 die Designerunterst黷zung. 
						/// Der Inhalt der Methode darf nicht mit dem Code-Editor ge鋘dert werden.
						/// 
						private void InitializeComponent()
						{
							System.Resources.ResourceManager resources = new System.Resources.ResourceManager(typeof(ServerForm));
							this.lblError = new System.Windows.Forms.Label();
							this.SuspendLayout();
							// 
							// lblError
							// 
							this.lblError.Location = new System.Drawing.Point(8, 24);
							this.lblError.Name = "lblError";
							this.lblError.Size = new System.Drawing.Size(280, 16);
							this.lblError.TabIndex = 0;
							// 
							// ServerForm
							// 
							this.AutoScaleBaseSize = new System.Drawing.Size(6, 15);
							this.ClientSize = new System.Drawing.Size(292, 48);
							this.Controls.Add(this.lblError);
							this.Icon = ((System.Drawing.Icon)(resources.GetObject("$this.Icon")));
							this.Name = "ServerForm";
							this.Text = "ServerForm";
							this.ResumeLayout(false);
				
						}
						#endregion
				
						/// 
						/// Main function of this Application. Creates the Form.
						/// 
						[STAThread]
						static void Main() 
						{
							Application.Run(new ServerForm());
						}
				
						/// 
						/// Callback function for the BeginReceiveFrom Function.
						/// Receives the data from the buffer, sets the lastUpdate Variable
						/// and starts a new BeginReceiveFrom.
						/// 
						/// The result of the asynchronous operation.
						void ReceiveData(IAsyncResult iar)
						{
							// Create temporary remote end Point
							IPEndPoint sender = new IPEndPoint(IPAddress.Any, 0);
							EndPoint tempRemoteEP = (EndPoint)sender;
				
							// Get the Socket
							Socket remote = (Socket)iar.AsyncState;
				
							// Call EndReceiveFrom to get the received Data
							int recv = remote.EndReceiveFrom(iar, ref tempRemoteEP);
				
							// Get the Data from the buffer to a string
							string stringData = Encoding.ASCII.GetString(buffer,0,recv);
							Console.WriteLine(stringData);
							
							// update Timestamp
							lastUpdate = DateTime.Now.ToUniversalTime();
				
							// Restart receiving
							if(!this.IsDisposed)
							{
								udpServerSocket.BeginReceiveFrom(buffer, 0, 1024, SocketFlags.None, ref ep, new AsyncCallback(ReceiveData), udpServerSocket);
							}
						}
				
						/// 
						/// Timer event handler. Checks if the last Heartbeat was more than 3 seconds
						/// ago and sets the lable to the Alarm message.
						/// 
						/// Sender of the Event; not used.
						/// Parameter for the Event; not used.
						private void checkTimer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
						{
							// Calculate the Timespan since the Last Update from the Client.
							TimeSpan timeSinceLastHeartbeat = DateTime.Now.ToUniversalTime() - lastUpdate;
				
							// Set Lable Text depending of the Timespan
							if(timeSinceLastHeartbeat > TimeSpan.FromSeconds(3))
							{
								lblError.Text = "No Answer from ClientForm";
								lblError.BackColor = Color.Red;
							}
							else
							{
								lblError.Text = "ClientForm OK";
								lblError.BackColor = Color.Green;
							}
						}
					}
				}