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Timer.Interval Property

Gets or sets the interval at which to raise the Elapsed event.

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

member Interval : float with get, set

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.


The interval is less than or equal to zero.


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.)

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.


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 AutoReset property to true.

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

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

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.