Any suggestions? Export (0) Print
Expand All

ElapsedEventArgs.SignalTime Property

 

Gets the date/time when the Timer.Elapsed event was raised.

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

public DateTime SignalTime { get; }

Property Value

Type: System.DateTime

The time the Elapsed event was raised.

The Timer.Elapsed event is raised on a ThreadPool thread, so the event-handling method might run on one thread at the same time that a call to the Timer.Stop method runs on another thread. This might result in the Elapsed event being raised after the Stop method is called. This race condition cannot be prevented simply by comparing the SignalTime property with the time when the Stop method is called, because the event-handling method might already be executing when the Stop method is called, or might begin executing between the moment when the Stop method is called and the moment when the stop time is saved. If it is critical to prevent the thread that calls the Stop method from proceeding while the event-handling method is still executing, use a more robust synchronization mechanism such as the Monitor class or the CompareExchange method. Code that uses the CompareExchange method can be found in the example for the Timer.Stop method.

The following example instantiates a Timer object that fires its Timer.Elapsed event every two seconds (2000 milliseconds), sets up an event handler for the event, and starts the timer. The event handler displays the value of the ElapsedEventArgs.SignalTime property each time it is raised.

// Use this code inside a project created with the Visual C# > Windows Desktop > Console Application template. 
// Replace the code in Program.cs with this code. 

using System;

// To avoid confusion with other Timer classes, this sample always uses the fully-qualified
// name of System.Timers.Timer instead of a using statement for System.Timers.

public class Example
{
    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.
        // You can experiment with this by commenting out the class-level declaration and uncommenting 
        // the declaration below; then uncomment the GC.KeepAlive(aTimer) at the end of the method.        
        //System.Timers.Timer aTimer;

        // Create a timer and set a two second interval.
        aTimer = new System.Timers.Timer();
        aTimer.Interval = 2000;

        // Alternate method: create a Timer with an interval argument to the constructor.
        //aTimer = new System.Timers.Timer(2000);

        // Create a timer with a two second interval.
        aTimer = new System.Timers.Timer(2000);

        // Hook up the Elapsed event for the timer. 
        aTimer.Elapsed += OnTimedEvent;

        // Have the timer fire repeated events (true is the default)
        aTimer.AutoReset = true;

        // Start the timer
        aTimer.Enabled = true;

        Console.WriteLine("Press the Enter key to exit the program at any time... ");
        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) 
    }

    private static void OnTimedEvent(Object source, System.Timers.ElapsedEventArgs e)
    {
        Console.WriteLine("The Elapsed event was raised at {0}", e.SignalTime);
    }
}

// This example displays output like the following: 
//       Press the Enter key to exit the program at any time... 
//       The Elapsed event was raised at 5/20/2015 8:48:58 PM 
//       The Elapsed event was raised at 5/20/2015 8:49:00 PM 
//       The Elapsed event was raised at 5/20/2015 8:49:02 PM 
//       The Elapsed event was raised at 5/20/2015 8:49:04 PM 
//       The Elapsed event was raised at 5/20/2015 8:49:06 PM 

.NET Framework
Available since 1.1
Return to top
Show:
© 2016 Microsoft