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Canceling a BackgroundWorker when a user selects the Escape key

<UserControl x:Class='SilverlightApplication3.MainPage'     xmlns='http://schemas.microsoft.com/winfx/2006/xaml/presentation'      xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'     xmlns:d='http://schemas.microsoft.com/expression/blend/2008'      xmlns:mc='http://schemas.openxmlformats.org/markup-compatibility/2006'      mc:Ignorable='d'      d:DesignWidth='640'      d:DesignHeight='480'>     <Grid x:Name="LayoutRoot" Background="White" KeyUp="LayoutRoot_KeyUp">         <ProgressBar x:Name="myProgressBar" Height="30" Width="250" Background="White" BorderBrush="Black" BorderThickness="2">             <ProgressBar.Foreground>                 <LinearGradientBrush EndPoint="0.5,1.35" StartPoint="0.5,-0.3">                     <GradientStop Color="#FF67E206" Offset="0"/>                     <GradientStop Color="#FF209900" Offset="0.418"/>                     <GradientStop Color="#FF67E206" Offset="1"/>                 </LinearGradientBrush>             </ProgressBar.Foreground>         </ProgressBar>     </Grid> </UserControl> //File: Page.cs using System; using System.Collections.Generic; using System.Linq; using System.Net; using System.Windows; using System.Windows.Controls; using System.Windows.Documents; using System.Windows.Input; using System.Windows.Media; using System.Windows.Media.Animation; using System.Windows.Shapes; using System.ComponentModel; using System.Threading; namespace SilverlightApplication3 {     public partial class MainPage : UserControl     {         private BackgroundWorker backgroundWorker = null;         public MainPage()         {             InitializeComponent();             backgroundWorker = new BackgroundWorker();             backgroundWorker.WorkerReportsProgress = true;             backgroundWorker.WorkerSupportsCancellation = true;             backgroundWorker.DoWork += new DoWorkEventHandler(backgroundWorker_DoWork);             backgroundWorker.ProgressChanged += new ProgressChangedEventHandler(backgroundWorker_ProgressChanged);                         backgroundWorker.RunWorkerAsync();                                               }         void backgroundWorker_ProgressChanged(object sender, ProgressChangedEventArgs e)         {               myProgressBar.Value = e.ProgressPercentage;                                      }         void backgroundWorker_DoWork(object sender, DoWorkEventArgs e)         {             for (int i = 1; i <= 100; i++)                                                       {                 if (backgroundWorker.CancellationPending == true)                                          return;                                                                              backgroundWorker.ReportProgress(i);                                                    Thread.Sleep(25);                                                                  }                                                                                }         private void LayoutRoot_KeyUp(object sender, KeyEventArgs e)         {               if ((e.Key == Key.Escape) && (backgroundWorker.IsBusy == true))                          backgroundWorker.CancelAsync();                                                }     } }