在 Windows 服务中使用的最佳计时器

我需要创建一些 Windows 服务，它将每 N 时间段执行一次。
问题是：
我应该使用哪个计时器控件：System.Timers.Timer or System.Threading.Timer一？它对某事有影响吗？

我问这个问题是因为我听到了很多不正确工作的证据System.Timers.Timer在Windows服务中。
谢谢。

Both System.Timers.Timer http://msdn.microsoft.com/en-us/library/system.timers.timer.aspx and System.Threading.Timer http://msdn.microsoft.com/en-us/library/system.threading.timer.aspx将为服务业工作。

您想要避免的计时器是System.Web.UI.Timer http://msdn.microsoft.com/en-us/library/system.web.ui.timer.aspx and System.Windows.Forms.Timer http://msdn.microsoft.com/en-us/library/system.web.ui.timer.aspx，分别适用于 ASP 应用程序和 WinForms。使用这些将导致服务加载额外的程序集，而该程序集对于您正在构建的应用程序类型来说并不是真正需要的。

Use System.Timers.Timer http://msdn.microsoft.com/en-us/library/system.timers.timer.aspx像下面的示例一样（另外，请确保使用类级别变量来防止垃圾收集，如 Tim Robinson 的回答中所述）：

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);
    }
}

/* This code example produces output similar to the following:

Press the Enter key to exit the program.
The Elapsed event was raised at 5/20/2007 8:42:27 PM
The Elapsed event was raised at 5/20/2007 8:42:29 PM
The Elapsed event was raised at 5/20/2007 8:42:31 PM
...
 */

如果你选择System.Threading.Timer http://msdn.microsoft.com/en-us/library/system.threading.timer.aspx，您可以按如下方式使用：

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。