C# BackgroundWorker的使用

<Window x:Class="BackgroundWorkerExam.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="237" Width="229">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition></RowDefinition>
            <RowDefinition></RowDefinition>
            <RowDefinition></RowDefinition>
            <RowDefinition></RowDefinition>
            <RowDefinition></RowDefinition>
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="100"></ColumnDefinition>
            <ColumnDefinition></ColumnDefinition>
        </Grid.ColumnDefinitions>
        <TextBlock Text="X" VerticalAlignment="Center" HorizontalAlignment="Center" Margin="3"></TextBlock>
        <TextBox Margin="3" Grid.Column="1" Name="txtX" VerticalContentAlignment="Center" ></TextBox>
        <TextBlock Text="Y" VerticalAlignment="Center" HorizontalAlignment="Center" Margin="3" Grid.Row="1"></TextBlock>
        <TextBox Margin="3" Grid.Row="1" Grid.Column="1" Name="txtY" VerticalContentAlignment="Center"></TextBox>
        <TextBlock Text="Result" VerticalAlignment="Center" HorizontalAlignment="Center" Margin="3" Grid.Row="2"></TextBlock>
        <TextBox Margin="3" Grid.Row="2" Grid.Column="1" Name="txtResult" VerticalContentAlignment="Center"></TextBox>
        <Button Margin="3" Grid.Row="3" Content="Caculate" Name="btnCaculate" Click="btnCaculate_Click_1"></Button>
        <Button Margin="3" Grid.Row="3" Grid.Column="1" Content="Cancel" Name="btnCancel" Click="btnCancel_Click_1"></Button>
        <ProgressBar Margin="3" Grid.Row="4" Grid.ColumnSpan="2" Name="progBar"></ProgressBar>
    </Grid>

</Window>

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;


namespace BackgroundWorkerExam
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            worker = new BackgroundWorker();
            worker.WorkerSupportsCancellation = true; //支持取消
            worker.WorkerReportsProgress = true;//支持报告进度
            worker.DoWork += worker_DoWork;
            worker.RunWorkerCompleted += worker_RunWorkerCompleted;
            worker.ProgressChanged += worker_ProgressChanged;
        }


        void worker_ProgressChanged(object sender, ProgressChangedEventArgs e)
        {
            this.progBar.Value = e.ProgressPercentage;
        }


        void worker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            if (e.Cancelled) //如果取消了，就不可以访问e.result
            {
                this.txtResult.Text = "Cancelled";
            }
            else
            {
                this.txtResult.Text = e.Result.ToString();
            }
            this.btnCaculate.IsEnabled = true;
            this.btnCancel.IsEnabled = false;
            this.progBar.Value = 100;
        }


        void worker_DoWork(object sender, DoWorkEventArgs e)
        {
            var t = e.Argument as Tuple<int, int>;
            //Thread.Sleep(5000);
            for (int i = 0; i < 10; i++)
            {
                Thread.Sleep(500);
                worker.ReportProgress(i * 10);
                if (worker.CancellationPending)
                {
                    e.Cancel = true;
                    return;
                }
            }
            e.Result = t.Item1 + t.Item2;
        }


        private BackgroundWorker worker;


        private void btnCaculate_Click_1(object sender, RoutedEventArgs e)
        {
            this.btnCaculate.IsEnabled = false;
            this.txtResult.Text = string.Empty;
            this.btnCancel.IsEnabled = true;
            this.progBar.Value = 0;
            worker.RunWorkerAsync(Tuple.Create(int.Parse(txtX.Text), int.Parse(txtY.Text)));
        }


        private void btnCancel_Click_1(object sender, RoutedEventArgs e)
        {
            worker.CancelAsync();
        }
    }
}