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 [to] As 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

1.	Create a multi threaded web browsing application.
2.	Show a Continuous Animation During an Asynchronous Process
3.	Load the Data for a Window Asynchronously After It Has Rendered
4.	Check Whether You Are Running on the UI Thread
5.	Ensure That You Are Running on the UI Thread
6.	A Cancellable ProgressBar While Processing on a Background Thread
7.	Show a Continuous Progress Bar While Processing on a Background Thread
8.	Execute a Method Asynchronously Using the Dispatcher Queue
9.	Thread Sleep in Button Click handler
10.	Execute a Method Asynchronously Using a Background Worker Thread
11.	Track the Progress of a Background Worker Thread
12.	Create a Background Worker Thread in XAML
13.	WPF Threading
14.	BlockThread.xaml
15.	Keep the UI from becoming non-responsive in single threaded application which performs a long operation.

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

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