Wpf Backgroundworker

Window x:Class="WpfApp53.MainWindow"
        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"
        xmlns:local="clr-namespace:WpfApp53"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    Grid>
        Grid.RowDefinitions>
            RowDefinition Height="*"/>
            RowDefinition Height="Auto"/>
            RowDefinition Height="Auto"/>
            RowDefinition Height="Auto"/>
        Grid.RowDefinitions>
        ListBox Grid.Row="0" x:Name="listBox1"/>
        ProgressBar Grid.Row="1" x:Name="progressBar1" Height="20" Margin="5"/>
        StackPanel Grid.Row="2" Orientation="Horizontal" Margin="5">
            TextBlock Text="Status: "/>
            TextBlock x:Name="statusTextBox"/>
        StackPanel>
        Grid Grid.Row="3" Margin="10">
            Grid.ColumnDefinitions>
                ColumnDefinition Width="*"/>
                ColumnDefinition Width="*"/>
            Grid.ColumnDefinitions>
            Button Grid.Column="0" x:Name="startBtn" Content="Start" Click="StartBtn_Click"/>
            Button Grid.Column="1" x:Name="cancelBtn" Content="Cancel" Click="CancelBtn_Click"/>
        Grid>
    Grid>
Window>

 1 using System;
 2 using System.Collections.Generic;
 3 using System.ComponentModel;
 4 using System.Linq;
 5 using System.Text;
 6 using System.Threading;
 7 using System.Threading.Tasks;
 8 using System.Windows;
 9 using System.Windows.Controls;
10 using System.Windows.Data;
11 using System.Windows.Documents;
12 using System.Windows.Input;
13 using System.Windows.Media;
14 using System.Windows.Media.Imaging;
15 using System.Windows.Navigation;
16 using System.Windows.Shapes;
17 
18 namespace WpfApp53
19 {
20     /// 

21     /// Interaction logic for MainWindow.xaml
22     /// 
23     public partial class MainWindow : Window
24     {
25         BackgroundWorker bgWorker;
26         public MainWindow()
27         {
28             InitializeComponent();
29             cancelBtn.IsEnabled = false;
30         }
31 
32         private void StartBtn_Click(object sender, RoutedEventArgs e)
33         {
34             listBox1.Items.Clear();
35             startBtn.IsEnabled = false;
36             cancelBtn.IsEnabled = true;
37             bgWorker = new BackgroundWorker();
38             bgWorker.DoWork += BgWorker_DoWork;
39             bgWorker.ProgressChanged += BgWorker_ProgressChanged;
40             bgWorker.RunWorkerCompleted += BgWorker_RunWorkerCompleted;
41             bgWorker.WorkerReportsProgress = true;
42             bgWorker.WorkerSupportsCancellation = true;
43 
44             int maxItems = 50;
45             progressBar1.Minimum = 1;
46             progressBar1.Maximum = 100;
47 
48             statusTextBox.Text = "Starting...";
49             bgWorker.RunWorkerAsync(maxItems);
50         }
51 
52         private void BgWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
53         {
54              if(e.Cancelled)
55             {
56                 statusTextBox.Text = "Cancelled";
57             }
58             else
59             {
60                 statusTextBox.Text = "Completed";
61             }
62             statusTextBox.IsEnabled = true;
63             cancelBtn.IsEnabled = false;
64         }
65 
66         private void BgWorker_ProgressChanged(object sender, ProgressChangedEventArgs e)
67         {
68             double percent = (e.ProgressPercentage * 100) / 50;
69             progressBar1.Value = Math.Round(percent, 0);
70             listBox1.Items.Add(new ListBoxItem { Content = e.ProgressPercentage + " item added" });
71             statusTextBox.Text = Math.Round(percent, 0) + "% percent completed";
72         }
73 
74         private void BgWorker_DoWork(object sender, DoWorkEventArgs e)
75         {
76             int? maxItems = e.Argument as int?;
77             for(int i=1;i)
78             {
79                 if(bgWorker.CancellationPending)
80                 {
81                     e.Cancel = true;
82                     break;
83                 }
84                 Thread.Sleep(200);
85                 bgWorker.ReportProgress(i);
86             }
87         }
88 
89         private void CancelBtn_Click(object sender, RoutedEventArgs e)
90         {
91             bgWorker.CancelAsync();
92             startBtn.IsEnabled = true;
93         }
94     }
95 }