Timer::Interval Property

 

Gets or sets the interval, expressed in milliseconds, at which to raise the Elapsed event.

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

public:
[TimersDescriptionAttribute("TimerInterval")]
[SettingsBindableAttribute(true)]
property double Interval {
	double get();
	void set(double value);
}

Property Value

Type: System::Double

The time, in milliseconds, between Elapsed events. The value must be greater than zero, and less than or equal to Int32::MaxValue. The default is 100 milliseconds.

Exception Condition
ArgumentException

The interval is less than or equal to zero.

-or-

The interval is greater than Int32::MaxValue, and the timer is currently enabled. (If the timer is not currently enabled, no exception is thrown until it becomes enabled.)

You use the Interval property to determine the frequency at which the Elapsed event is fired. Because the Timer class depends on the system clock, it has the same resolution as the system clock. This means that the Elapsed event will fire at an interval defined by the resolution of the system clock if the Interval property is less than the resolution of the system clock. The following example sets the Interval property to 5 milliseconds. When run on a Windows 7 system whose system clock has a resolution of approximately 15 milliseconds, the event fires approximately every 15 milliseconds rather than every 5 milliseconds.

No code example is currently available or this language may not be supported.

You can use the following code to determine the resolution of the system clock on the current system:

No code example is currently available or this language may not be supported.

If your app requires greater resolution than that offered by the Timer class or the system clock, use the high-resolution multimedia timers; see How to: Use the High-Resolution Timer.

If the 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 the Enabled property 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.

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. Enabled is then set to false.

System_CAPS_noteNote

If Enabled and AutoReset are both set to false, and the timer has previously been enabled, setting the Interval property causes the Elapsed event to be raised once, as if the Enabled property had been set to true. To set the interval without raising the event, you can temporarily set the Enabled property to true, set the Interval property to the desired time interval, and then immediately set the Enabled property back to false.

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.

using namespace System;
using namespace System::Timers;

public ref class Example
{
private:
    static System::Timers::Timer^ aTimer;

public:
    static void Demo()
    {
        // Create a timer and set a two second interval.
        aTimer = gcnew System::Timers::Timer();
        aTimer->Interval = 2000;

        // Hook up the Elapsed event for the timer. 
        aTimer->Elapsed += gcnew System::Timers::ElapsedEventHandler(Example::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();
    }

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

int main()
{
    Example::Demo();
}
// The 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
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