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Timer.Elapsed Event

Occurs when the interval elapses.

Namespace: System.Timers
Assembly: System (in system.dll)

public event ElapsedEventHandler Elapsed
/** @event */
public void add_Elapsed (ElapsedEventHandler value)

/** @event */
public void remove_Elapsed (ElapsedEventHandler value)

In JScript, you can handle the events defined by a class, but you cannot define your own.
Not applicable.

If Enabled is set to true and AutoReset is set to false, the Timer raises the Elapsed event only once, the first time the interval elapses.

If Interval is set after the Timer has started, the count is reset. For example, if you set the interval to 5 seconds and then set Enabled to true, the count starts at the time Enabled is set. If you reset the interval to 10 seconds when count is 3 seconds, the Elapsed event is raised for the first time 13 seconds after Enabled was set to true.

The Elapsed event is raised on a ThreadPool thread. If the processing of the Elapsed event lasts longer than Interval, the event might be raised again on another ThreadPool thread. Thus, the event handler should be reentrant.

NoteNote:

The event-handling method might run on one thread at the same time that another thread calls the Stop method or sets the Enabled property to false. This might result in the Elapsed event being raised after the timer is stopped. The example code for the Stop method shows one way to avoid this race condition.

In the .NET Framework version 2.0 and earlier, the Timer component catches and suppresses all exceptions thrown by event handlers for the Elapsed event. This behavior is subject to change in future releases of the .NET Framework.

The following code example sets up an event handler for the Timer.Elapsed event, creates a timer, and starts the timer. The event handler displays the SignalTime property each time it is raised.

using System;
using System.Timers;

public class Timer1
{
    public static void Main()
    {
        // Normally, the timer is declared at the class level, so
        // that it doesn't go out of scope when the method ends.
        // In this example, the timer is needed only while Main 
        // is executing. However, KeepAlive must be used at the
        // end of Main, to prevent the JIT compiler from allowing 
        // aggressive garbage collection to occur before Main 
        // ends.
        System.Timers.Timer aTimer = new System.Timers.Timer();

        // 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();

        // Keep the timer alive until the end of Main.
        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("Hello World!");
    }
}
 

Windows 98, Windows Server 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

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