双方
System.Timers.Timer并
System.Threading.Timer会为服务工作。
您要避免使用的计时器是
System.Web.UI.Timer和
System.Windows.Forms.Timer，分别用于ASP应用程序和WinForms。使用这些组件将使服务加载额外的程序集，而这对于您正在构建的应用程序类型并不是真正需要的。
使用
System.Timers.Timer类似下面的示例（此外，请确保使用类级别的变量来防止垃圾收集，如Tim
Robinson的回答所述）：
using System;using System.Timers;public class Timer1{ private static System.Timers.Timer aTimer; public static void Main() { // Normally, the timer is declared at the class level, // so that it stays in scope as long as it is needed. // If the timer is declared in a long-running method, // KeepAlive must be used to prevent the JIT compiler // from allowing aggressive garbage collection to occur // before the method ends. (See end of method.) //System.Timers.Timer aTimer; // Create a timer with a ten second interval. aTimer = new System.Timers.Timer(10000); // Hook up the Elapsed event for the timer. aTimer.Elapsed += new ElapsedEventHandler(OnTimedEvent); // Set the Interval to 2 seconds (2000 milliseconds). aTimer.Interval = 2000; aTimer.Enabled = true; Console.WriteLine("Press the Enter key to exit the program."); Console.ReadLine(); // If the timer is declared in a long-running method, use // KeepAlive to prevent garbage collection from occurring // before the method ends. //GC.KeepAlive(aTimer); } // Specify what you want to happen when the Elapsed event is // raised. private static void onTimedEvent(object source, ElapsedEventArgs e) { Console.WriteLine("The Elapsed event was raised at {0}", e.SignalTime); }}如果选择
System.Threading.Timer，则可以使用以下方法：
using System;using System.Threading;class TimerExample{ static void Main() { AutoResetEvent autoEvent = new AutoResetEvent(false); StatusChecker statusChecker = new StatusChecker(10); // Create the delegate that invokes methods for the timer. TimerCallback timerDelegate = new TimerCallback(statusChecker.CheckStatus); // Create a timer that signals the delegate to invoke // CheckStatus after one second, and every 1/4 second // thereafter. Console.WriteLine("{0} Creating timer.n", DateTime.Now.ToString("h:mm:ss.fff")); Timer stateTimer = new Timer(timerDelegate, autoEvent, 1000, 250); // When autoEvent signals, change the period to every // 1/2 second. autoEvent.WaitOne(5000, false); stateTimer.Change(0, 500); Console.WriteLine("nChanging period.n"); // When autoEvent signals the second time, dispose of // the timer. autoEvent.WaitOne(5000, false); stateTimer.Dispose(); Console.WriteLine("nDestroying timer."); }}class StatusChecker{ int invokeCount, maxCount; public StatusChecker(int count) { invokeCount = 0; maxCount = count; } // This method is called by the timer delegate. public void CheckStatus(Object stateInfo) { AutoResetEvent autoEvent = (AutoResetEvent)stateInfo; Console.WriteLine("{0} Checking status {1,2}.", DateTime.Now.ToString("h:mm:ss.fff"), (++invokeCount).ToString()); if(invokeCount == maxCount) { // Reset the counter and signal Main. invokeCount = 0; autoEvent.Set(); } }}这两个示例均来自MSDN页面。
