Timer Constructor ()

 

Initializes a new instance of the Timer class, and sets all the properties to their initial values.

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

Public Sub New

The following table shows initial property values for an instance of Timer.

Property

Initial value

AutoReset

true

Enabled

false

Interval

100 milliseconds

SynchronizingObject

A null reference (Nothing in Visual Basic).

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 Basic > Windows Desktop > Console Application template. 
' Replace the default code in Module1.vb with this code. Then right click the project in Solution Explorer, 
' select Properties, and set the Startup Object to Timer1. 

' To avoid confusion with other Timer classes, this sample always uses the fully-qualified
' name of System.Timers.Timer.

Imports System

Public Class Module1

    Private Shared aTimer As System.Timers.Timer

    Public Shared Sub 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.        
        'Dim aTimer As System.Timers.Timer 

        ' 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)

        ' Hook up the Elapsed event for the timer.  
        AddHandler aTimer.Elapsed, AddressOf 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) 
    End Sub

    Private Shared Sub OnTimedEvent(source As Object, e As System.Timers.ElapsedEventArgs)
        Console.WriteLine("The Elapsed event was raised at {0}", e.SignalTime)
    End Sub
End Class

' 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: