Support the Cancellation of a Background Worker Thread : Thread « Windows Presentation Foundation « VB.Net Tutorial

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VB.Net Tutorial » Windows Presentation Foundation » Thread 
16.115.12.Support the Cancellation of a Background Worker Thread
<Window x:Class="WpfApplication1.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="WPF" Width="230" Height="148" >
    <StackPanel>
        <Button Click="StartStop_Click" Name="btnStartStop" Height="34">Start</Button>
        <TextBlock Name="txtBiggestPrime" Margin="5" />
    </StackPanel>
</Window>
//File:Window.xaml.vb

Imports System
Imports System.ComponentModel
Imports System.Windows


Namespace WpfApplication1
  Public Partial Class Window1
    Inherits Window
    Private worker As New BackgroundWorker()

    Private from As Long = 2
    Private [toAs Long = 2000
    Private biggestPrime As Long

    Public Sub New()
      MyBase.New()
      InitializeComponent()
      worker.WorkerSupportsCancellation = True
      AddHandler worker.DoWork, New DoWorkEventHandler(AddressOf worker_DoWork)
      AddHandler worker.RunWorkerCompleted, New RunWorkerCompletedEventHandler(AddressOf worker_RunWorkerCompleted)
    End Sub
    Private Sub StartStop_Click(sender As Object, e As RoutedEventArgs)
      If Not worker.IsBusy Then
        worker.RunWorkerAsync()
        btnStartStop.Content = "Cancel"
        txtBiggestPrime.Text = String.Empty
      Else
        worker.CancelAsync()
      End If
    End Sub

    Private Sub worker_RunWorkerCompleted(sender As Object, e As RunWorkerCompletedEventArgs)
      If e.Cancelled Then
        MessageBox.Show("Operation was canceled")
      End If

      btnStartStop.Content = "Start"
      txtBiggestPrime.Text = biggestPrime.ToString()
    End Sub

    Private Sub worker_DoWork(sender As Object, e As DoWorkEventArgs)
      For current As Long = from To [to]
        If worker.CancellationPending Then
          e.Cancel = True
          Return
        End If
        biggestPrime = current
      Next
    End Sub
  End Class
End Namespace
WPF Support The Cancellation Of A Background Worker Thread
16.115.Thread
16.115.1.Create a multi threaded web browsing application.Create a multi threaded web browsing application.
16.115.2.Show a Continuous Animation During an Asynchronous ProcessShow a Continuous Animation During an Asynchronous Process
16.115.3.Load the Data for a Window Asynchronously After It Has RenderedLoad the Data for a Window Asynchronously After It Has Rendered
16.115.4.Check Whether You Are Running on the UI ThreadCheck Whether You Are Running on the UI Thread
16.115.5.Ensure That You Are Running on the UI ThreadEnsure That You Are Running on the UI Thread
16.115.6.A Cancellable ProgressBar While Processing on a Background ThreadA Cancellable ProgressBar While Processing on a Background Thread
16.115.7.Show a Continuous Progress Bar While Processing on a Background ThreadShow a Continuous Progress Bar While Processing on a Background Thread
16.115.8.Execute a Method Asynchronously Using the Dispatcher QueueExecute a Method Asynchronously Using the Dispatcher Queue
16.115.9.Thread Sleep in Button Click handlerThread Sleep in Button Click handler
16.115.10.Execute a Method Asynchronously Using a Background Worker ThreadExecute a Method Asynchronously Using a Background Worker Thread
16.115.11.Track the Progress of a Background Worker ThreadTrack the Progress of a Background Worker Thread
16.115.12.Support the Cancellation of a Background Worker ThreadSupport the Cancellation of a Background Worker Thread
16.115.13.Create a Background Worker Thread in XAMLCreate a Background Worker Thread in XAML
16.115.14.WPF ThreadingWPF Threading
16.115.15.BlockThread.xamlBlockThread.xaml
16.115.16.Keep the UI from becoming non-responsive in single threaded application which performs a long operation.Keep the UI from becoming non-responsive in single threaded application which performs a long operation.
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