Releases all resources used by the current instance of Timer.
Assembly: mscorlib (in mscorlib.dll)
The following example shows how to free the resources held by a Timer.
The example displays its output in a TextBlock on the UI thread. To access the TextBlock from the callback thread, the example uses the Dispatcher property to obtain a Dispatcher object for the TextBlock, and then uses the Dispatcher.BeginInvoke method to make the cross-thread call.
To run this example, see Building Examples That Use a Demo Method and a TextBlock Control.
Imports System.Threading ' The following Imports are not required for the timer. They merely simplify ' the code. Imports System.Windows.Controls Imports System.Windows.Input ' The Example class holds a reference to the timer, and contains the ' event handler for the MouseLeftButtonUp events that control the demo. ' Public Class Example ' The Shared Demo method sets the starting message and creates an ' instance of Example, which hooks up the handler for the MouseLeftButtonUp ' event. Public Shared Sub Demo(ByVal outputBlock As TextBlock) outputBlock.Text &= "Click to create the timer." & vbLf Dim dummy As New Example(outputBlock) End Sub ' Instance data for the demo. Private phase As Integer = 0 Private t As Timer Public Sub New(ByVal outputBlock As TextBlock) ' Hook up the mouse event when a new Example object is created. Note ' that this keeps garbage collection from reclaiming the Example ' object. AddHandler outputBlock.MouseLeftButtonUp, AddressOf Me.MouseUp End Sub Private Sub MouseUp(ByVal sender As Object, ByVal e As MouseButtonEventArgs) Dim outputBlock As TextBlock = CType(sender, TextBlock) If phase = 0 Then ' On the first click, create the timer. outputBlock.Text &= vbLf & "Creating the timer at " & _ DateTime.Now.ToString("h:mm:ss.fff") & _ ", to start in 1 second with a half-second interval." & vbLf & _ "Click to change the interval from 1/2 second to 1 second." & vbLf & vbLf ' Create a timer that invokes the callback method after one second ' (1000 milliseconds) and every 1/2 second thereafter. The TextBlock ' that is used for output is passed as the state object. Visual Basic ' infers the delegate type, as if you had typed the following: ' New TimerCallback(AddressOf MyTimerCallback) ' t = New Timer(AddressOf MyTimerCallback, outputBlock, 1000, 500) ElseIf phase = 1 Then ' On the next click, change the timer interval to every second. outputBlock.Text &= vbLf & "Changing the interval to one second." & vbLf & _ "Click to destroy the timer." & vbLf & vbLf t.Change(0, 1000) Else ' On the last click, destroy the timer and shut down the demo. outputBlock.Text &= vbLf & "Destroying the timer." & vbLf & _ "Refresh the page to run the demo again." RemoveHandler outputBlock.MouseLeftButtonUp, AddressOf Me.MouseUp t.Dispose() End If phase += 1 End Sub ' The shared callback method is invoked on a ThreadPool thread by the Timer. ' The state object is passed to the callback method on each invocation. In this ' example, the state object is the TextBlock that displays output. In order to ' update the TextBlock object, which is on the UI thread, you must make the ' cross-thread call by using the Dispatcher object that is associated with the ' TextBlock. Private Shared Sub MyTimerCallback(ByVal state As Object) Dim outputBlock As TextBlock = CType(state, TextBlock) Dim msg As String = DateTime.Now.ToString("h:mm:ss.fff") & _ " MyTimerCallback was called." & vbLf outputBlock.Dispatcher.BeginInvoke(displayHelper, outputBlock, msg) End Sub ' The DisplayOutput helper method and its delegate, displayHelper, are used by ' the BeginInvoke method of the Dispatcher object. Private Shared displayHelper _ As New Action(Of TextBlock, String)(AddressOf DisplayOutput) Private Shared Sub DisplayOutput(ByVal tb As TextBlock, ByVal msg As String) tb.Text &= msg End Sub End Class ' This example produces output similar to the following: ' 'Click to create the timer. ' 'Creating the timer at 3:17:36.980, to start in 1 second with a half-second interval. 'Click to change the interval from 1/2 second to 1 second. ' '3:17:38.072 MyTimerCallback was called. '3:17:38.586 MyTimerCallback was called. '3:17:39.101 MyTimerCallback was called. '3:17:39.580 MyTimerCallback was called. ' 'Changing the interval to one second. 'Click to destroy the timer. ' '3:17:39.656 MyTimerCallback was called. '3:17:40.689 MyTimerCallback was called. ' 'Destroying the timer. 'Refresh the page to run the demo again.
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.